The Negros Trench is an oceanic trench located northeast of the Sulu Trench and west of Negros Island Region in Visayas, the trench is located in the Sunda Plate in the southwestern region of the Pacific Ocean. The depth of the Negros Trench is unknown, in contrast it's neighboring trench the Sulu Trench has a depth of 5,600. During the Early-Miocine, the Sunda Plate subducted below the Philippine Mobile Belt,[10] which would later form the Negros Trench.

The Negros Trench 50-100 kilometers west of Visayas, The Sulu Trench in the southwest, Manila Trench west-northwest, and the Philippine Trench in the east
Negros Trench is located in Visayas
1922
1922
1925
1925
1948
1948
1950
1950
1951
1951
1990
1990
2011
2011
2012
2012
2014
2014
Epicenters of large earthquakes ≥ 6.4 Mw along the Negros Trench, from 1922[1] 1925[2] 1948[3] 1950[4] 1951[5] 1990[6] 2011[7] 2012[8] 2014[9]

Background

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The Negros trench was formed from subduction of the Eurasian Plate underneath the Philippine Sea plate which initiated during the Early Miocene (23.03-20.44 million years ago), The trench was previously the site of a collision zone with the Palawan plate, which formed the Philippine Trench 8–9 million years ago, This trench is located west of the Visayan Islands. This trench moves 2–3 cm/year.

Although there are vast areas of subduction zones, some authors have considered this region to have low seismic activity. There has been a decent amount of earthquakes with a magnitude ≥6.4 in the region, with the most recent occurring in 2011. It hit the trench in a depth of 19.0 km. Areas adjacent to the subduction zones have experienced large seismic activity.

Seismicity

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Year Location Moment magnitude Depth Casualties
1922 west of Looc 6.5 15.0 km -
1925 north of Nalundan 6.7 15.0 km 17
1948 north-northeast of Buga 7.8 15.0 km 74
1950 south-southeast of San Nicolas 6.5 25.0 km -
1951 west-northwest of Linaon 6.5 25.0 km 1
1990 east-southeast of Union 7.1 18.1 km 8
2011 west-southwest of Cayhagan 6.4 19.0 km -
2012 north-northeast of Jimalalud 6.7 11.0 km 51–113
2014 west-southwest of Alim 6.3 15.5 km -

References

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  1. ^ "M 6.5- Luzon, Philippines". United States Geological Survey.
  2. ^ "M 6.7 - Visayas, Philippines". United States Geological Survey.
  3. ^ "M 7.8 -Visayas, Philippines". United States Geological Survey.
  4. ^ "M 6.7 -Visayas, Philippines". United States Geological Survey.
  5. ^ "M 6.5 -Visayas, Philippines". United States Geological Survey.
  6. ^ "M 7.1 -Visayas, Philippines". United States Geological Survey.
  7. ^ "M 6.4-Visayas, Philippines". United States Geological Survey.
  8. ^ "M 6.7 -Visayas, Philippines". United States Geological Survey.
  9. ^ "M 6.3-Negros, Philippines". United States Geological Survey.
  10. ^ "Journal of Geophysical Research: Solid Earth". AGU Journals. Retrieved 2022-03-10.