April 1923 Kamchatka earthquake and tsunami

On April 13, 1923 at 15:31 UTC, an earthquake occurred off the northern coast of the Kamchatka Peninsula in the USSR, present-day Russia. The earthquake had a surface-wave magnitude (Ms ) of 6.8–7.3 and an estimated moment magnitude (Mw ) of 7.0–8.2.[5][1] This event came just two months after a slightly larger earthquake with an epicenter struck south of the April event. Both earthquakes were tsunamigenic although the latter generated wave heights far exceeding that of the one in February.[6] After two foreshocks of "moderate force", the main event caused considerable damage.[5] Most of the 36 casualties were the result of the tsunami inundation rather than the earthquake.[7]

April 1923 Kamchatka earthquake
Map of the Kamchatka Krai. Epicenter marked as a bullseye.
UTC time1923-04-13 15:31:07
ISC event911331
Local dateApril 14, 1923 (1923-04-14)
Local time02:31
Magnitude6.8–7.3 Ms,[1] 7.0–8.2 Mw[2][3][4]
Depth15 km
Epicenter56°34′N 163°02′E / 56.56°N 163.03°E / 56.56; 163.03
Areas affectedKamchatka, USSR (present-day Russia)
Max. intensityMMI X (Extreme)
TsunamiUp to 30 meters
Casualties36 dead

Tectonic setting edit

The earthquake occurred off the Kamchatka Peninsula's east coast, which runs parallel to the Kuril-Kamchatka Trench, the area where the Pacific and Okhotsk Sea plates converge. Being older and therefore denser, the Pacific subducts beneath the Kamchatka Peninsula, which sits on the Okhotsk Sea Plate. These two plates meet along a convergent boundary, marked by the trench. The subduction zone is seismogenic and produces Kamchatka earthquakes, which occasionally generate tsunamis; some of these megathrust earthquakes are very strong (such as the 1952 magnitude 9.0 earthquake, the 5th largest ever recorded).[8]

Earthquake edit

The April earthquake was part of a sequence of megathrust earthquakes on the Kamchatka Peninsula, which began in February. On February 3, a magnitude 8.4 earthquake, whose hypocenter was 15 km deep,[9] resulted in extreme shaking assigned XI (Extreme) on the Modified Mercalli intensity scale and caused a tsunami with run-ups of 6 meters.[10][11] It was followed by a magnitude 7.4 aftershock the same month.[12]

The International Seismological Centre placed the April earthquake magnitude at 6.8 Ms  or 7.0 Mw ,[4][13] while the NGDC and some older studies placed it at 7.3–7.4 Mw . Beno Gutenberg and Charles Richter assigned the event a magnitude of 7.2 Ms .[12] A 2004 reevaluation of earthquakes in the region revised the earthquake magnitude to 8.2 Mw, based on analyzing the associated tsunami.[2][3] It was not considered an aftershock of the February earthquake because it ruptured another segment of the subduction zone.[12]

Location edit

The epicenter coordinates of this earthquake differ across sources and journals. The International Seismological Summary placed this at 55.7°N, 162.5°E, while the ISC-GEM Catalogue lists this event as having an epicenter at 56.36° N 162.70° E.[13][6] Meanwhile, Beno Gutenberg and Charles Richter suggested the epicenter location to be 56.5° N, 16.5° E.[14] In a 2017 study, Salaree and Okal argued it was located 110 km to the north, at 57.35° N, 162.91° E, which is northwest of Bering Island.[6] In another study by Bourgeois and Pinegina published in 2018, the source area of the April earthquake is north of the February rupture but southwest of Bering Island and in Kamchatka Bay [ru].[3] On the other hand, E.R. Engdahl's relocation places the epicenter coordinates at 56.56°N, 163.03°E, inside the Kamchatskiy Peninsula and close to the ISC-GEM coordinates.[6][13]

Characteristic edit

The earthquake rupture displayed features analogous to that of a tsunami earthquake,[6] which generates locally destructive tsunamis with higher run-up heights. A notable feature that makes such events unique is the release of seismic energy which happens at long periods. The release of long-period seismic energy in turn results in moderately strong to no shaking along the coast during these earthquakes. Damage patterns of tsunami earthquakes solely from shaking have been mostly smaller than expected for its size. As a result, local communities usually would have little to no advanced natural warning for when a tsunami hit.[12] Tsunami earthquakes have slower than usual rupture velocities, which could be as slow as 1 km/s. The rupture propagates up-dip along with the shallow subduction interface towards the trench, generating tsunamis.[15] The tsunamis generated by these earthquakes are significantly disproportionate for its surface wave magnitude as a consequence.[6]

Tsunami edit

Salaree and Okal suggested that apart from the slow rupture velocity, an earthquake-triggered submarine landslide is thought to have generated the unusually high local tsunami run-ups.[6] The presence of subaerial landslides near elevated shorelines after the earthquake was also evidence of landslide-triggering tsunamis. The landslide tsunami model also satisfactorily reproduced the tsunami height distribution.[6] A survey of the affected region discovered high run-up heights at 20–30 meters.[16] The tsunami affected a stretch of coastline from Cape Shubert to Cape Kamchatskiy of the Kamchatka Bay.

A 1961 paper stated that the first tsunami wave, which was described as small, arrived at Ust-Kamchatsk 15 minutes after the earthquake.[17] Approximately fifteen minutes later, an 11-meter-high wave began advancing onshore. The second wave was destructive, washing away structures at a nearby settlement and flowing as far as 7 km up the Kamchatka River from its mouth,[17] being able to do so because it inundated over a coastal plain covered by a layer of thick ice. Together with the snow, it smoothened the low-lying coastal plains, allowing the tsunami to reach and cause damage far inland.

West of the Kamchatka River, the tsunami waves were reported to be higher, with run-up measuring 20–30 meters, far higher than the tsunami generated by the larger February earthquake.[6][18][17] The Japanese-owned fish canneries and villages were totally destroyed.[19] A small cutter belonging to the Nichiro cannery was found at a location 1–2 km inland at a height of 30 meters.

The extent of damage decreased significantly eastwards along a 10 km portion of a spit that separates Lake Nerpichye from the Kamchatka Gulf. On the spit, a cannery was completely destroyed. A newer cannery and radio station at the same location had moderate damage only. The tsunami at this location, Perevoloka, was approximately one meter high.[18]

Other locations edit

A maximum run-up height of 4 meters was recorded at Bering Island but the exact location where it was measured is unknown.[7] On the Hawaiian Islands, the tsunami was recorded 30 cm at Hilo, 20 cm at Honolulu and 8 cm at Tofino. On the United States west coast, a 15 cm wave was recorded at San Francisco while at the Port of Los Angeles, some swirls were observed between 06:00 am and 10:00 am.[6] A weak tsunami was also recorded along the Japanese coast.[19]

Damage and aftermath edit

Before the mainshock, a sequence of foreshocks was felt for four hours, keeping the residents on high alert. Two noticeable foreshocks occurred on 13 April at 21:00 and 14 April at 01:00 local time respectively. They were felt with light to moderate intensities, causing hanging items to sway slightly.[20]

The earthquake struck at 02:00 am local time on the 14th of April. Its reported intensity was as high as X (Extreme) on the Modified Mercalli intensity scale.[5] A local newspaper reported that many barns and dilapidated houses were destroyed. More than 230 animals perished, including dogs, cows, and pigs.[19] Residents in towns and villages were driven out of their homes when the earthquake shook. The tremors knocked hanging photographs, dishes on shelves, and stoves to the floor. It also cracked the windows of many homes.[20]

The tsunami killed 36 people along the coast of Kamchatka.[19] Twenty-three of those killed were in Ust-Kamchatsk, of which there were 13 Japanese and five Russian and Chinese victims. Along the coasts, the tsunami tore off trees by the roots.[19] A small Japanese boat was also deposited some 30 meters on top of a raised beach. At the time, the boat was occupied by a Japanese couple and when the tsunami struck, one of them was killed.[19]

After the earthquake and tsunami, many survivors relocated to other villages upstream to avoid a similar disaster.[19] Cherny Yar and Nizhnekamchatsk were among the villages that survivors moved into because they were situated far inland and safe from future tsunamis. Some of the remaining inhabitants of Ust-Kamchatsk later founded the small village of Krutoberegovo [ru] because the tsunami had badly affected the main city.[21] Others remained in the city to reconstruct the damaged city.[22]

The Los Angeles Times on 15 April reported that flooding in the Korean of city Busan caused over 1,000 deaths.[6] Meanwhile the Sydney Morning Herald on 16 April claimed that 400 people went missing due to a tidal wave in the same city. The news article also stated that the total number of people that perished was unknown, but believed to be large.[23] Further analysis however, concluded that the Busan flooding occurred approximately 24 hours before the earthquake and is, therefore, an unrelated event.[6]

See also edit

References edit

  1. ^ a b N. V. Kondorskaya; N. Shebalin; Y. A. Khrometskaya (1982). A. Gvishiani (ed.). New catalog of strong earthquakes in the U.S.S.R. from ancient times through 1977. Boulder, Colorado: World Data Center A for Solid Earth Geophysics. p. 455. Retrieved 12 June 2021.
  2. ^ a b Gusev, A. A.; Shumilina, L.S. (2004). "Recurrence of Kamchatka strong earthquakes on a scale of moment magnitudes" (PDF). Physics of the Solid Earth. 40: 206–215. Archived from the original (PDF) on 5 July 2022.
  3. ^ a b c Bourgeois, Joanne; Pinegina, Tatiana K. (2018). "The 1997 Kronotsky earthquake and tsunami and their predecessors, Kamchatka, Russia" (PDF). Natural Hazards and Earth System Sciences. 18 (1): 335–350. Bibcode:2018NHESS..18..335B. doi:10.5194/nhess-18-335-2018. Retrieved 5 June 2021.
  4. ^ a b ISC (2022), ISC-GEM Global Instrumental Earthquake Catalogue (1904–2018), Version 9.0, International Seismological Centre
  5. ^ a b c "Comments for the Significant Earthquake RUSSIA: NEAR KAMCHATKA". ngdc.noaa.gov. NCEI. Retrieved 5 June 2021.
  6. ^ a b c d e f g h i j k l Salaree, A., Okal, E.A. (2017). "The "Tsunami Earthquake" of 13 April 1923 in Northern Kamchatka: Seismological and Hydrodynamic Investigations" (PDF). Pure and Applied Geophysics. 175 (4): 1257–1285. doi:10.1007/s00024-017-1721-9. S2CID 134560632. Retrieved 5 June 2021.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  7. ^ a b "Comments for the Tsunami Event KAMCHATKA". earthquake.usgs.gov. USGS. Retrieved 5 June 2021.
  8. ^ "20 Largest Earthquakes in the World". www.usgs.gov. Retrieved 2021-06-20.
  9. ^ "M 8.4 – near the east coast of the Kamchatka Peninsula, Russia". earthquake.usgs.gov. USGS. Retrieved 6 June 2021.
  10. ^ "Comments for the Tsunami Event". NGDC/WDS Tsunami Event Database. National Geophysical Data Center. Retrieved 8 June 2021.
  11. ^ "Comments for the Significant Earthquake". Significant Earthquake Database. National Geophysical Data Center. Retrieved 8 June 2021.
  12. ^ a b c d Emile A. Okal, José C. Borrero (2011). "The 'tsunami earthquake' of 1932 June 22 in Manzanillo, Mexico: seismological study and tsunami simulations". Geophysical Journal International. 187 (3): 1443–1459. Bibcode:2011GeoJI.187.1443O. doi:10.1111/j.1365-246X.2011.05199.x.
  13. ^ a b c "Event 911331 Near east coast of Kamchatka Peninsula". International Seismological Centre Online Event Bibliography. International Seismological Centre. Retrieved 6 June 2021.
  14. ^ Gutenberg, B., & Richter, C. F. (1954). Seismicity of the Earth and associated phenomena. Princeton, NJ: Princeton University Press.{{cite book}}: CS1 maint: multiple names: authors list (link)
  15. ^ Fukao, Yoshio (1979). "Tsunami earthquakes and subduction processes near deep-sea trenches". Journal of Geophysical Research. 84 (B5): 2303–2314. Bibcode:1979JGR....84.2303F. doi:10.1029/JB084iB05p02303.
  16. ^ Troshin, A. N., & Diagilev, G. A. (1926). "The Ust' Kamchatsk earthquake of April 13, 1923". Library Institute Physics Earth (in Russian). Moscow, Russia: USSR Academy of Sciences.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  17. ^ a b c Soloviev, S.L. and Ferchev, M.D. "Summary of data on tsunamis in the USSR". Bulletin of the Counsel on Seismology (in Russian). USSR Academy of Sciences, Moscow.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  18. ^ a b Zayakin, Y., & Luchinina, A. (1987). "Catalogue of Tsunamis on Kamchatka". Vniigmi-MTSD (in Russian).{{cite journal}}: CS1 maint: multiple names: authors list (link)
  19. ^ a b c d e f g Borisov V.I. (2002). "Forgotten Tragedy". kamchatsky-krai.ru (in Russian). Retrieved 5 June 2021.
  20. ^ a b Sergeeva, A. A. Godzikovskaya, L.P. Zabarinskaya. "CATALOG OF MACROSEISMIC DESCRIPTIONS AND INSTRUMENTAL MATERIALS OF EARTHQUAKES IN KAMCHATKA DURING THE EARLY INSTRUMENTAL OBSERVATION PERIOD 1900–1951". Institution of the Russian Academy of Sciences Geophysical Center RAS: World Data Center for Solid Earth Physics. Retrieved 6 June 2021.{{cite web}}: CS1 maint: multiple names: authors list (link)
  21. ^ "95th anniversary of Krutoberyogov". Ust-Kamchatka municipal district. 24 September 2018. Archived from the original on 6 June 2021. Retrieved 6 June 2021.
  22. ^ "Ust-Kamchatsk, Kamchatka". Kamchatkaland. Retrieved 6 June 2021.
  23. ^ "Tidal wave. 400 Persons Missing". New South Wales, Australia: The Sydney Morning Herald. 16 April 1923.

External links edit