Wikipedia

December 2023 Mindanao earthquake

On December 2, 2023, at 22:37 PST (14:37 UTC), a moment magnitude (Mww ) 7.6 earthquake occurred off the island of Mindanao in the Philippines. The shallow subduction earthquake killed at least three people and left 79 injured.[3]

December 2023 Mindanao earthquake
Damaged PAGASA Doppler weather radar station in Hinatuan.Map
December 2023 Mindanao earthquake is located in Philippines
December 2023 Mindanao earthquake
UTC time2023-12-02 14:37:04
ISC event636143719
USGS-ANSSComCat
Local dateDecember 2, 2023
Local time22:37
Magnitude7.6 Mww
7.4 Mw
Depth40.0 km (24.9 mi)
Epicenter8°31′37″N 126°24′58″E / 8.527°N 126.416°E / 8.527; 126.416
TypeOblique-thrust
Total damage₱1.2 billion (US$22.8 million)[1]
Max. intensityMMI VII (Very strong)

PEIS VII (Destructive)
Tsunami64 cm (2.10 ft)
Aftershocks8,403 (425 above Mw 4.5, as of 29/12/2023)[2]
Strongest is Mw 6.9
Casualties3 dead, 79 injured

Tectonic setting

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See also: Subduction tectonics of the Philippines

The Philippine Trench which runs east of the Philippine islands represents a major subduction zone where the Philippine Sea plate subducts westwards. At its southern portion, it runs north–south from the eastern coast of Mindanao to the northern part of Halmahera Island.[4] The convergence rate along the trench varies from 3.2–5.4 cm (1.3–2.1 in) per year. Large earthquakes occurring along the Philippine Trench are limited in records although two large earthquakes were recorded in 1897 (Ms  7.3) and 1924 (Ms  8.2) with little seismological characteristics known. Some large intraslab earthquakes have been associated with the trench including the Mw  7.6 normal-faulting earthquake of 1975 and a reverse-faulting Mw  7.6 shock in 2012.[5] The segment involved in the 2023 earthquake was associated with a magnitude 7.5 earthquake in 1921 which produced a tsunami.[6]

Earthquake

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Strong ground motion map produced by the United States Geological Survey
 
Map of main shock and aftershocks – M 4.0 or greater (map data)

The United States Geological Survey reported the earthquake had a magnitude of 7.6 and a maximum Modified Mercalli intensity of VII (Very strong).[7] The Philippine Institute of Volcanology and Seismology (PHIVOLCS) said it had a magnitude of 7.4 and that it measured VII (Destructive) on the PHIVOLCS earthquake intensity scale in Tandag.[8]

The earthquake occurred as a result of shallow oblique-thrust faulting likely along the subduction interface of the Philippine Trench. At this location, the Philippine Sea plate moves west-northwest at a rate of about 103 mm (4.1 in) per year with respect to the Sunda plate. A finite fault model suggests rupture occurred around an elliptical area measuring 80 km × 80 km (50 mi × 50 mi). Maximum slip was concentrated around the epicenter, although slightly up-dip, which was estimated at up to 1.8 m (5 ft 11 in).[7]

PHIVOLCS recorded 8,403 aftershocks,[3] and within 27 days of the earthquake, 425 aftershocks above Mw 4.5 were recorded by the USGS; the aftershock sequence occurred southeast of the mainshock.[2] The largest aftershock, measuring 6.9 struck on December 4, occurring north of the aftershock sequence[9] near Cagwait. However, PHIVOLCS said that it was a separate earthquake.[10] On August 2, 2024, two Mww 6.8 and 6.3 earthquakes occurred within the area of the 2023 sequence.[11][12]

The December 2 earthquake was described as the first major earthquake in the area since a doublet 7.1 and 7.5 earthquake that also produced a tsunami in 1992.[13]

Tsunami

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Tsunami warnings were issued by PHIVOLCS for the provinces of Surigao del Sur and Davao Oriental,[14] while NHK said tsunami waves up to 1 m (3.3 ft) could hit Japan's southern coast.[15] The Pacific Tsunami Warning Center also said that they expected tsunami waves to be as high as 1–3 m (3.3–9.8 ft) in the Philippines, 0.3–1 m (0.98–3.28 ft) in Palau, and less than 0.3 m (0.98 ft) in American Samoa, China, South Korea, a majority of Polynesia, Melanesia and Micronesia, Hawaii, Indonesia, Japan, Taiwan and Malaysia.[16] The tsunami threat prompted thousands of residents of Ishigaki, Miyako Island, and Futtsu in Japan to evacuate.[17]

In the Philippines, a 64 cm (2.10 ft) high tsunami was observed on Mawes Island.[18] In Davao City, the tsunami reached 8 cm (3.1 in), and in Lawigan, Bislig, it reached 18 cm (7.1 in).[19][20] A tsunami of 2 cm (0.79 in) was also recorded in Legazpi.[21]

In Japan, the tsunami reached a height of 40 cm (1.3 ft) in Hachijō-jima[22] and 20 cm (0.66 ft) in Kushimoto in Wakayama Prefecture, and Tosashimizu in Kōchi Prefecture.[23] It also reached a height of 1 cm (0.39 in) at Malakal Island, Palau.[19]

Impact

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Collapsed building in Hinatuan, Surigao Del Sur

Three deaths were recorded;[24] one in Tagum, one in Barobo[25] and another in Bislig. The deaths were attributed to collapsing concrete walls.[26][25] Seventy-nine people were injured,[3] including twelve in Davao Region.[27][28] Additionally, 8,315 houses were partially damaged, and 390 were destroyed,[3] costing ₱44 million (US$810,000). Total damage was estimated to be worth ₱133 million (US$2.4 million).[29] At least 399,765 people from 100,174 families were affected, including 100,533 residents who were left homeless,[30] while Surigao del Sur governor Alexander Pimentel ordered the suspension of classes in the affected areas until December 6[25] and cancelled all Christmas parties in government offices to encourage donations instead.[31]

In Hinatuan, only 12 km (7.5 mi) south of the epicenter, 142 houses collapsed, 852 others were damaged[30] and power outages occurred.[32] The town's mayor said 11,000 families, equivalent to 41,000 people were affected, with mud contamination forcing some residents to boil water.[33] A Doppler weather radar monitoring tower in the town operated by the Philippine Atmospheric, Geophysical and Astronomical Services Administration was assessed as "structurally unsafe" after sustaining large cracks[34] and was further sealed off due to its vulnerability to liquefaction.[35] The Enchanted River, the town's main tourist attraction, was closed following a landslide near the area, resulting in losses of at least P200,000 in revenues.[36] The municipal government also reported that damage to housing and infrastructure was estimated at ₱98 million.[25] The town was subsequently placed under a state of calamity.[37]

Minor damage occurred in Butuan, Surigao, Sayak, Tandag and Bislig Airports.[38] Ten houses collapsed and 448 others were damaged in Agusan del Sur,[3] where power was knocked out across the entire province. In Bayugan, two buildings were damaged,[30] including a wall collapse at a store.[39] Several houses and bridges, as well as a mosque were damaged, power outages occurred and people fainted due to the earthquake in Davao City.[40][32] Patients were evacuated from a hospital in Butuan[41] and a fire broke out in another hospital due to a short circuit.[29] At least 62 houses were destroyed and 1,147 others were damaged in Bislig.[42] Liquefaction destroyed five houses in Gingoog, Misamis Oriental.[43] In Monkayo, Davao de Oro, eight people were injured by a landslide, five houses collapsed and 2,436 others were damaged.[3]

See also

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References

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  1. ^ "Situation Report No. 18 for the Magnitude 7.4 and 6.8 Earthquake in Hinatuan, Surigao del Sur" (PDF). National Disaster Risk Reduction and Management Council. December 17, 2023. Retrieved December 19, 2023.
  2. ^ a b "USGS earthquake catalog". United States Geological Survey. Archived from the original on December 3, 2023. Retrieved December 3, 2023.
  3. ^ a b c d e f "Situation Report No. 18 for the Magnitude 7.4 and 6.8 Earthquake in Hinatuan, Surigao del Sur" (PDF). National Disaster Risk Reduction and Management Council. December 17, 2023. Retrieved December 19, 2023.
  4. ^ Fan, Jianke; Zhao, Dapeng (2018). "Evolution of the Southern Segment of the Philippine Trench: Constraints From Seismic Tomography". Geochemistry, Geophysics, Geosystems. 19 (11): 4612–4627. doi:10.1029/2018GC007685.
  5. ^ Ye, Lingling; Lay, Thorne; Kanamori, Hiroo (2012). "Intraplate and interplate faulting interactions during the August 31, 2012, Philippine Trench earthquake (Mw 7.6) sequence". Geophysical Research Letters. 39 (24). doi:10.1029/2012GL054164.
  6. ^ Cabato, Luisa (December 3, 2023). "Phivolcs: Movement in PH trench caused 7.4-magnitude quake in Hinatuan". INQUIRER.net. Archived from the original on December 3, 2023. Retrieved December 3, 2023.
  7. ^ a b National Earthquake Information Center (December 2, 2023). "M 7.6 – Mindanao, Philippines". United States Geological Survey. Archived from the original on December 2, 2023. Retrieved December 2, 2023.
  8. ^ "Magnitude 7.4 quake rocks Mindanao, over 370 aftershocks recorded". NDBC News. December 2, 2023. Archived from the original on December 3, 2023. Retrieved December 2, 2023.
  9. ^ National Earthquake Information Center (December 3, 2023). "M 6.9 – Mindanao, Philippines". United States Geological Survey. Retrieved December 3, 2023.
  10. ^ "Magnitude 6.8 quake hits Surigao del Sur, Phivolcs says not an aftershock". CNN Philippines. December 4, 2023. Archived from the original on December 5, 2023. Retrieved December 5, 2023.
  11. ^ ANSS. "M 6.8 – 19 km E of Barcelona, Philippines 2024". Comprehensive Catalog. U.S. Geological Survey.
  12. ^ ANSS. "M 6.3 – 36 km E of Barcelona, Philippines 2024". Comprehensive Catalog. U.S. Geological Survey.
  13. ^ "Surigao earthquake on Dec. 2 'first major' quake in Mindanao since 1992". ABS-CBN. December 4, 2023. Retrieved December 5, 2023.
  14. ^ "Tsunami warning raised in Surigao del Sur, Davao Oriental after M6.9 quake". ABS-CBN. December 2, 2023. Archived from the original on December 3, 2023. Retrieved December 2, 2023.
  15. ^ "Quake triggers Philippines, Japan tsunami warnings". RTHK. December 2, 2023. Archived from the original on December 3, 2023. Retrieved December 2, 2023.
  16. ^ National Oceanic and Atmospheric Administration (December 2, 2023). "TSUNAMI MESSAGE NUMBER 2". Pacific Tsunami Warning Center. Archived from the original on December 2, 2023. Retrieved December 2, 2023.
  17. ^ "Tsunami threat recedes after Philippines earthquake". dw.com. Archived from the original on December 3, 2023. Retrieved December 3, 2023.
  18. ^ "Tsunami Advisory and Warning". PHIVOLCS. December 2, 2023. Archived from the original on November 17, 2023. Retrieved December 2, 2023.
  19. ^ a b National Oceanic and Atmospheric Administration (December 2, 2023). "TSUNAMI MESSAGE NUMBER 3". Pacific Tsunami Warning Center. Archived from the original on December 2, 2023. Retrieved December 2, 2023.
  20. ^ Adel, Rosette. "Tsunami warning lifted after Magnitude 7.4 quake strikes off Surigao del Sur". The Philippine Star. Retrieved December 4, 2023.
  21. ^ 日本放送協会 (December 3, 2023). "フィリピン沖地震「ミンダナオ島で8センチの津波観測」米NOAA". NHKニュース. Archived from the original on December 3, 2023. Retrieved December 3, 2023.
  22. ^ "Tsunami waves of 40 cm in Japan after Philippines earthquake: Agency". Al Jazeera. December 2, 2023. Archived from the original on December 3, 2023. Retrieved December 2, 2023.
  23. ^ "Japan lifts tsunami warning after strong quake jolts Philippines". The Japan Times. December 3, 2023. Archived from the original on December 3, 2023. Retrieved December 3, 2023.
  24. ^ "Powerful aftershocks continue to rattle parts of Philippines after magnitude 7.6 earthquake kills 3". Fox Weather. December 5, 2023. Retrieved December 5, 2023.
  25. ^ a b c d "P98.4-M quake damage in Hinatuan, Surigao Sur". SunStar Davao. December 5, 2023. Retrieved December 5, 2023.
  26. ^ Krishnasai, C., ed. (December 3, 2023). "Pregnant woman among two dead, nine missing, and 529 families affected in Philippines earthquake". WION. Archived from the original on December 3, 2023. Retrieved December 3, 2023.
  27. ^ ECHO (December 5, 2023). "Philippines – Earthquake, update (UN OCHA, GDACS, NDRRMC, DROMIC DSWD) (ECHO Daily Flash of 5 December 2023)". ReliefWeb. Retrieved December 6, 2023.
  28. ^ Gutierrez, P., ed. (December 3, 2023). "1,726 aftershocks felt after Surigao quake; OCD validating 2 deaths". ABS-CBN News. Retrieved December 3, 2023.
  29. ^ a b "Philippines: 7.4 Earthquake Hinatuan, Surigao Del Sur – Flash Update No.1, As of 03 December2023, 7 p.m. local time". ReliefWeb. December 3, 2023. Archived from the original on December 3, 2023. Retrieved December 3, 2023.
  30. ^ a b c "DSWD DROMIC Report #2 on the Mw 7.4 Earthquake Incident in Hinatuan, Surigao del Sur as of 04 December 2023, 6PM". ReliefWeb. December 5, 2023. Retrieved December 6, 2023.
  31. ^ "After major quake, Kabayan spares Surigao del Sur but aftershocks remain". ABS-CBN News. December 19, 2023. Retrieved December 19, 2023.
  32. ^ a b "Surigao del Sur magnitude 7.4 earthquake causes damage to houses, infra". GMA News. December 2, 2023. Archived from the original on December 3, 2023. Retrieved December 2, 2023.
  33. ^ "11,000 families in Hinatuan affected by strong Surigao quake: mayor". ABS-CBN. December 4, 2023. Retrieved December 5, 2023.
  34. ^ "PAGASA's Doppler radar in Hinatuan among those damaged by quake". ABS-CBN. December 5, 2023. Retrieved December 5, 2023.
  35. ^ "Two PAGASA weather radars damaged by earthquakes". ABS-CBN. December 7, 2023. Retrieved December 7, 2023.
  36. ^ "Damaged homes, absent tourists: Hinatuan confronts quake damage, livelihood impact". ABS-CBN. December 6, 2023. Retrieved December 6, 2023.
  37. ^ "Aside from fear, quake victims begin to feel fatigue from repeated aftershocks". ABS-CBN. December 6, 2023. Retrieved December 6, 2023.
  38. ^ "CAAP reports on status of Mindanao airports following quake". Journal. December 2, 2023. Archived from the original on December 3, 2023. Retrieved December 2, 2023.
  39. ^ "Strong earthquake that sparked tsunami warning leaves one dead in Philippines". Eastern Daily Press. December 3, 2023. Archived from the original on December 3, 2023. Retrieved December 3, 2023.
  40. ^ "Mga tao sa mall at gusali sa Davao City, nagsilabasan dahil sa lindol". ABS-CBN. December 2, 2023. Archived from the original on December 3, 2023. Retrieved December 2, 2023.
  41. ^ Nimoni, Fiona (December 3, 2023). "Philippines earthquake: Pregnant woman killed by Mindanao quake". BBC News. Archived from the original on December 2, 2023. Retrieved December 3, 2023.
  42. ^ "SitRep No. 07 for the Magnitude Mw7.4 and Mw6.8 Earthquakes in Surigao Del Sur" (PDF). NDRRMC. Retrieved December 10, 2023.
  43. ^ "SitRep no. 02 re Magnitude 7.4 Earthquake in Hinatuan, Surigao del Sur" (PDF). NDRRMC. December 5, 2023. Retrieved December 6, 2023.
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