Published December 2022 | Version v2
Presentation Open

Fault geometry and geologic impacts of the 15 December 2019 magnitude 6.9 Davao del Sur earthquake

Authors/Creators

  • 1. Department of Science and Technology - Philippine Institute of Volcanology and Seismology

Contributors

Contact person:

  • 1. Department of Science and Technology – Philippine Institute of Volcanology and Seismology

Description

After a series of magnitude (M) 6 earthquakes in the provinces of Cotabato and Davao Del Sur in October 2019 (M6.3 on 16 October, M6.6 and M6.1 on 29 October, and M6.5 on 31 October), another magnitude 6 earthquake occurred in this area on 15 December 2019. This earthquake has the largest magnitude (M6.9) with the epicenter located further to the southeast of the October 2019 earthquakes. Based on the epicenter of the earthquake, documented earthquake damages, aftershock distribution, results of satellite image analysis and focal mechanism solution, the causative fault for this earthquake is the Makilala-Malungon Fault. A part of the Cotabato Fault System, this sinistral, NW-SE trending fault is 65-km-long traversing the provinces of Cotabato, Davao del Sur, and Sarangani. The ground shaking was felt maximum at intensity VII using the PHIVOLCS Earthquake Intensity Scale (PEIS) VII, characterized as destructive, in most of the municipalities in Davao del Sur. Damages to buildings and infrastructures were documented in areas that experienced PEIS VI (very strong) and PEIS VII (destructive). Liquefaction manifested as lateral spreads, sand boils and fissures were observed in the municipalities of Padada, Kiblawan, Hagonoy, Matanao, and Magsaysay in Davao del Sur. Mass wasting manifested as landslides, slumps, rockslides, tension cracks, rockfall, and earthflow were documented in the provinces of Davao del Sur, Sarangani, and Sultan Kudarat. Liquefaction and mass wasting also caused significant damage to buildings and infrastructures. Based on the National Disaster Risk Reduction and Management Council (NDRRMC) situational report number 15, the earthquake affected more than 80,000 families, 13 deaths, and 210 persons were injured.

Files

1_GeoCon_DavaodelSurEarthquake_abstact_JSPerez_02Dec2020.pdf

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