Talk:1257 Samalas eruption/Archive 2

Archive 1

Archive 2

Archive 3

Table issue

This table was recently added to the article by Bennylin:

Extended content

Comparison of selected volcanic eruptions Table I. Comparison of selected volcanic eruptions Eruptions Country Location Year Column height (km)  Volcanic Explosivity Index  N. Hemisphere summer anomaly (°C) Fatalities Mount Vesuvius Italy Mediterranean Sea 79 30 5 ? 02001>2,000 Hatepe (Taupo) New Zealand Ring of Fire 126 37 7 ? 00000? Baekdu China / North Korea Ring of Fire 969 36 6–7 ? 00000? 1257 eruption of Mount Samalas Indonesia Ring of Fire 1257 40 7 −2.0 ?? Huaynaputina Peru Ring of Fire 1600 46 6 −0.8 01400≈1,400 Tambora Indonesia / Dutch East-Indies Ring of Fire 1815 43 7 −0.5 71001>71,000 1883 eruption of Krakatoa Indonesia / Dutch East-Indies Ring of Fire 1883 36 6 −0.3 3600036,600 Santa María Guatemala Ring of Fire 1902 34 6 no anomaly 070017,000–13,000 Novarupta USA, Alaska Ring of Fire 1912 32 6 −0.4 000022 Mount St Helens USA, Washington Ring of Fire 1980 19 5 no anomaly 0005757 El Chichón Mexico Ring of Fire 1982 32 4–5 02001>2,000 Nevado del Ruiz Colombia Ring of Fire 1985 27 3 no anomaly 2300023,000 Mount Pinatubo Philippines Ring of Fire 1991 49 6 −0.5 012021,202 Source: Smithsonian Global Volcanism Program for VEI. References

I've been looking at the sources provided - https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/joc.891 and https://web.archive.org/web/20060701152210/http://volcano.si.edu/world/largeeruptions.cfm - and it seems like many of the data in the table are unsupported or omitted. I think that we could make a table on the basis of Oppenheimer 2003, but not one on the basis of the GVP listing as it'd be either cherry-picked or way too long. Or we use a more recent source, such as the "VEI7" source in the article. Opinions? Jo-Jo Eumerus (talk, contributions) 10:56, 2 December 2018 (UTC)

Pre-FAC review

I'll add comments as I go through the article. I'll copyedit as I go; please revert any mistakes.

• Suggest including a timeline chart naming the relevant geological periods.
• The description of the map doesn't match what I see in the map. Suggest making the description "The white area at the north of the island is the Samalas caldera"; there's much less purple inside the white than outside.
• I'm not clear on the difference between Rinjani and Samalas. Google Maps names the main peak Rinjani and doesn't mention Samalas, and the park appears to be "Mount Rinjani National Park". The Samalas caldera is right in the middle of what the map calls Rinjani.

-- More to come, but I really need to understand this point before I can copyedit safely. Mike Christie (talk - contribs - library) 21:25, 30 December 2018 (UTC)

Thanks, in order:

• Sure? This article is mostly about recent (last 2000 years) events.

  Good point; probably not worth it. Mike Christie (talk - contribs - library) 22:19, 30 December 2018 (UTC)

• Well, white is the margin of the caldera and some neighbouring mountains. I wonder if a closer crop would work better as you can actually discern the pink caldera there.
• Ugh. This is something that has been bugging me for a while - in the vast majority of sources that discuss Rinjani, the whole volcano-caldera complex is called "Rinjani", but the sources that discuss this eruption specifically it is subdivided into an easterly "Rinjani" and a westerly "Samalas", the latter of which is not only the site of the caldera and the mega eruption, but also the place of the presently active centre. Because this article is written about the eruption it uses that terminology, also to distinguish between the two volcanic centres. I've written a sentence about them being neighbouring volcanoes, does that work?

@Mike Christie: Jo-Jo Eumerus (talk, contributions) 22:06, 30 December 2018 (UTC)

Do the sources that separate the two make it clearly exactly what is being referred to as "Samalas", and what is being referred to as "Rinjani"? E.g. could the map be marked up to show the difference, if we wanted to? Perhaps the crescent-shaped white ridge to the east is Rinjani in those sources? If we can make it clearer, I think it would be fine to put in a footnote giving essentially the same explanation you just gave me; that would really help the reader. Mike Christie (talk - contribs - library) 22:19, 30 December 2018 (UTC)

Yes, they make it quite clear. I can cook up a cropped image on the fly, but labelling it takes a bit more. Jo-Jo Eumerus (talk, contributions) 22:44, 30 December 2018 (UTC)

@Mike Christie: Got a labelled map here Jo-Jo Eumerus (talk, contributions) 10:40, 31 December 2018 (UTC)

I switched to that and increased the size in order to make the labels readable. I think we could now rewrite the caption; perhaps just "The volcano-caldera complex in the north of Lombok". Mike Christie (talk - contribs - library) 11:27, 31 December 2018 (UTC)

Sure, done. Jo-Jo Eumerus (talk, contributions) 11:54, 31 December 2018 (UTC)

Continuing comments:

• How about adding labels for Lombok, Sumbawa, and Bali to the map? There's just enough of Bali visible for an arrow and a label to be useful. Labelling the Gilli islands would be nice but I think it would look a bit crowded.
• Now we have the labeled map, I think the first sentence of the "General geology" section should clarify that locally the name "Mount Rinjani" is used for the whole complex, but in discussions of the geological history it is divided into Samalas and Rinjani. The lead will have to be tweaked too, for the same reason. (I haven't looked at the lead yet; I will do that last.) You could also take the opportunity to mention the "Rinjani Tua" name, which is a bit out of place in the next paragraph where you have it now.
• this last eruption generated the Rinjani pumice: what does "last" mean here? A date range is given so do you mean that there was an identifiable final eruption in that date range?
• I'd move the explanation of "dense rock equivalent" to a note -- it's helpful but putting the explanation inline breaks up the flow.
• The deposits of the last eruption..., although later research suggests that this eruption may have occurred on Samalas instead. If this is the same last eruption that generated the Rinjani pumice I think we need the caveat earlier -- so the Rinjani pumice could be from Samalas?
• Is the Propok pumice tentatively assigned to Rinjani, or Samalas, or could it be either?
• Later volcanic activity occurred in the Segara Anak caldera, forming the Segara Munac, Rombogan, and Barujari volcanoes: we haven't named the caldera to this point, so how about making the previous sentence "when a large eruption destroyed Samalas volcano and formed the Segara Anak caldera"? Also, it seems odd to talk about Samalas being destroyed when we've identified it on the map. Can we say "largely destroyed" or something like that?
• So Segara Munac, Rombogan, and Barujari are volcanoes within what used to be Samalas? None of these are mentioned before or after so it's not clear where they are.
• Per MOS:CONVERSIONS I don't think you need to supply conversions for the units; this is a scientific article.
• In the eruption section, I think it would be best to start with the statement about how the sequence of events has been constructed, and then mention that it probably began in September. I see that's sourced separately, though, and I would guess that's because it's not derived from the same analysis -- perhaps some ice core data is granular enough to determine when in the year it occurred?
• Pyroclastic flows even crossed the Bali Sea, reaching the Gili Islands to the northwest: a little too dramatically phrased, given that the furthest island is only a mile or two away, and the Bali Sea is many times larger than that.
• Just as an FYI, since I saw you removed the recently-added table as unsupported: it's been added to Mount Tambora, and probably the other articles too -- you may want to remove it from there. And I see Mount Tambora used to be a featured article -- might not be too hard to bring it back up to FA level if you're interested.
• I think I know what "fountain-like" means, but is there a suitable link for it?

Stopping there for now; I should have some more time later today. Mike Christie (talk - contribs - library) 12:30, 31 December 2018 (UTC)

Thanks, in order:

• Uploaded another version with more labels. I am not sure why it isn't appearing here, it does show OK on Commons...

  It shows up for me -- probably a caching issue. Mike Christie (talk - contribs - library) 13:55, 1 January 2019 (UTC)

  Aye, now it also displays for me. Jo-Jo Eumerus (talk, contributions) 15:47, 1 January 2019 (UTC)

• I moved the mention of Rinjani Tua up, but I have a slight problem with the terminology that it isn't actually said anywhere how the distinction came to pass. http://geomagz.geologi.esdm.go.id/rinjani-dari-evolusi-kaldera-hingga-geopark/ has some discussion on why Rinjani Tua is also known as Samalas, but it's in Bahasa Indonesia and I am only this trusting of Google Translate.

  I think that's OK; the page seems unambiguous that Rinjani Tua is another name for Samalas. However, the cross sectional diagram of the caldera and the associated text makes it seem that Samalas/Rinjani Tua is the name used for the original volcano, and Mount Rinjani is the remnant peak that was originally part of the slopes of Samalas. If that's correct, then the introductory statement "Samalas and Mount Rinjani are two adjacent volcanoes" isn't accurate. I haven't looked through the journal papers yet, so I don't know if that's correct, but if it is I think it might be beneficial to reorganize the text to clarify this, giving Samalas and its history first, and then mentioning Mount Rinjani. Something like this: "Samalas was a volcano on Lombok, in Indonesia. It erupted in 1257, leaving a remnant peak, Mount Rinjani... Lombok is one of the Lesser Sunda Islands...". Would that work? Mike Christie (talk - contribs - library) 14:38, 1 January 2019 (UTC)

  Although looking at a later response of yours it appears that Rinjani is thought to have been independently active prior to 1257, so these really are two volcanoes in that case, even though the cross-section doesn't make it seem that way. Is this clear in the sources? Mike Christie (talk - contribs - library) 14:54, 1 January 2019 (UTC)

  Tough question. Volcanoes are somewhat fractal, you can either treat Samalas and Rinjani as the same volcano or as two different ones, similar to how a rock consisting of two connected bits could be called one or two rocks. I believe that saying "two volcanic edifices" would perhaps be clearest but I know that you've opposed "edifice" before. Jo-Jo Eumerus (talk, contributions) 15:47, 1 January 2019 (UTC)

  The more I learn about the subject the more I can see that technical vocabulary is sometimes a good way to solve problems. Could you add an entry to glossary of geology for edifice? I see each of those are linked, but that's not necessary for a glossary, so long as you have a sourced definition. Then you could use "edifice" and link it to the "E" section. Mike Christie (talk - contribs - library) 17:27, 1 January 2019 (UTC)

  Did look for a source, this one has a bunch of technical ones, do you think any of these would work? Jo-Jo Eumerus (talk, contributions) 19:05, 1 January 2019 (UTC)

• "Last" means the last date in the range, i.e the Rinjani Pumice was erupted 2,550 ± 50 BP.

  Then how about "The Rinjani volcano formed from a series of eruptions between 11,940 ± 40 and 2,550 ± 50 BP;[7] the last of these generated..."? Mike Christie (talk - contribs - library) 14:54, 1 January 2019 (UTC)

  That works. Implemented. Jo-Jo Eumerus (talk, contributions) 15:47, 1 January 2019 (UTC)

  Did you mean to leave out "from a series of eruptions"? I think that would make it much clearer. Mike Christie (talk - contribs - library) 17:27, 1 January 2019 (UTC)

  Apparently per the source it has "ages ranging from X to Y", it looks like Vidal 2015 agrees. Jo-Jo Eumerus (talk, contributions) 19:05, 1 January 2019 (UTC)

• Moved dense rock equivalent explanation to a footnote.
• Aye, the source hedges a bit and says that the Rinjani Pumice is more likely to come from Samalas rather than from Rinjani.
• Per page #3 of the souce, the Propok Pumice "A sub-plinian event occurred ... from a lateral vent located on the eastern flanks of Rinjani and produced the Propok Pumice deposit"
• I am guessing here science jargon is the issue - for scientists and the source, a volcano losing most of its volume and leaving a caldera would be called "destruction".

  My concern is the use of the present tense for mentions of Samalas in the text -- if it was destroyed, and the remains are no longer called Samalas, then I would expect it to be referred to only in the past tense. This is connected to my comment about the first sentence of the "General geology" section: are we saying that something still exists that is called Samalas, or is Mount Rinjani part of what is left of Samalas? Mike Christie (talk - contribs - library) 15:10, 1 January 2019 (UTC)

  Ah, tense. I believe that past tense should be used as nowadays the volcano or volcanic complex is known as "Rinjani". Jo-Jo Eumerus (talk, contributions) 15:47, 1 January 2019 (UTC)

• Rewrote the later volcanoes sentence, for some reason the spelling was jinxed.
• The conversion thing is mostly an artifact as it's easier to type the coord template than to type out the units for me but we can replace it.
• Yes, the month time based on the ice core data and has an uncertainty of 2-3 months. I've reordered the sentences, I presume we can still add the uncertainty factor.

  That works. I think you could either add a footnote explaining that the month is based on ice core data, and giving the uncertainty; or (probably better) you could add that information to the "Research history" section. Mike Christie (talk - contribs - library) 15:05, 1 January 2019 (UTC)

  Did that, in text. Jo-Jo Eumerus (talk, contributions) 15:47, 1 January 2019 (UTC)

• Probably could stand a rewrite yes (not sure what to replace it with, though), although if my understanding is correct that pyroclastic flows can cross the sea was quite a major discovery.

  Fair enough, but I knew the Bali Sea was large and didn't get an impression of scale from the way it was written. Labelling the Gili Islands on the map helps. How about "Pyroclastic flows even crossed several miles of the sea to the west, reaching the nearby Gili Islands"? I made it "west" rather than "northwest" because the islands are more or less due west of Samalas, even though they're on the northwestern flank of Lombok. Mike Christie (talk - contribs - library) 15:03, 1 January 2019 (UTC)

  ​ I changed that to Pyroclastic flows crossed 10 kilometres (6.2 mi) of the Bali Sea, reaching the Gili Islands to the northwest of Samalas. Jo-Jo Eumerus (talk, contributions) 15:47, 1 January 2019 (UTC)

  Struck. I made it "west of", per the map. Mike Christie (talk - contribs - library) 17:27, 1 January 2019 (UTC)

• After writing African humid period (something that might interest you, as well) I don't think I'll be doing a mega article for a while. I was thinking of writing a new table based on more recent sources; maybe something for next year.
• I don't think we currently have a suitable link.

@Mike Christie:Jo-Jo Eumerus (talk, contributions) 17:12, 31 December 2018 (UTC)

I've added some replies above. More than one outstanding question is related to the Samalas/Rinjani naming issue, so let's talk about that. You say that they can be viewed as either one or two volcanoes; that makes sense to me, but we need consistent usage in the article.

• Option 1: "Samalas" means the entire volcano prior to 1257, and has no referent after 1257. Rinjani means the remnant volcano after 1257. Pre-1257 activity assigned to what is now Rinjani could be described as activity of Samalas, or of "what is now Rinjani" or some similar phrase.
• Option 2: "Rinjani" refers to the existing mountain, both before and after 1257. Samalas refers to the other parts of the pre-1257 mountain.

Will the sources support either of these usages? I don't want to put in place something that's OR, but the terminology is currently confusing and I think we need to do something. Mike Christie (talk - contribs - library) 17:27, 1 January 2019 (UTC)

​Regarding the name issue:

• Lavigne 2013 uses the second usage and "Rinjani volcanic complex" for Samalas+Rinjani.
• Vidal 2015 uses the second usage and "Samalas-Rinjani caldera" for the caldera. Notably, it claims that Rinjani last erupted 2,550 BP.
• Vidal 2016 only discusses the eruption and otherwise follows Lavigne 2013
• Métrich 2018 uses the second usage.
• Rachmat 2016 is somewhat incoherent, it has an Old Rinjani also called Samalas, Young Rinjani which apparently corresponds to the eastern volcano and unlike Vidal 2015 apparently had a post-caldera eruption - this disagreement should probably be noted -, and Rinjani volcanic complex.
• Mutaqin 2018 has the second usage, but also defines Barujari as a third volcano. (Probably not geologically correct, as Barujari rises in the Samalas caldera)
• Global Volcanism Program uses the term Rinkani for the whole complex but Samalas for the caldera. It has also an uncertain eruption on the main cone and all other eruptions are on Barujari.

So I'd say Option 2 would be the preferred one. Jo-Jo Eumerus (talk, contributions) 19:05, 1 January 2019 (UTC)

OK, great; looks like most of the sources are fairly consistent. I will think about this and may post some suggested revisions in a bit. Mike Christie (talk - contribs - library) 20:00, 1 January 2019 (UTC)

Here's a suggestion for the first body section:

Samalas (also known as Rinjani Tua) was part of what is now the Rinjani volcanic complex, on Lombok, in Indonesia. The remains of Samalas form the Segara Anak caldera, with Mount Rinjani at its eastern edge. Since the destruction of Samalas, two new volcanoes, Rombogan and Barujari, have formed in the caldera. Rinjani has also been volcanically active, forming its own caldera, Segara Munac.

Lombo is one of the Lesser Sunda Islands in the Sunda Arc of Indonesia, a subduction zone where...

What I've tried to do with this is assemble the purely geographic information for the reader before we get into geological context or eruptive history. It might be better to move all the information about the pumices and eruptions to the eruptive history section too, but that's a separate issue. What do you think? Mike Christie (talk - contribs - library) 02:54, 3 January 2019 (UTC)

@Mike Christie:I don't think that Segara Muncar (sp? It seems like every source has a different spelling for Rombogan/Rombongan and Muncar/Munac) is actually a caldera, it's rather a crater. Otherwise it seems good providing that each statement stays attached to its source. I think that pumices and eruptions are already in a history section, aren't they? Jo-Jo Eumerus (talk, contributions) 14:07, 3 January 2019 (UTC)

Done; I don't have access to the sources so please check that the citations are still accurate. There's still some material in that section about eruptive activity; if what I've done so far is OK I'll see if some of that might be moved to the eruption section. Mike Christie (talk - contribs - library) 23:22, 3 January 2019 (UTC)

@Mike Christie:OK, corrected things. I suspect that the FAC page may have questions about the tense, but we can discuss that there. Jo-Jo Eumerus (talk, contributions) 10:42, 4 January 2019 (UTC)

Oops, forgot to fix "caldera" and "Munac"; thanks for catching that. I should have more time over the weekend to continue this. Mike Christie (talk - contribs - library) 12:11, 4 January 2019 (UTC)

Arbitrary break 1

• We have both The Rinjani volcano...the last of these generated the Rinjani pumice, which is unequivocal that the pumice was formed by Rinjani, and later research suggests that this eruption may have occurred on Samalas instead. I think this should be recast so that the reader is not told something that is later qualified. Am I right in thinking that all the eruptions listed in this paragraph prior to 1257 are from Rinjani or Samalas, but can't definitely be pinned down to one or other of the two?

  ​ AFAIK the uncertainty is only about that eruption, there is no discussion in sources about the other dates being contested. Jo-Jo Eumerus (talk, contributions) 13:43, 5 January 2019 (UTC)

  OK. Here's a possible rewrite of part of that paragraph:

  The oldest geological units on Lombok Island are from the Oligocene-Miocene, with old volcanic units cropping out in southern Lombok. Samalas was built up by volcanic activity before 12,000 BP. Rinjani formed between 11,940 ± 40 and 2,550 ± 50 BP, with an eruption between 5,990 ± 50 and 2,550 ± 50 BP forming the Propok Pumice with a dense rock equivalent volume of 0.1 cubic kilometres (0.024 cu mi). The Rinjani pumice, with a volume of 0.3 cubic kilometres (0.072 cu mi) dense rock equivalent, may have been deposited by an eruption from either Rinjani or Samalas; it is dated to 2,550 ± 50 BP, at the end of the time range during which Rinjani formed. The deposits from this eruption reached thicknesses of 6 centimetres (2.4 in) at 28 kilometres (17 mi) distance.

  I tried to make it more strictly chronological, and to address the uncertainty in the origin of the Rinjani Pumice. How does that look? A related point: you capitalize "pumice" in "Propok Pumice" but not in "Rinjani pumice"; shouldn't we be consistent? Mike Christie (talk - contribs - library) 14:26, 5 January 2019 (UTC)

  Yep, "Pumice" should be in uppercase in both instances. The proposed paragraph is fine so as long as source-text integrity is maintained; I just made a minor change to the sourcing. Jo-Jo Eumerus (talk, contributions) 14:43, 5 January 2019 (UTC)

  Done; please check I didn't screw up the sourcing. Mike Christie (talk - contribs - library) 14:59, 5 January 2019 (UTC)

  Remedied a minor issue. Jo-Jo Eumerus (talk, contributions) 15:42, 5 January 2019 (UTC)

• The sentence about September 1257 has "probably", with the uncertainty given at the end; it would be nice to combine the two as they are related. How about something like "The eruption occurred within two or three months of September that year, in light of..." or "The eruption occurred in September (plus or minus two or three months), in light of...". I think I prefer the first formulation but either would be an improvement.

  I implemented the first version, parentheticals are odd. Jo-Jo Eumerus (talk, contributions) 13:43, 5 January 2019 (UTC)

• You say "upwind" without explaining how we know the prevailing wind of the time; I would guess this is because the deposit pattern makes it clear. Is there something citable in one of the sources that would support a clear statement of this in the article?

  Aye, the deposit pattern makes it clear that there were easterly winds but the source does not explicitly say so. Jo-Jo Eumerus (talk, contributions) 13:43, 5 January 2019 (UTC)

• These pyroclastic flows on-land: what's the significance of "on-land"?

  It is difficult to tell the volume of underwater pyroclastic deposits, hence their volume isn't part of the volume given. Jo-Jo Eumerus (talk, contributions) 13:54, 5 January 2019 (UTC)

  OK; I tweaked it a little. Mike Christie (talk - contribs - library) 14:15, 5 January 2019 (UTC)

• The second phreatomagmatic phase has been estimated to have had: suggest cutting "second"; it was the second phase, but this makes it sound as though there were two phreatomagmatic phases.

  Done. Jo-Jo Eumerus (talk, contributions) 13:54, 5 January 2019 (UTC)

• Suggest giving the date of the Minoan eruption as you give dates for the other three.

  That will need some thought, AFAIK the date of the Minoan eruption has been contentious for a long time and reading the sources published in 2018 look like it's still not settled. I'll ask someone. Jo-Jo Eumerus (talk, contributions) 13:54, 5 January 2019 (UTC)

• The paragraph starting "Volcanic rocks ejected..." seems out of place; shouldn't it be further up, with the other paragraphs discussing the eruption fallout? Perhaps move the paragraphs about the volume and explosivity below this and the following ("Pumice falls...") paragraph.

  I'll admit that I am not sure what the ideal sequence would be here; do as you wish. Jo-Jo Eumerus (talk, contributions) 13:54, 5 January 2019 (UTC)

  OK, moved. Mike Christie (talk - contribs - library) 14:15, 5 January 2019 (UTC)

• The various phases of the eruption are also known as P1 (phreatic and first magmatic phase): can we cut "first"?

  Aye, we can. Jo-Jo Eumerus (talk, contributions) 15:42, 5 January 2019 (UTC)

  Done. Mike Christie (talk - contribs - library) 17:35, 6 January 2019 (UTC)

• The P1 and P3 phases of the eruption together lasted between 12 and 15 hours. This seems an odd thing to say, so perhaps I'm misunderstanding something. The phases are consecutive, I assume, so does this mean that the time from the start of P1 to the end of P3 is about 12-15 hours, or that it's X + 12-15, where X is the duration of P2?

  The latter, for proxy data reasons we can only know how long P1+P3 lasted, not how long each lasted or what the duration of P2 might be. Jo-Jo Eumerus (talk, contributions) 15:42, 5 January 2019 (UTC)

  OK, I've tried a clarification. Mike Christie (talk - contribs - library) 17:35, 6 January 2019 (UTC)

• You capitalize "Plinian" in one usage but not another; which is correct? And "ultraplinian" links to "Ultra Plinian", so I wonder about that too.

  I think Plinian should always be uppercase. Jo-Jo Eumerus (talk, contributions) 15:42, 5 January 2019 (UTC)

  Googling and checking ngrams, it appears that "ultraplinian" is never spelt with a capital P unless it's hyphenated, and that lower-case "plinian" is starting to gain currency. I'll leave this to you but I'd suggest being consistent. Mike Christie (talk - contribs - library) 17:35, 6 January 2019 (UTC)

  Standardized to uppercaps. Jo-Jo Eumerus (talk, contributions) 19:22, 6 January 2019 (UTC)

• You have both "This tephra" and "These tephras"; can we make these consistent?

  Went with singular. Jo-Jo Eumerus (talk, contributions) 19:22, 6 January 2019 (UTC)

  Tweaked to avoid repetition. Mike Christie (talk - contribs - library) 00:48, 8 January 2019 (UTC)

• The last paragraph of the "Eruption" section contains some disconnected information. I'd suggest moving most of it to the "Research history section", and move the last sentence up to the end of the first paragraph of the body, since it describes local geography.

  ​ I think that the last sentence should probably be kept somewhere where pyroclastic flows are discussed; the hazard implication is an important point IMO. Jo-Jo Eumerus (talk, contributions) 19:22, 6 January 2019 (UTC)

  OK, but the other sentences should be in the following section, I would think. Mike Christie (talk - contribs - library) 00:48, 8 January 2019 (UTC)

That complete the geology section; I should have more time to look at the next section this evening. Mike Christie (talk - contribs - library) 18:29, 6 January 2019 (UTC)

Incidentally, I am not sure if this is a good edit; the source does not explain why it doesn't give an estimated duration for P2, it just doesn't give one. Jo-Jo Eumerus (talk, contributions) 19:25, 6 January 2019 (UTC)

Agreed; I made an unwarranted assumption. Tweaked -- how does that look? Mike Christie (talk - contribs - library) 00:48, 8 January 2019 (UTC)

Research history

I'm not sure if other readers would agree with me, but I'd like to see more detail, if available, on the research history. This section of the article is a detective story, so let's give the reader the clues.

Some specifics:

• first identified...from medieval records...which mentioned climate phenomena: can we get more details? Both on the sources and the climate phenomena?

  No, that source does not give any more details. Jo-Jo Eumerus (talk, contributions) 07:24, 8 January 2019 (UTC)

  What does it cite for that statement? Mike Christie (talk - contribs - library) 10:10, 8 January 2019 (UTC)

  It does not give its own source, but it appears to refer to Lavigne 2013. Jo-Jo Eumerus (talk, contributions) 16:38, 8 January 2019 (UTC)

• I just spent some time digging through my references on ice cores to find whatever the original paper was that showed the spike in the Crête core, but couldn't find it. It might be Hammer et al (1980) in Nature, "Greenland ice sheet evidence of post-glacial volcanism and its climatic impact", which I don't have. Do the summary sources give the citation for the article in which the spike around 1257 was first reported?

  It's Hammer et al. indeed; put in a request on WP:RX. Jo-Jo Eumerus (talk, contributions) 07:24, 8 January 2019 (UTC)

  Got it, that publication does mention a spike in 1259. It appears to be firsthand information, too. Jo-Jo Eumerus (talk, contributions) 16:38, 8 January 2019 (UTC)

• sulfur deposits in the polar ice caps had already showed that climate disturbances reported in that time were due to a volcanic event: can we put a date to "already"? And any details?

  Also asked at WP:RX. Jo-Jo Eumerus (talk, contributions) 07:24, 8 January 2019 (UTC)

  Apparently it does not give a date, but it refers to crop failures and the London famine described farther down. Jo-Jo Eumerus (talk, contributions) 16:38, 8 January 2019 (UTC)

• You mention "These ice cores", but only Crête has been named to this point.

  Also asked at WP:RX. Jo-Jo Eumerus (talk, contributions) 07:24, 8 January 2019 (UTC)

  The source refers to Lavigne 2013 and does not give any specific ice core, but explicitly says that it was recorded at both poles i.e more than one ice core. Jo-Jo Eumerus (talk, contributions) 16:38, 8 January 2019 (UTC)

• The "later-discovered sulfate spikes" interjection disrupts the flow; I'd move it to a note, or at least get it out of the middle of this paragraph.

  ​ Moved to note. I've been always wondering what volcano may be the source of the 44BC spike, Mount Etna has been proposed in the past but it sounds questionable to me. Jo-Jo Eumerus (talk, contributions) 07:24, 8 January 2019 (UTC)

• Babad Lombok seems worth a red link.

  Added one. Jo-Jo Eumerus (talk, contributions) 07:24, 8 January 2019 (UTC)

• I'm curious about "polar ice caps" which is plural -- the Arctic has multiple small ice caps, plus Greenland, but the sea ice is useless for palaeoclimatology. Is the reference here to Greenland plus the Antarctic? I may be being too picky here since I know a bit more about ice cores than I do about geology.

  Yes, I think that it refers to Greenland. Jo-Jo Eumerus (talk, contributions) 07:24, 8 January 2019 (UTC)

• The first words of the section seem unnecessary -- we know we're talking about a major volcanic event in 1257-1258.

  It is more meant as an introductory sentence. Jo-Jo Eumerus (talk, contributions) 07:24, 8 January 2019 (UTC)

  Understood, but I'm not sure it's needed. This can wait till we're sure there's no more content to add. Mike Christie (talk - contribs - library) 10:10, 8 January 2019 (UTC)

If the sources exist, I'd like to see this section go something like this:

Medieval records from the northern hemisphere, such as X and Y, mention <climate events> in the late 13th century, which had led to speculation about a contemporary volcanic event as early as <date>. Sulfur deposits in polar ice caps had been found in 19xx that were dated to about this time. Further evidence was found in the 198x ice core from Crête, in Greenland; a layor of rhyolitic ash was found, with an associated increase in sulfate concentration.

And so on. Make it absolutely chronological if you can, because that makes it into a story rather than a summary. Mike Christie (talk - contribs - library) 01:34, 8 January 2019 (UTC)

Well, the general problem with writing a research history about this is that the eruption was first known as the "1257-1258 eruption" or "mid-13th century eruption", both of which are extremely difficult to search for. Jo-Jo Eumerus (talk, contributions) 07:24, 8 January 2019 (UTC)

Yes, I can see that. Chasing down the citations from the secondary sources is probably the best way to go, and in any case it might be OR to include something not cited by the secondary sources. I think it's worth a bit more effort to put some flesh on the bones of this section. Mike Christie (talk - contribs - library) 10:10, 8 January 2019 (UTC)

Do you have access to either of these? They show some possibly useful snippets on Google Scholar.

• Burroughs, W. J. "Some observations on the climate in Britain during the 13th and 14th centuries." Weather 36, no. 5 (1981): 140-145.
• Scuderi, Louis A. "Tree-ring evidence for climatically effective volcanic eruptions." Quaternary Research 34, no. 1 (1990): 67-85.

I tried searching for variations on "end of the Medieval Warm Period" but didn't get anything unambiguously useful; that might be a useful search term, though. Mike Christie (talk - contribs - library) 10:20, 8 January 2019 (UTC)

@Mike Christie:Only the second, which has a driveby mention.

Incidentally, since this will probably take a while I was thinking to send Allison Guyot to FAC without pre-FAC review so that it can be reviewed while we are working on Samalas. JoJo Eumerus mobile (talk) 12:04, 8 January 2019 (UTC)

I'll take a look at it this evening or tomorrow morning, if you like. Mike Christie (talk - contribs - library) 12:24, 8 January 2019 (UTC)

Um, "it" is the Samalas or the Allison article? Jo-Jo Eumerus (talk, contributions) 16:21, 8 January 2019 (UTC)

Allison Guyot -- sorry! Mike Christie (talk - contribs - library) 17:13, 8 January 2019 (UTC)

Ah. If you have time, but I don't think that that article needs to wait before FAC so perhaps you can review the nomination when it's live. Jo-Jo Eumerus (talk, contributions) 17:45, 8 January 2019 (UTC)

Sure -- that's better for me as I might be busy for a day or two. I'll watchlist it now. Mike Christie (talk - contribs - library) 18:53, 8 January 2019 (UTC)

Alright, here it is. Did also reply to some other comments here. Jo-Jo Eumerus (talk, contributions) 20:50, 8 January 2019 (UTC)

I see you've already get several comments at the FAC, so I'll hold off there unless it looks like another review is needed. What do you think of my suggestion that more on the details of the research history would be useful? You have Hammer's article in hand; can anything be added from it? Are there citations in there that look like they could be followed up?

The Little Ice Age by Jean M. Grove (accessible on Google Books) appears to have some discussion of the Crête core, and could be useful. I can see a copy for sale on the web and am tempted to buy it though it would take a while to arrive -- it's in New Zealand. If you don't have access to it let me know and I'll buy it. Searching Google Books for "Little ice age samalas" gets several other interestin looking hits. Mike Christie (talk - contribs - library) 02:13, 10 January 2019 (UTC)

Sorry, lately I've got a semi employment with an uncomfortable travel schedule so I haven't been able to do any in-depth source checking due to exhaustion and lack of time.

The problem I see with the Hammer source is that it is just an off mention of narrow tree rings after 1257-1259. Many other sources for "1257 eruption" are similarly laconic. It would be enough to expand and light tree rings in Canada and northwestern Siberia from 1258 and 1259 respectively to and light tree rings in Canada and northwestern Siberia from 1258 and 1259 respectively, an observation also made in California, sure. Do we want to do something like this?

Regarding Grove 2012 (that's the book you mention) based on the snippets I am thinking that it doesn't offer enough new information. There are plenty of sources that discuss Samalas as a possible cause for the Little Ice Age, but what would really help is a review source that discusses the causes of the Little Ice Age overall amd says something like "on balance of probability, the Little Ice Age was caused by orbital forcing/solar minima/a volcanic eruption in 1257 (delete as appropriate) with other factors playing only a minor role". Jo-Jo Eumerus (talk, contributions) 07:38, 10 January 2019 (UTC)

Well, Grove 2012 does appear to be a review source, though I agree if it doesn't survey the possible causes in some detail it's not likely to be of much use. I went ahead and ordered it; I'll let you know if it includes anything useful. I also looked in some of my palaeoclimatology sources to see if there's any mention but couldn't find anything useful. I did see a paper by Bradley cited in Little Ice Age that looked strongly negative on the idea of simultaneous global climate change in the late 13th, so if we add anything else on this I think we should look for scepticism as well.

I'll look at the rest of the article, possibly this evening, and come back to the research history section after that. Mike Christie (talk - contribs - library) 10:16, 10 January 2019 (UTC)

That would be this publication, yes? Jo-Jo Eumerus (talk, contributions) 21:19, 10 January 2019 (UTC)

Sorry, it was this, linked from Medieval Warm Period, not Little Ice Age. Mike Christie (talk - contribs - library) 22:11, 10 January 2019 (UTC)

Ah. That article seem to be mostly criticizing the "Medieval Warm Period" concept, seems like. The point that the Little Ice Age did not start everywhere at the same time is important, though. Note also that I have a question about whether to use the Hammer source; it carries implications for general writing here. Jo-Jo Eumerus (talk, contributions) 07:15, 11 January 2019 (UTC)

Yes, that paper isn't something I think we could cite directly, but it hints that a good survey source might cover a sceptical point of view. I've also ordered a book on the Medieval Warm Period and will see if that has anything when it arrives; I've been acquiring some palaeoclimatology sources so it's something I was considering anyway.

Re Hammer, I don't think it would hurt to mention California, as you suggest above. I was hoping he would do more of a survey of the evidence in a way that would let us give the reader the sequence of evidence, but if it's not there, it's not.

I've started reading the "Social and historical consequences" section and will add notes on that next. I'd only glanced at it before, but now that I look at it I see it might be more of the "story" that I'm hoping for. Mike Christie (talk - contribs - library) 11:51, 11 January 2019 (UTC)

Social and historical consequences

• Western and central Indonesia at the time were dominated by many kingdoms in competition with each other, and they often built temple complexes with inscriptions documenting certain kinds of historical events;[44] however very little direct historical evidence of the consequences of the Samalas eruption exists. Suggest "Western and central Indonesia at the time were divided into kingdoms in competition with each other which often built temple complexes with inscriptions documenting historical events, but little direct historical evidence of the consequences of the Samalas eruption exists".

  Done. Jo-Jo Eumerus (talk, contributions) 16:08, 11 January 2019 (UTC)

• It sounds a bit odd to say there's very little evidence and then immediately describe the Babad Lombok. I can't see the source, but could this be phrased as something like "...with inscriptions documenting historical events. None of these inscriptions record the consequences of the Samalas eruption, but the Babad Lombok, ..."?

  Well, the source says Similarly, very little is known about the devastating effects of the Samalas eruption upon the resident population of Lombok. The Babad Lombok (Wacana, 1979) chronicles the existence of the Pamatan kingdom centered in east Lombok and adjacent to Rinjani.. I think "little" here means "only Babad Lombok" Jo-Jo Eumerus (talk, contributions) 16:08, 11 January 2019 (UTC)

• Similarly the sentence about Pamatan is a bit back-and-forth; it starts by saying it was destroyed, with the reader likely to assume this is because of the volcano, and then it hedges its bets by saying there's no clear evidence. I think this could be reworded to put the uncertainty earlier. I also can't tell if the capital is known to have been destroyed by the volcano, and the cause of the kingdom's destruction is unknown, or if both causes are unknown.

-- Mike Christie (talk - contribs - library) 12:34, 11 January 2019 (UTC)

• ​ After comparing Lavigne 2013 and Alloway 2017 it seems like the problem is that with Pamatan being an undiscovered city/kingdom, the only source about its existence and history and its destruction is this Babad Lombok. So it's probably not so much that that anything is "unknown" as much as that we know only from one source (I note that Alloway 2017 does not raise any question about its reliability). Jo-Jo Eumerus (talk, contributions) 16:08, 11 January 2019 (UTC)

Struck the last two points above after rereading and a slight copyedit. Mike Christie (talk - contribs - library) 15:50, 12 January 2019 (UTC)

• Changes in archeological sites of the Pacific may have been caused by a sea level drop that occurred after 1250, and the 1991 eruption of Pinatubo has been linked to small drops in sea level: Can we draw the connection more explicitly, using the source? What's the mechanism by which an eruption leads to a sea-level drop?

  That source does not bother to detail what sea levels have to do with volcanoes, but from this one and others I know it's a matter of thermal expansion that the ocean undergoes when it absorbs energy - hence why sea levels are rising with global warming - and vice versa when it loses energy, such as after a volcanic winter. Jo-Jo Eumerus (talk, contributions) 20:44, 12 January 2019 (UTC)

  OK -- I think other reviewers are likely to ask about this, but there's nothing wrong as written, so I'm striking this. If there were a section in volcanic winter about this effect we could link to that, but there isn't. Mike Christie (talk - contribs - library) 12:06, 13 January 2019 (UTC)

• The first settlement of New Zealand most likely occurred 1230–1280 AD: See the discussion of wiggle-matching in radiocarbon dating; I checked the source there and Walker (2005) isn't absolutely saying that there's no way humans were there before 1290, but he gives it strong support. How reliable do you think your source, which I see is 2016, is on the dates?

  You know, when I decided to apply that source I was wondering the same thing. According to German Wikipedia de:Atholl John Anderson is a historian who specializes on Pacific prehistory so a good source. It didn't seem to me that he was the authoritative source on the history of New Zealand so I looked for others, and I got the impression that his timeframe is mostly agreed upon. Looking around I see that this source claims that some human disturbance occurred just before the Kaharoa eruption c. 1314 and if we consider that there would be a lag time between the first arrivals and the earliest substantial environmental impacts it might still add up. I did not find a review article on the detailed settlement history. Jo-Jo Eumerus (talk, contributions) 20:44, 12 January 2019 (UTC)

  If there's support for these dates beyond this one author that's good enough. Mike Christie (talk - contribs - library) 12:06, 13 January 2019 (UTC)

• The consequences of the Samalas eruption have been analyzed thanks to contemporary chronicles in Europe, which documented anomalous weather conditions in 1258. Suggest "Contemporary chronicles in Europe mention unusual weather conditions in 1258."

  Done. Jo-Jo Eumerus (talk, contributions) 20:44, 12 January 2019 (UTC)

• The paragraph on Europe makes no comment about how definitely these phenomena are associated with Samalas. Guillet et al. 2017, judging from the abstract, says that the problems are not all directly caused by Samalas, though it exacerbated them. Can we put some of that uncertainty into this paragraph? This applies to the other sources used, such as Stothers, if they convey uncertainty.

  ​Stothers does not really discuss anything like that. Guillet 2017 and also Newhall 2018 do mention the uncertainty, with Newhall referencing Guillet that some famines - the Shôga famine in Japan - began before the Samalas eruption and that England has seen other non-volcanic famines of equal or larger severity. Most other sources which discuss the 1258 England famine take the connection to Samalas for granted, seems like. I'll ask at WP:RX for a copy of the later source [1]. I note that Guillet 2017 is accessible from here. Jo-Jo Eumerus (talk, contributions) 20:44, 12 January 2019 (UTC)

  Got Campbell 2017, apparently it also indicates that the English famine had begun before the Samalas eruption. Jo-Jo Eumerus (talk, contributions) 11:09, 13 January 2019 (UTC)

  For me the issue is this sentence: In Europe, excess rain and cold and high cloudiness damaged crops and caused famines followed by...; it's the first to mention famines, and it seems to unambiguously blame the weather of that year, implying the famine did not start earlier. I think we need to mention no later than this sentence that some sources give an earlier start date for the famine. Mike Christie (talk - contribs - library) 12:09, 13 January 2019 (UTC)

  I did a little change to the Europe sentence. One thing I've noticed is that the sources discussing an earlier start of the famine (such as Guillet 2017) are explicitly discussing either Japan or England; thus I wouldn't say that this caveat necessarily extends to the non-English and non-Japanese famines. Perhaps there were different mechanisms for the England famine and the European one and the European one was only started by Samalas while the English one was merely aggravated. Jo-Jo Eumerus (talk, contributions) 13:32, 13 January 2019 (UTC)

• and there had been issues with harvests already before the eruption[136] among other famine events it is the first well documented food crisis in England: what is meant by "among other famine events"? Can it just be cut?

  Yes, it's gone now. This sentence is in part meant to reflect the concern raised by Guillet 2017 that Samalas may not have been the sole cause. Jo-Jo Eumerus (talk, contributions) 20:44, 12 January 2019 (UTC)

• The famine occurred at a time of political crisis between King Henry III of England and the English magnates. I think this could be cut.

  Possibly, I think it was meant to contextualize the events of that year. Jo-Jo Eumerus (talk, contributions) 20:44, 12 January 2019 (UTC)

  OK. Mike Christie (talk - contribs - library) 12:06, 13 January 2019 (UTC)

• According to our article on flagellants, the first recorded incident is 1259, a data point that might be worth mentioning. This was in Italy, though, so you might combine "Europe" and "Byzantine Empire" into "Europe and the Near East". If you make it "Europe and Asia", and then "Americas", you'd have only two sections, rather than five, of which four are very short -- short sections are ugly.

  I've shuffled the paragraphs around a bit, how does it look now? Jo-Jo Eumerus (talk, contributions) 20:44, 12 January 2019 (UTC)

  Better. If it were me I'd try to find a way to group more sections together, but it's just a preference. Mike Christie (talk - contribs - library) 12:35, 13 January 2019 (UTC)

• The origins of the Flagellante movement may also be the social distress triggered by the eruption, but warfare and other plights: suggest (with the date as I proposed above, assuming you can reliably source it) "The Flagellante movement, which is first recorded in Italy in 1259, may have originated in the social distress caused by the effects of the eruption, though warfare and other causes..."

  Added something to that effect; Stothers gives 1260 as the start year and so do most of the sources that Google Scholar spits up. Jo-Jo Eumerus (talk, contributions) 20:44, 12 January 2019 (UTC)

• was the site of the so-called cliff dwellings: do we need "so-called"? Can we make it just "the site of cliff dwellings"?

  Going by sources on that term it appears to have a particular meaning in this context and is not just a generic dwelling below cliffs. Jo-Jo Eumerus (talk, contributions) 20:44, 12 January 2019 (UTC)

  OK, but "so-called" has slightly pejorative connotations. Given that we're not linking to these dwellings, I'd cut it, but I'll strike the point as it's not really wrong. Mike Christie (talk - contribs - library) 12:20, 13 January 2019 (UTC)

• This eruption[148] along with other volcanic eruptions during this period: suggest "The Samalas eruption was one of several during this period which may have triggered".

  Done. Jo-Jo Eumerus (talk, contributions) 20:44, 12 January 2019 (UTC)

• The application of rain-fed agriculture: suggest "use" instead of "application", unless there's some shade of meaning intended that I'm not seeing.

  Done. Jo-Jo Eumerus (talk, contributions) 20:44, 12 January 2019 (UTC)

• In Japan, the Mirror of the East chronicle from Azuma Kagami: our article indicates that these are the same thing, so perhaps we could cut "from Azuma Kagami" and link to it from Mirror of the East instead.

  Done. Jo-Jo Eumerus (talk, contributions) 20:44, 12 January 2019 (UTC)

• Other effects of the eruption include a total darkening of the Moon in May 1258 during a lunar eclipse: given that darkening the moon is what a lunar eclipse does, I think this needs to clarify how the eruption had an effect.

  According to Guillet 2017 at the same time chroniclers were reporting the presence of a "darkness" or a "fog"; such was also reported after the 1783 Laki eruption and it means that volcanic aerosols were shadowing the Earth and hiding the moon. The source seems to take it for granted that people will understand; let me see if I can find any explanation. This source suggests that such darkening of the Moon - which during a lunar eclipse is still illuminated by light coming from Earth - is often observed after volcanic eruptions. Jo-Jo Eumerus (talk, contributions) 20:44, 12 January 2019 (UTC)

  This is like the sea-level drop issue -- anything we can do to make it clearer to the reader is worth doing. Mike Christie (talk - contribs - library) 12:17, 13 January 2019 (UTC)

  Explained that a little; I am wondering if the reported complete darkening of the moon during a lunar eclipse on May 18th, 1258 (John de Taxter, 1265) which suggested the occurrence of abnormally high concentrations of stratospheric sulphate aerosols preventing incident sunlight being refracted and scattered into the shadow cone of the eclipse. The colour of an eclipsed moon is red under normal stratospheric conditions with background aerosolic loading (i.e. as experienced in August 31st, 1262) is an adequate source for volcanic aerosols reduce the amount of sunlight scattered into Earth's shadow and thus the brightness of the eclipsed Moon.. Jo-Jo Eumerus (talk, contributions) 13:32, 13 January 2019 (UTC)

  So long as it's clear that the sulfate aerosols mentioned in the source are of volcanic origin, I think that's fine. Mike Christie (talk - contribs - library) 15:15, 13 January 2019 (UTC)

-- Mike Christie (talk - contribs - library) 16:54, 12 January 2019 (UTC)

Climate effects

Just starting to look at this section. The stratospheric veils mentioned in the second paragraph seem to fit well with the social effects mentioned in the next section, which makes me wonder if this is the best organization. I can see this section is about the technical analysis and the next section is about the impact, which does seem reasonable. More comments when I've read the whole section. Mike Christie (talk - contribs - library) 12:40, 13 January 2019 (UTC)

I've read the section, but refrained from making any edits; I'm going to wait till the books I ordered arrive, in case they're relevant. The unit conversions are even uglier here than earlier, particularly for the tonnes -- you have 158,000,000 ± 12,000,000 tonnes (156,000,000 ± 12,000,000 long tons; 174,000,000 ± 13,000,000 short tons), for example, which could be written as "158 ± 12 megatonnes".

You might consider starting a peer review for this article; I think it would be benefit from more eyes. Mike Christie (talk - contribs - library) 15:38, 13 January 2019 (UTC)

I'll admit, I did use these large units deliberately to emphasize that they are large. Peer review, I am not fond of that due to its slow speed, but it sounds like a good idea for when I am waiting for the Allison Guyot FAC to conclude. Jo-Jo Eumerus (talk, contributions) 16:01, 13 January 2019 (UTC)

I take that the books haven't arrived yet? JoJo Eumerus mobile (talk) 14:03, 22 January 2019 (UTC)

One just arrived, the other did not yet. I should be able to look at the Medieval Warm Period one tonight or tomorrow. Mike Christie (talk - contribs - library) 14:24, 22 January 2019 (UTC)

The other showed up today, so I should have feedback tomorrow night. Mike Christie (talk - contribs - library) 00:03, 23 January 2019 (UTC)

Grove's Little Ice Age has a "causes" chapter which looks like the relevant bit for this article. I'm going through it now, but one thing I noticed immediately is that there's a chart of the acidity in the Crête core, which is taken from Hammer 1980 which I believe you have a copy of. Does he give the underlying data for the chart? I could reproduce it from the data -- it seems worthwhile because it shows the spikes from a bunch of known volcanoes, plus a couple of prominent spikes marked "Unknown", one of which is Samalas. Sometimes Nature papers have an accompanying "supporting data" section; the data might be in that. Mike Christie (talk - contribs - library) 00:50, 24 January 2019 (UTC)

Oh, and Grove is 1988 so I'm sure there will be no specific mention of Samalas; the only other thing I might find is speculation on whether volcanism triggered the LIA. Mike Christie (talk - contribs - library) 00:53, 24 January 2019 (UTC)

OK, I've looked through the chapter, and I don't think there's much there of use. One point is that you say increased sulfate concentrations were first found during the 1980s, but Grove cites this to Hammer 1980, so it must be no later than 1980. The relevant core was drilled in 1974 (and I can give you a cite for that if you need it). It wouldn't have been analyzed till some time after that, but I think you can safely say late 1970s. Grove says "The most active period volcanically came between AD 1250 and 1500 and between AD 1550 and 1700, suggesting that it had an important role in the causation of the Little Ice Age", but he concludes the chapter with a section that says volcanism's climatic impact "has yet to be substantiated conclusively", so this not a definite assertion. You cite two sources mentioning sulfate deposits in polar ice caps that precede the Crête core; do they give details? Mike Christie (talk - contribs - library) 01:11, 24 January 2019 (UTC)

Hammer 1980 does not itself give any data other than a list of spikes and it doesn't appear to have a "supporting data" section. For what it's worth Hamilton 2013 says "early 1980s" so they might actually mean Hammer 1980. As for You cite two sources mentioning sulfate deposits in polar ice caps that precede the Crête core; do they give details?, I don't think that there are any pre-Hammer 1980 sources cited or am I misunderstanding which sources you mean? Jo-Jo Eumerus (talk, contributions) 06:40, 24 January 2019 (UTC)

Is the spikes graph in three columns, with Samalas marked "Unknown" halfway down the middle column? If there's no supporting data section, I think it would be OK to reproduce all or part of the graph; there's nothing original about the design, so it's just data, which isn't copyrightable. It gives the reader a strong visual impression of how Samalas appeared in the ice core record before it was identified. Yes, Hamilton might mean Hammer 1980, but I'd at least take the "s" off "1980s".

Re the other point, you have "The sulfur deposits in the polar ice caps had already showed that climate disturbances reported in that time were due to a volcanic event, with the global spread indicating a tropical volcano as the cause,[1] although at first a source in a volcano near Greenland had been considered.[48]"; the two sources are Reid (2016) and Hamilton (2013). We discussed this further up this talk page, and you indicated there that Hamilton didn't go into details -- does Reid? Digging around, I found this which has a link to the supporting data for Lavigne (2013); it includes an English translation of the relevant bits of the Babad Lombok, and of some of the medieval chronicles. Quotes from those would add a bit of colour to the article -- what do you think?

There was nothing useful in the Medieval Warm Period book, by the way. Mike Christie (talk - contribs - library) 10:23, 24 January 2019 (UTC)

In order:

• I dunno about taking the graph, seems like "selection and arrangement" copyright might apply for even a nonoriginal graph. Last I checked commons:COM:TOO#US had nothing to say about graphs. I can't take the "s" in "1980s" out, the source does not specify the year.
• No dice; Reid 2016 isn't used in the article to discuss ice cores.
• Yes, taking some quotes from the Babad Lombok is a good idea. Jo-Jo Eumerus (talk, contributions) 17:10, 24 January 2019 (UTC)

Jo-Jo Eumerus (talk, contributions) 17:10, 24 January 2019 (UTC)

Also my archaeologist brother-in-law suggested looking at this, which I don't have access to but will request at RX tonight. Mike Christie (talk - contribs - library) 20:05, 24 January 2019 (UTC)

Now requested. Mike Christie (talk - contribs - library) 00:51, 25 January 2019 (UTC)

I also asked him about the data for the graph in Hammer 1980; he's an academic so I figured he'd know how to get it. He said when he's had this issue he's tried emailing the authors (Claus Hammer published as recently as 2012); or he's sometimes had to get calipers and measure the graph. Sigh. An email from Hammer would be no good to us as a source anyway. He also suggested looking in the NOAA palaeo ice core database, which would be here if it weren't for the government shutdown. Mike Christie (talk - contribs - library) 00:56, 25 January 2019 (UTC)

I'll see if I can get something done about Babad Lombok and the palaeo ice core database today. Jo-Jo Eumerus (talk, contributions) 06:48, 25 January 2019 (UTC)

Well, do you agree that the graph would be good to include? It's a lot of work to extract the data by measuring it, and it would be nice but is not really a requirement for this article. I got the requested article and just had a chance to glance it at; I think we can get a sentence out of it on the link between volcanism and climate though it's a relatively old paper to use as a survey. Mike Christie (talk - contribs - library) 12:34, 25 January 2019 (UTC)

Including a graph would indeed be good. Not necessarily that one though as it only refers to one ice core. Jo-Jo Eumerus (talk, contributions) 16:43, 25 January 2019 (UTC)

​Ok, so this is the weekend and I have more time. Let's see where we are:

• It seems like the government shutdown will end - or pause for a couple of weeks - so perhaps we can get the data for a graph soon.
• I've added a quote from Babad Lombok; I see that this book appears to be anonymous.
• Is there anything else amiss?

Jo-Jo Eumerus (talk, contributions) 10:37, 26 January 2019 (UTC)

I haven't really gone through the climate effects section for prose, so I'll do that today. I think that'll wrap it up; I would like more on the details of the research history but it seems pretty elusive. Mike Christie (talk - contribs - library) 15:35, 26 January 2019 (UTC)

I like the longer quote from the Babad Lombok, but you now have quotes in two places. Mike Christie (talk - contribs - library) 23:00, 26 January 2019 (UTC)

I don't think that's necessarily a problem. From Googling I get the impression that many people know of Samalas because of its impact in England, but it's really more important to Indonesia. Jo-Jo Eumerus (talk, contributions) 11:07, 27 January 2019 (UTC)

Climate effects 2

• When large scale volcanic eruptions inject aerosols into the atmosphere, they can form stratospheric veils, which reduce the amount of light reaching the surface. That reduces the temperatures on much of the Earth and can cause problems in agriculture including famine. The social effects of such events, however, are often reduced by the resilience of humans. Suggest "When large scale volcanic eruptions inject aerosols into the atmosphere, they can form stratospheric veils. These reduce the amount of light reaching the surface and cause colder temperatures, which can lead to poor crop yields." I would cut the last sentence; if we need it at all it belongs in the "Social and historical consequences" section.

  The source says This temporary disturbance of the world’s climate, often involving increased precipitation, can adversely affect agriculture. sure that that is a good representation thereof? Moved that other sentence down. Jo-Jo Eumerus (talk, contributions) 11:07, 27 January 2019 (UTC)

  I think it's OK -- any effect on agriculture that does not reduce crop yields isn't an adverse effect, so it's scarcely even a deduction. Mike Christie (talk - contribs - library) 11:30, 27 January 2019 (UTC)

  OK, did this then. Jo-Jo Eumerus (talk, contributions) 12:18, 27 January 2019 (UTC)

• Not all years with cold summers are linked to volcanic activity. Seems obvious, and not worth saying, unless I'm missing the intent here. Do you mean the reverse -- not all years with intense volcanic activity have caused cold summers?

  The reason I included that is because it's a commonly cited objection to theories about how volcanoes impact society. Jo-Jo Eumerus (talk, contributions) 11:07, 27 January 2019 (UTC)

  You mean people make the argument "volcanoes can't be the cause of any cold summers because some cold summers are not caused by volcanoes"? I don't think it's worth including, but if you do, I would make it clear that what it's addressing, and of course cite that. Mike Christie (talk - contribs - library) 11:30, 27 January 2019 (UTC)

  Took it out. Jo-Jo Eumerus (talk, contributions) 12:18, 27 January 2019 (UTC)

• scavenged is a nice metaphorical usage but we should probably be more direct since I'm having to guess what it means. I assume the halogens react with material in the eruption column and form compounds? So the bromine and chlorine are released in elemental form? That's surprising.

  The source is not very specific. There appear to be processes such as chlorine/bromine salts dissolving in waters that result in the scavenging. Yes, that is the normal term used for this process. Jo-Jo Eumerus (talk, contributions) 11:07, 27 January 2019 (UTC)

  Take a look in Google Books at pp. 28-29 of Holland & Turekian's Geochemistry of Earth Surface Systems; looks like it's HCl -> ClO that is the issue, for chlorine at least. Not much needs to be in the article, but if it's clear enough that HCl is what erupts and ClO is what causes the damage, that would be worth mentioning. Mike Christie (talk - contribs - library) 11:30, 27 January 2019 (UTC)

  Added a little thing about this. Jo-Jo Eumerus (talk, contributions) 12:18, 27 January 2019 (UTC)

• You don't refer to the halogen/ozone issue later in the section; if we're going to mention it in this section we should say what the effect on the climate was.

  Aye, that needs a better place (see comments on section, forthcoming). I think the issue is that the effects of a volcanically induced ozone hole aren't clear so it shouldn't be part of a climate section. Jo-Jo Eumerus (talk, contributions) 11:07, 27 January 2019 (UTC)

• I have to say I would be unable to support at FAC with the numeric data taking up so much space. It's ugly and distracting. I really think you should make it 223 ± 18 megatonnes. I would also get rid of the conversions to non-scientific units throughout; there's no need for them.

  I've stripped out the non-scientific units from that section, at first, and then expanded and modified these elsewhere. And replaced the long numbers with "million tons". IMO "megatonnes" makes one think of "megatons" which is a completely different concept. Jo-Jo Eumerus (talk, contributions) 11:07, 27 January 2019 (UTC)

  Thank you; that's much easier to read. Mike Christie (talk - contribs - library) 11:31, 27 January 2019 (UTC)

• We give the mechanism for summer cooling, but not for winter warming, and since it's introduced in a parenthesis it's a bit of a surprise to the reader. Then we say winters were long and cold, so the contradiction needs to be explained.

  That is a good question. As noted in this source there is some empirical evidence that certain parts of the world see warmer winters after volcanic eruptions but apparently it's mainly the far northern latitudes, not necessarily Europe. My personal impression is that the winter warming is a dynamic effect and thus context dependent, while the summer cooling is pretty much universal. Jo-Jo Eumerus (talk, contributions) 11:07, 27 January 2019 (UTC)

• Does the 2016 paper give enough detailed data that you can say how long the cooling lasted? Or enough to put in a small graph covering a decade or two around the eruption date?

  Um, which 2016 paper? There are several ones. Jo-Jo Eumerus (talk, contributions) 11:07, 27 January 2019 (UTC)

  Sorry, I meant Chikamoto et al, which you cite for the sea surface cooling. And looking at that paragraph again, I don't mean to restrict the comment to that source -- there are several numbers there, and it's a graphic-free section; could any of this data be presented graphically? Mike Christie (talk - contribs - library) 11:38, 27 January 2019 (UTC)

  This p.422 contains a graph; can you look at it? It sounds like it might come from NOAA and thus less problematic copyright wise. Jo-Jo Eumerus (talk, contributions) 12:18, 27 January 2019 (UTC)

• You say further on that the temperature changes may have lasted a decade; does that refer to sea surface temperatures or atmospheric temperatures too? If the latter I'd move that information to be next to the "More recent proxy data" one, since they're addressing the same data.

  Ocean temperature. Jo-Jo Eumerus (talk, contributions) 11:07, 27 January 2019 (UTC)

• According to earlier reconstructions: earlier than what? I think you simply mean that Oppenheimer 2003 predates Guillet et al 2017; if so I'd just give the dates.

  Added a date. Jo-Jo Eumerus (talk, contributions) 11:07, 27 January 2019 (UTC)

• and in the formation of deep water: what does this mean?

  Deep water is the downgoing branch of the thermohaline circulation. I took that mention out, though, because it contradicts the discussion on AMOC strength farther down and I suspect that the AMOC part is better grounded. This probably needs some more thought, however. Jo-Jo Eumerus (talk, contributions) 11:07, 27 January 2019 (UTC)

  Struck, since you've cut it; I guessed that was probably the meaning, but it seemed an odd phrase, though I wouldn't be surprised if you told me it was a common usage in the literature. Mike Christie (talk - contribs - library) 11:36, 27 January 2019 (UTC)

  Aye, it is a common phrase just not really clear for laypeople. Jo-Jo Eumerus (talk, contributions) 12:18, 27 January 2019 (UTC)

• Precipitation and evaporation both decreased as well, but the decrease of evaporation was stronger: suggest "Precipitation and evaporation both decreased, with evaporation reduced more than precipitation."

  Done. Jo-Jo Eumerus (talk, contributions) 11:07, 27 January 2019 (UTC)

Pausing here for the moment. Generally the section seems a bit choppy, going back and forth between the proxy signals and the effects, both recorded and modelled. Do you think it would help to have sections called "Paleoclimatic data" and "Climatic effects", instead of "Research history" and "Climatic effects"? Then all the information about the proxies could be put in the first section, and that could include the fact that it was not until 2013 that the proxy data was associated with Samalas. The second section could then be about the effects, without constantly pausing to introduce more data. This would also resolve the note above about ozone -- put it in the data section and there's no implication that it should have a climatic effect. Mike Christie (talk - contribs - library) 23:00, 26 January 2019 (UTC)

​It probably would help. The problem with the chlorine/bromine thing is that it's commonly discussed but it's not clear if it has climate implications - so it should probably go into a third section like "Simulated response of the Earth system" or a research section seems fine for me. As for the winter warming thing, there were apparently some places with cold winters and others with warm ones ... not sure how to best formulate that. Jo-Jo Eumerus (talk, contributions) 11:07, 27 January 2019 (UTC)

Fixes look good; some comments left above. Do you want to have a crack at changing the section structure next? I can try, but without the sources I'd have to be cautious. Mike Christie (talk - contribs - library) 11:41, 27 January 2019 (UTC)

I'll see if I can squeeze some time in between family obligations and User:Jo-Jo Eumerus/Coropuna to get that done. Jo-Jo Eumerus (talk, contributions) 11:43, 27 January 2019 (UTC)

​Took a stab at putting in a secondary section, I have a problem with the chlorine/bromine thing though: If I put them into a separate paragraph where does the "When large scale volcanic eruptions inject aerosols into the atmosphere, they can form stratospheric veils. These reduce the amount of light reaching the surface and cause colder temperatures, which can lead to poor crop yields." sentence go to? IMO, "Research history" should probably be a separate section, although it might be better off between the climate and history sections if we want to have a better flow. Jo-Jo Eumerus (talk, contributions) 12:18, 27 January 2019 (UTC)

Here's how you have it now:

• Aerosols & their effects
  • Ice cores - sulfates, thallium, comparisons to Tambora and Pinatubo
  • Aerosols - general comments, halogens, impact on ozone
  • Cooling impact -- temperatures
  • Cooling impact -- ice caps, sea ice, glaciers, NA oscillation, Baffin Island and Canada
  • End of MCA, other volcanoes, possible start of LIA, define LIA
• Simulated climate effects
  • Data from models, comparison to Pinatubo
  • List of other possible impacts
• Paleoclimatic data
  • Tree ring data
  • Atmospheric CO2
  • Modelling, effect on tree rings, details of models, El Nino
  • Unaffected regions

I still don't think this is the best order. The natural progression seems to me to be data, then impact. How about:

• Paleoclimatic data
  • Ice cores -- sulfates, thallium, comparisons
  • Tree ring data
  • Glacial advances, ice caps
  • Written records
• Modelled data
  • Halogens, atmospheric CO2
  • Modelled temperatures -- sea, atmosphere
• Climate effects
  • Possible end of MCA and start of LIA; other volcanoes
  • NA oscillation
  • List of other possible impacts
  • Unaffected regions

One issue here is how we present data such as "The Samalas eruption together with another eruption in the 14th century set off a growth of ice caps and sea ice" and related sentences. If this are unambiguously attributed to Samalas, with no caveats, they can be put in the climate effects section. If it's the other way round -- the ice growth is a proxy signal we're detecting and attributing to Samalas, in order to determine its effect on the climate, then it's data. Mike Christie (talk - contribs - library) 12:44, 27 January 2019 (UTC)

​That proposed sorting order seems good to me. As for the presentation of the ice sheet growth issue, my take is that this is not entirely uncontested; as noted in-text it is not 100% clear that the ice advance started with Samalas. When I wrote the article I did note explicit caveats; most claims didn't have any. Jo-Jo Eumerus (talk, contributions) 14:11, 27 January 2019 (UTC)

@Mike Christie: Did a reordering based on your suggestions; how does it look? Jo-Jo Eumerus (talk, contributions) 21:07, 28 January 2019 (UTC)

I think this reads much more naturally. I'm copyediting as I go; revert if you don't like anything -- I reworded a couple of sentences fairly substantially.

• How about moving the third para in "Aerosol..." to the "Simulated effects" section? It's about modelling, mostly. You could leave a note in the "Aerosol..." section that the tree ring data is inconsistent.
• Similarly, shouldn't the sentence about the NAO be moved down?
• I would still like to insert an explanation of winter warming after eruptions.

Overall this is much improved. I will do another read through of the whole article in the next couple of days, but I think the shape is right now. I still think you could combine the "research history" section with the "Aerosols..." section, but that's just personal preference, so it's fine if you like it the way it is. One more copyedit pass and that's probably it from me.

There is one outstanding point from above I'd like to raise again. Sorry to sound like a broken record, but you cite Reid (2016) for the last sentence in Increased sulfate concentrations were first found during the 1980s[48] in the Crête ice core (Greenland)[49] associated with a deposit of rhyolitic ash.[50] The sulfur deposits in the polar ice caps had already showed that climate disturbances reported in that time were due to a volcanic event, which makes it clear there are cores prior to Crête that had sulfate spikes. What does Reid cite for this? I have a fair number of ice core references and I'd like to look this up.

Other than that you might try Ceranthor or Awickert if you want another pair of eyes on it. Awickert hasn't been very active in years, but he used to do earth science FAC reviews, and his user page says to email him if you want feedback. Or just try PR, though it can be hit or miss there. Mike Christie (talk - contribs - library) 23:06, 28 January 2019 (UTC)

@Mike Christie:See, I was thinking of keeping the "sceptical" claims together when I wrote that section, especially since it's discussing a contrast between a modelled and an observed climate effect. Moved the NAO sentence down. Wrote a bit more about winter warming. Regarding Reid 2016, the sentence I wrote is supposed to say that the ice cores proved the volcanic origin of the event, not that there were other ice cores before Crête. I think a rewrite is needed there but I am not certain what to put in. Finally, regarding PR ... I don't think the Allison Guyot FAC will finish soon so I'll probably send it there anyhow. And ask these people (although I already asked Ceranthor about Coropuna and Huaynaputina ... the latter though will probably end up resembling the Samalas article, so why not) Jo-Jo Eumerus (talk, contributions) 07:18, 29 January 2019 (UTC)

I've had a go at the Reid sentence -- see what you think. The other points are fine. One more suggestion: Increased sulfate concentrations were first found during the 1980s[48] in the Crête ice core (Greenland)[49] associated with a deposit of rhyolitic ash.[50] We talked about this above; Hammer (1980) reports it, so 1980s seems insufficiently precise, though as you pointed out it's not inaccurate. How about "Increased sulfate concentrations were first found in the Crête ice core drilled in Greenland in 1974, which were reported in 1980 to be associated with a deposit of rhyolitic ash"? I think the date of the core is worth working in, and since we have the date of Hammer's paper we might as well give it exactly. If you need a source for the 1974 date, this will work:

• Langway, Chester C. (2008). "The history of early polar ice cores" (PDF). Cold Regions Science and Technology. 52: 101–117.

I think the article is in pretty good shape now. I'll read it through again when it gets to FAC and no doubt I'll find something to complain about, but it's just about there. You know what would make an interesting featured topic? The volcanoes that cause the spikes in that graph in Hammer 1980. Which reminds me, I want to look for that data on the NOAA website, if it's open again. I'll let you know if I find it. Mike Christie (talk - contribs - library) 12:26, 29 January 2019 (UTC)

@Mike Christie: So as long as it's properly referenced (Hamilton 2013 does say "1980s" so it can't be the reference for another date) that change is fine. It looks like the NOAA website is working again...for now, although I think we want a different link. Jo-Jo Eumerus (talk, contributions) 16:52, 29 January 2019 (UTC)

@Mike Christie: Doubleping as I've installed that proposed rewrite now. I'll also start that peer review. Jo-Jo Eumerus (talk, contributions) 21:32, 29 January 2019 (UTC)

Potential image sources

• https://ijog.geologi.esdm.go.id/index.php/IJOG/article/view/311/209 Jo-Jo Eumerus (talk, contributions) 17:47, 9 July 2019 (UTC)

Some sources for further consideration

Some sources could be used which need a second opinion however:

• https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018MS001566: I am not sure if it concludes that the eruption increased or decreased the organic carbon content of Earth.
• https://www.tandfonline.com/doi/abs/10.1080/0035919X.2018.1555680 (freely available from ResearchGate): It does state (based on the conclusion of others) that Samalas did not cause the famines, but I know plenty of sources here cited that say otherwise and I am not sure if the "others" have been interpreted correctly.
• http://estudiosgeol.revistas.csic.es/index.php/estudiosgeol/article/view/982: Mostly a question whether the eruption list here ought to be supplemented with info from that source.

Jo-Jo Eumerus (talk, contributions) 17:49, 9 July 2019 (UTC)

Additional ones:

• https://journals.ametsoc.org/doi/full/10.1175/JCLI-D-19-0348.1: Not sure how this should be formulated.
• https://www.tandfonline.com/doi/full/10.1080/16000889.2019.1633848: It's a bit unclear if it talks about a computer model or a paleoclimate record.
• https://link.springer.com/article/10.1007/s00382-019-04807-z, https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2019JD030864 and https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/joc.5955: Not sure if this should be cited in the tree rings sections.
• https://hal.archives-ouvertes.fr/hal-02178554/: Probably the most questionable, as its claim that the 1257 eruption did not have significant cooling effects seems to be contradicted by many other sources and it also reads a bit like a climate change denial publication.
• Google Books: This one proposes a redating of the eruption to before 1257, but it has not caught on yet.
• https://www.sciencedirect.com/science/article/pii/S0277379119304123: A challenge to the theory that the Samalas eruption kick-started the LIA.

Jo-Jo Eumerus (talk) 14:47, 11 December 2019 (UTC)