The 2019 Eastern Samar Earthquake struck the islands of

Visayas The Visayas ( ), or the Visayan Islands (Bisayan languages, Visayan: ''Kabisay-an'', ; tl, Kabisayaan ), are one of the three Island groups of the Philippines, principal geographical divisions of the Philippines, along with Luzon and Mindanao ...

in the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

on April 23, 2019 at 1:37:51 PM(PHT).It had a

moment magnitude The moment magnitude scale (MMS; denoted explicitly with or Mw, and generally implied with use of a single M for magnitude) is a measure of an earthquake's magnitude ("size" or strength) based on its seismic moment. It was defined in a 1979 pape ...

of 6.5 and a

local magnitude The Richter scale —also called the Richter magnitude scale, Richter's magnitude scale, and the Gutenberg–Richter scale—is a measure of the strength of earthquakes, developed by Charles Francis Richter and presented in his landmark 1935 ...

of 6.2 with a max intensity of VI based on the PHIVOLCS Earthquake Intensity Scale(PEIS). The epicenter was in

San Julian, Eastern Samar San Julian, officially the Municipality of San Julian ( war, Bungto han San Julian; tl, Bayan ng San Julian), is a 5th class municipality in the province of Eastern Samar, Philippines. According to the 2020 census, it has a population of 14,800 ...

and the

hypocenter In seismology, a hypocenter or hypocentre () is the point of origin of an earthquake or a subsurface nuclear explosion. A synonym is the focus of an earthquake. Earthquakes An earthquake's hypocenter is the position where the strain energy s ...

was at a depth of 64 km(~39.76 mi). As of April 30, 2019 there were 172

aftershocks In seismology, an aftershock is a smaller earthquake that follows a larger earthquake, in the same area of the main shock, caused as the displaced crust adjusts to the effects of the main shock. Large earthquakes can have hundreds to thousand ...

ranging from magnitudes of 1.6 to 4.6. The earthquake injure 48 people and damaged about 245 homes.

Eastern Samar Eastern Samar (Waray-Waray: ''Sinirangan Samar''; tl, Silangang Samar), officially the Province of Eastern Samar, is a province in the Philippines located in the Eastern Visayas region. Its capital is the city of Borongan. Eastern Samar occupies ...

is located near an active

subduction zone Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...

, the

Philippine trench The Philippine Trench (also Philippine Deep, Mindanao Trench, and Mindanao Deep) is a submarine trench to the east of the Philippines. The trench is located in the Philippine sea of the western North Pacific Ocean and continues NNW-SSE. It has a ...

, where the

Philippine Sea plate The Philippine Sea Plate or the Philippine Plate is a tectonic plate comprising oceanic lithosphere that lies beneath the Philippine Sea, to the east of the Philippines. Most segments of the Philippines, including northern Luzon, are part of ...

subducts beneath the

Sunda plate The Sunda Plate is a minor tectonic plate straddling the Equator in the Eastern Hemisphere on which the majority of Southeast Asia is located. The Sunda Plate was formerly considered a part of the Eurasian Plate, but the GPS measurements have ...

, and movement along the trench is what caused the earthquake. The earthquake struck less than a day after another magnitude 6.1 earthquake in

Luzon Luzon (; ) is the largest and most populous island in the Philippines. Located in the northern portion of the Philippines archipelago, it is the economic and political center of the nation, being home to the country's capital city, Manila, as ...

, but it was found that these earthquakes were unrelated.

Geography of the Philippines

The Visayas Islands are located in the central part of the Philippines consisting of seven main islands that make up its land. Their topography is full of tall mountains and large plains that provide the cultivation of sugarcane and rice. Their location in the Visayas sea provides fishing opportunities for the island to obtain more food in a sustainable way. Common produce also grown here includes maize, coconuts, bananas, tobacco, and various root crops. The location of these islands is one of the most seismically active due to the subduction zones the Philippines sits on. The multiple trenches indicate the many subduction zones around the Philippines creating these large magnitude earthquakes. The Philippines itself is right next to the

that is subducting underneath the Sunda Plate on the Eastern shore of the country.

Earthquake Details

Mainshock

Although the earthquake happened a day after an earlier earthquake struck Luzon, the state agency has stated that the Visayas earthquake is unrelated to the prior earthquake. The Visayas earthquake was determined to be caused by the movement of the

Philippine Trench The Philippine Trench (also Philippine Deep, Mindanao Trench, and Mindanao Deep) is a submarine trench to the east of the Philippines. The trench is located in the Philippine sea of the western North Pacific Ocean and continues NNW-SSE. It has a ...

. The movement at the trench was specifically the Philippine Sea plate subducting below the neighboring plate, releasing seismic energy. There was no tsunami because the earthquake occurred on land and deep underground. Forty-eight people were injured, most of them slightly by falling objects, and slight damage was reported near the epicenter. The

Leyte Provincial Capitol The Leyte Provincial Capitol was the seat of government of the Philippine province of Leyte (province), Leyte until 2019. The historic building situated in Tacloban also served as the temporary national capitol in 1944 to 1945 during the World Wa ...

Tacloban Tacloban ( ; ), officially the City of Tacloban ( war, Syudad han Tacloban; fil, Lungsod ng Tacloban), is a first class highly urbanized city in the Eastern Visayas region of the Philippines. The city is autonomous from the province of Leyte, a ...

sustained damage which led to the provincial government abandoning the building in May 2019, with the intention of converting the building into a museum. “''It was really very strong. at first it was moderate until 5 seconds it appears to be every infrastructure are shaking, including the basketball court that was beside our house, and even while running outside the house to look for safer ground. i myself can”-'' English translation of someone who was in Calbayog, reporting what was felt during the earthquake in their location.

Intensity

Aftershocks

This earthquake had an estimated 172 aftershocks(As of April 30, 2019) that were in many different places around Samar over the next several days, 6 of which were felt. These ranged from magnitudes of 1.6 to 4.6 with slight shaking as seen from the commenters. While it was technically possible that another earthquake of a higher magnitude could have occurred at this same location, it was extremely unlikely and did not end up happening, confirming that the 6.5 M_w event was the mainshock. Aftershocks could also be felt all the way in India according to this commentor: "''I was sleeping it is 1:50am in India and i was awakened by the earthquake. My neighbors ran outside and waited for sometime until the earthquake stopped."''

Damages

Many of the buildings near the epicenters were not built properly to withstand high magnitude earthquakes; things like tiles fell off of the ceilings and walls if they were not secured enough. A total of 245 houses were damaged with one of them fully destroyed. Along with the damaged buildings a lot of power outages occurred the day of the earthquake which was then restored within 24-hours.

References

{{Earthquakes in the Philippines 2019 disasters in the Philippines 2019 earthquakes Earthquakes in the Philippines April 2019 events in the Philippines