July 2019 Cotabato earthquake

Last updated
July 2019 Cotabato Earthquake
Philippines relief location map (Mindanao).svg
Bullseye1.png
Philippines relief location map (square).svg
Bullseye1.png
UTC  time2019-07-09 12:36:58
USGS-ANSS ComCat
Local dateJuly 09, 2019
Local time8:36:58 PM PST
Duration20-30 sec
Magnitude5.6 Mw
Depth10.0 km (6.2 mi)
Epicenter 6°48′50″N125°07′08″E / 6.814°N 125.119°E / 6.814; 125.119 Makilala, Cotabato
FaultMakilala Fault
Typestrike-slip
Areas affectedMindanao
Total damageA grand total of 106 Schools, 119 Houses, and 14 other Infrastructures damaged after the strong shaking.
Max. intensity VI (Strong)
PEIS – VI (Very Strong)
TsunamiNone
LandslidesNone
ForeshocksNone
AftershocksSome, Strongest - 5.3 Mw
Casualties1 dead, 73 injured

On 9 July 2019, at 8:36 PM (PST), an earthquake measuring Mw 5.6 jolted the province of North Cotabato, [1] Davao del Sur, and other nearby provinces. The National Disaster Risk Reduction and Management Council reported one dead and three injured in Makilala after the earthquake, [2] and a total of 164 families affected in Cotabato Province. Near the epicenter of the earthquake (8 km W of Makilala, Cotabato), the severity of strong ground motion was assigned VI (Strong) on the Modified Mercalli intensity scale. [1] A total of 106 schools, 119 houses, and 14 other infrastructures were damaged by the earthquake. [2]

Contents

Tectonic setting

The Philippine islands were formed in evolutionary processes involving subductions, collisions, and strike-slip faulting. Earthquakes are frequent there as a result of collision processes between the Philippine Sea Plate (PSP) and the Sunda Plate (SP). The slip convergence between PSP and the SP boundary is obliquely accommodated by the Philippine fault system, which is a major left-lateral strike-slip fault system. The Philippine fault has been slipping at a rate of 33 ± 11 mm/yr in the northern and central Leyte sections. The southern part of the Philippine fault is mainly located in eastern Mindanao and constitutes a complex fault system with discrete strands and splays. Mindanao island is located on the complex collision boundary between the SP and the PSP. Some parts of the convergence between these plates are consumed by the Philippine fault and subduction at the Cotabato trench. Some other parts of the convergence are accommodated by the fault system in Mindanao, and a series of strike-slip faults have developed.

Earthquake and aftershocks

The earthquake was measured Mw 5.6 by the Philippine Institute of Volcanology and Seismology and European-Mediterranean Seismological Centre at a shallow depth of 10 km, with the epicenter located at 06.83°N, 125.02°E. [1]

The maximum intensity was recorded as VI on the Modified Mercalli Intensity Scale (MMI) and also on PHIVOLCS Earthquake Intensity Scale (PEIS). The focal mechanism indicated strike-slip movement on the Makilala Fault. [1]

There were moderately strong aftershocks ranging Magnitude 4.0 +, yet there were no foreshocks before the event. The strongest aftershock rocked Cotabato and Davao del Sur the day after the main event. It was recorded at Mw 5.3 by USGS and Mw 5.0 by PHIVOLCS; it was a perceived V (Moderately Strong) earthquake on the PHIVOLCS Earthquake Intensity Scale and VI on the Modified Mercalli intensity scale by the United States Geological Survey. It was initially thought to be a separate event but was reclassified as a moderately strong aftershock. In Davao del Sur, many students fainted and lost consciousness after the tremor, forcing class suspensions. Over 70 people were injured. This was the first strong earthquake that happened in Cotabato and Davao del Sur for the past years. [3]

The earthquake occurred in a region within a faulting zone known as the Cotabato fault system, which is a seismically active region due to the presence of several active faults, including the NW-SE trending Makilala-Malungon, M'lang, North and South Columbio and Tangbulan faults, and the SW-NE trending Makilala and Balabag faults. These faults may work with subduction zones to accommodate different components of regional tectonic strain in the slip partitioning system caused by the relative motion between the PSP and SP. Characterizing the geometrical complexity of these source faults has great significance for understanding the seismotectonic implications of the large earthquakes occurring in Mindanao. [4]

Damage and casualties

Macroseismic Intensity Shakemap of the Jul 09 2019 Cotabato Earthquake Macroseimic Intensity Shakemap of the Makilala Earthquake.jpg
Macroseismic Intensity Shakemap of the Jul 09 2019 Cotabato Earthquake

The place where the most damage was reported was in the small town of Makilala, Cotabato, in which more than 100 homes were damaged and one person was killed. Three additional individuals suffered injuries. [2] There was also damage in Kidapawan City. Many infrastructures and homes were partially damaged in Kidapawan. Damage was also observed in Davao del Sur (Magsaysay, Matanao, Bansalan, and Digos). Tulunan, M'lang, Antipas, and Matalam in Cotabato. Central Mindanao was most affected in the earthquake. [3]

See also

Related Research Articles

<span class="mw-page-title-main">Mount Apo</span> Dormant volcano in the Philippines

Mount Apo, also known locally as Apo Sandawa, is a large solfataric, dormant stratovolcano on the island of Mindanao, Philippines. With an elevation of 2,954 meters (9,692 ft) above sea level, it is the highest-mountain in the Philippine Archipelago, Mindanao and 24th-highest peak of an island on Earth. Located on the tripartite border of Davao City and Davao del Sur in the Davao Region, and Cotabato in Soccsksargen, Mount Apo is the most-prominent mountain in the Philippines. The peak overlooks from Davao City 45 kilometers (28 mi) to the northeast, Digos 25 kilometers (16 mi) to the southeast, and Kidapawan 20 kilometers (12 mi) to the west. It is a protected area and a Natural Park of the Philippines.

<span class="mw-page-title-main">Earthquake swarm</span> Series of localized seismic events within a short time period

In seismology, an earthquake swarm is a sequence of seismic events occurring in a local area within a relatively short period. The time span used to define a swarm varies, but may be days, months, or years. Such an energy release is different from the situation when a major earthquake is followed by a series of aftershocks: in earthquake swarms, no single earthquake in the sequence is obviously the main shock. In particular, a cluster of aftershocks occurring after a mainshock is not a swarm.

<span class="mw-page-title-main">Kidapawan</span> Capital of Cotabato, Philippines

Kidapawan, officially the City of Kidapawan, is a 3rd class component city and capital of the province of Cotabato, Philippines. According to the 2020 Census, it has a population of 160,791 people.

<span class="mw-page-title-main">1976 Moro Gulf earthquake</span> Earthquake in the Philippines

The 1976 Moro Gulf earthquake and tsunami occurred on August 17, 1976, at 00:11 local time near the islands of Mindanao and Sulu, in the Philippines. It measured 8.0 on the moment magnitude scale occurring at a depth of 20 km (12 mi). The earthquake was accompanied by a destructive tsunami that resulted in a majority of the estimated 5,000 to 8,000 fatalities. It was the deadliest and strongest earthquake in the Philippines in 58 years since the 1918 Celebes Sea earthquake.

The Philippine Fault System is a major inter-related system of geological faults throughout the whole of the Philippine Archipelago, primarily caused by tectonic forces compressing the Philippines into what geophysicists call the Philippine Mobile Belt. Some notable Philippine faults include the Guinayangan, Masbate and Leyte faults.

The 2017 Surigao earthquake occurred on February 10, 2017, at 10:03 PM (PST), with a surface wave magnitude of 6.7 off the coast of Surigao del Norte in the Philippines. According to the PHIVOLCS Earthquake Intensity Scale the earthquake was an Intensity VII (Destructive) earthquake at maximum. In the past Surigao province has been hit by a magnitude 7.2 tremor in both 1879 and 1893.

<span class="mw-page-title-main">Davao–Cotabato Road</span> Road in the Philippines

The Davao–Cotabato Road is a 205.7-kilometer (127.8 mi), two-to-six lane major national primary road, connecting the provinces of Davao del Sur, Maguindanao del Sur, Cotabato, and Maguindanao del Norte. It runs from Davao City to Sultan Kudarat, Maguindanao del Norte.

The 2019 Cotabato earthquakes were an earthquake swarm which struck the province of Cotabato on the island of Mindanao in the Philippines in October 2019. Three of these earthquakes were above 6.0 on the moment magnitude scale with a Mercalli intensity of VIII. More than 40 people have been reported dead or missing and nearly 800 were injured as a result of these events.

At 14:11 PST on December 15, 2019, the province of Davao del Sur on the island of Mindanao in the Philippines was struck by an earthquake measuring 6.8 Mw. It had a maximum perceived intensity of VII on the Modified Mercalli Intensity Scale. At least 13 people were killed and another 210 injured.

The 1990 Bohol earthquake occurred on February 8, 1990 at 15:15:32 which had a magnitude of 6.8 Mw . The earthquake had a moderate depth of 25.9 km (16 mi). Most of the damage was observed in the province of Bohol. A tsunami hit the southeastern coastline of Bohol and the island of Camiguin. There were 6 deaths, over 200 injuries and an estimated ₱157 million in total damage reported.

The 1990 Carlentini earthquake occurred off the Sicilian coast, 20 km east northeast from the town of Augusta, Sicily on 13 December at 01:24 local time. The moderately-sized earthquake measuring 5.6 on the moment magnitude scale (Mw ) resulted in the deaths of 19 people and caused at least 200 injuries. It also inflicted significant damage in the region, leaving 2,500 homeless.

On February 7, 2021, at 12:22 PM PST, an earthquake measuring Mw  6.0 struck Davao del Sur and Cotabato. The event registered a Modified Mercalli Intensity Scale (MMI) of VIII (Severe) with VII on the PHIVOLCS Earthquake Intensity Scale (PEIS).

On August 12, 2021, at 01:46:12 PST, a strong Mw  7.1 earthquake struck the island of Mindanao at a depth of 56.7 kilometers (35.2 mi). It perceived Intensity V on the PHIVOLCS Earthquake Intensity Scale. No damage or injuries were reported but a young man was killed by the earthquake.

On June 19, 1988, 20:19:52 UTC, an earthquake measuring 6.2 Mw struck the central Philippine island of Mindoro. The quake struck in the early morning at a depth of 16.7 km. It had a maximum intensity of VI (Strong) on the Modified Mercalli intensity scale, and was located 1 km north-northeast of Bagong Sikat. The focal mechanism indicated strike-slip faulting. Most of the damage was in Mindoro where two people died and four were injured.

The 1879 Surigao earthquake occurred on June 30 at 18:38 02:55 local time on the northeastern tip of Mindanao. The earthquake with a moment magnitude (Mw ) of 7.4 struck with an epicenter just south of Lake Mainit. Extensive damage occurred but there were no reports of casualties.

The 1955 Lanao earthquake struck Lanao del Sur on April 1 at 02:17 local time. The earthquake measuring 7.4 on the moment magnitude scale and assigned a maximum intensity of VIII (Severe) on the Modified Mercalli intensity scale was one of the largest to hit Mindanao. It caused immense damage around Lake Lanao and the southern reaches of the Visayan islands. It killed at least 465 individuals and injured a further 898.

<span class="mw-page-title-main">2022 Luzon earthquake</span> Earthquake in the Philippines

On July 27, 2022, at 8:43:24 a.m. (PHT), an earthquake struck the island of Luzon in the Philippines. The earthquake had a magnitude of 7.0 Mw , with an epicenter in Abra province. Eleven people were reported dead and 615 were injured. At least 35,798 homes, schools and other buildings were damaged or destroyed, resulting in ₱1.88 billion (US$34 million) worth of damage.

<span class="mw-page-title-main">November 2023 Mindanao earthquake</span> Magnitude 6.7 earthquake in the Philippines

At 16:14 PST on November 17, 2023, the province of Sarangani on the island of Mindanao in the Philippines was struck by an earthquake measuring 6.7 Mww. It had a maximum perceived intensity of VIII (Severe) on the Modified Mercalli Intensity Scale. At least eleven people were killed and another 730 were treated for injuries.

<span class="mw-page-title-main">December 2023 Mindanao earthquake</span> Magnitude 7.6 earthquake in the Philippines

On December 2, 2023, at 22:37 PST, a magnitude 7.4-7.6 earthquake occurred off the island of Mindanao in the Philippines. The shallow subduction earthquake killed at least three people and left 79 injured.

References

  1. 1 2 3 4 "M 5.6 - 8 km W of Dolo, Philippines". earthquake.usgs.gov. U.S. Geological Survey. Retrieved 26 August 2021.
  2. 1 2 3 "Earthquake Information re Magnitude 5.6 Earthquake in Makilala (North Cotabato)_". ndrrmc.gov.ph. National Disaster Risk Reduction and Management Council. 13 July 2019. Retrieved 26 August 2021.
  3. 1 2 Aftershock (2019-07-10). "Earthquake: 70 Students Hurt In Stampede Caused By Aftershock". Philippine News. Retrieved 2021-08-26.
  4. Bingquan Li; Yongsheng Li; Wenliang Jiang; Zhe Su; Wenhao Shen (2020). "Conjugate ruptures and seismotectonic implications of the 2019 Mindanao earthquake sequence inferred from Sentinel-1 InSAR data". International Journal of Applied Earth Observation and Geoinformation. 90 (102127): 102127. Bibcode:2020IJAEO..9002127L. doi: 10.1016/j.jag.2020.102127 .