The 2017 Batangas earthquakes were an

earthquake swarm 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 f ...

that occurred from early April to mid-August 2017, affecting the province of

Batangas Batangas, officially the Province of Batangas ( tl, Lalawigan ng Batangas ), is a province in the Philippines located in the Calabarzon region on Luzon. Its capital is the city of Batangas, and is bordered by the provinces of Cavite and La ...

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 ...

and other nearby areas. The first major earthquake occurred on April 4 at 8:58pm

Philippine Standard Time Philippine Standard Time (PST or PhST; fil, Pamantayang Oras ng Pilipinas), also known as Philippine Time (PHT), is the official name for the time zone used in the Philippines. The country only uses one time zone, at an offset of UTC+08:00, b ...

, with a

surface wave magnitude The surface wave magnitude (M_s) scale is one of the magnitude scales used in seismology to describe the size of an earthquake. It is based on measurements of Rayleigh surface waves that travel along the uppermost layers of the Earth. This ma ...

of 5.5 off the coast of Batangas. According to the

PHIVOLCS Earthquake Intensity Scale The PHIVOLCS Earthquake Intensity Scale (PEIS) is a seismic scale used and developed by the Philippine Institute of Volcanology and Seismology (PHIVOLCS) to measure the intensity of earthquakes. It was developed as upon a specific response to t ...

, the earthquake had an intensity of VII (Very Strong). On April 8, stronger earthquakes occurred in the province. The PHIVOLCS recorded the strongest earthquake later that afternoon that had a surface wave magnitude of 6.0. Another earthquake struck on August 11, with a surface wave magnitude of 6.3. Three years later, Taal Volcano, about 25 kilometers from the epicenter, erupted after 43 years of inactivity.

Earthquakes

April 4 earthquake

The quake was recorded by PHIVOLCS on April 4, 2017 at 8:58 PM (UTC+8). Based on that record, the epicenter of the 5.5 earthquake was located 7 kilometers northwest of

Tingloy Tingloy, officially the Municipality of Tingloy ( tgl, Bayan ng Tingloy), is a 5th class municipality in the province of Batangas Batangas, officially the Province of Batangas ( tl, Lalawigan ng Batangas ), is a province in the Philippine ...

, Batangas. The earthquake was of tectonic origin. Metro Manila and nearby provinces felt shaking at Intensity 3 while

Obando, Bulacan Obando, officially the Municipality of Obando ( tgl, Bayan ng Obando), is a 2nd class municipality of the Philippines, municipality in the Philippine Province, province of Bulacan, Philippines. According to the 2020 census, it has a population ...

felt Intensity 4, and Batangas City experienced Intensity 6 shaking. The earthquake is suspected to be the caused by the movement of the Lubang Fault. At 1:00 pm on April 7, PHIVOLCS stated that they have recorded 934 aftershocks; 118 of which were plotted and while 14 were reportedly felt. The Pacific Tsunami Warning Center announced no tsunami warning following the earthquake.

April 8 earthquakes

Two earthquakes occurred near the towns of Mabini and Tanauan on April 8. PHIVOLCS recorded the first earthquake which occurred near Mabini at 3:07 pm as having a surface wave magnitude of 5.6 while the second earthquake which happened in Talaga Proper, Mabini, Batangas, at 3:09 pm was recorded as having a surface wave magnitude of 6.0. The

United States Geological Survey The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...

(USGS) recorded the first as a magnitude 5.7 earthquake while the second as a moment magnitude of 5.9 earthquake.

August 11 earthquake

PHIVOLCS recorded the earthquake which occurred at 1:28 pm as having a surface wave magnitude of 6.3. The

(USGS) recorded the earthquake as a moment magnitude of 6.2 earthquake.

Shocks

Shakemap Earthquake 8 April 2017 Mindoro Philippines

Earthquakes with at least magnitude 5 as recorded by PHIVOLCS:

Impact

Damages on some buildings, resorts and houses have been reported. The Basilica of Saint Martin of Tours or Taal Basilica, which is considered to be the largest Roman Catholic Church in Asia and located in

Taal, Batangas Taal (), officially the Municipality of Taal ( tgl, Bayan ng Taal), is a 3rd class municipality of the Philippines, municipality in the Philippine Province, province of Batangas, Philippines. According to the 2020 census, it has a populatio ...

, sustained damage during the April 4 earthquake. The April 8 earthquakes caused concrete blocks to fall from the church facade. The Basilica of the Immaculate Conception Church in

Batangas City Batangas City, officially the City of Batangas ( fil, Lungsod ng Batangas), is a 1st class component city and capital of the province of Batangas, Philippines. According to the 2020 census, it has a population of 351,437 people. Batangas City i ...

also sustained damage on its walls during the April 8 quake. The Batangas Provincial capitol also sustained damaged from the April 4 earthquake. The initial estimated cost of damage to the building was . On April 5, the Batangas provincial government declared a

state of calamity A state of emergency is a situation in which a government is empowered to be able to put through policies that it would normally not be permitted to do, for the safety and protection of its citizens. A government can declare such a state du ...

. Six people were injured by the 8 April quake. Around 14,000 people were temporarily relocated in evacuation centers. During his installation on April 21, 2017, Lipa Archbishop Gilbert Garcera ordered Father Aurelio Oscar Dimaapi to temporarily close the Minor Basilica of the Immaculate Conception in order to prevent injuries. In the aftermath of the August 11 tremor, many students were disturbed since the tremor struck during class hours. Several schools suspended classes after the earthquake. So far, no damage has been reported.

Power

The earthquake also damaged several power plants supplying the Luzon Grid, like one generator unit of the Ilijan Power Plant, one unit of Avion Power Plant, all units of Santa Rita Combined Cycle Power Plant, and one unit of San Lorenzo Combined Cycle Power Plant, resulting to a loss of 2,584 MW. The switchyard of San Lorenzo Power Plant was damaged and a

transmission tower A transmission tower, also known as an electricity pylon or simply a pylon in British English and as a hydro tower in Canadian English, is a tall structure, usually a steel lattice tower, used to support an overhead power line. In electrical gri ...

was toppled also by the earthquakes. As a result, the power supply reserve for Luzon decreased, leading the

National Grid Corporation of the Philippines The National Grid Corporation of the Philippines (NGCP) is a privately owned corporation that was created on January 15, 2009, through RA 9511. It is a consortium of three corporations, namely Monte Oro Grid Resources Corporation, Calaca High Po ...

to place the Luzon Grid on "yellow" alert on April 10 and 11, and the

Department of Energy A Ministry of Energy or Department of Energy is a government department in some countries that typically oversees the production of fuel and electricity; in the United States, however, it manages nuclear weapons development and conducts energy-rel ...

ordered immediate repair of power plants damaged. A policy to protect the grid from earthquake damage is being drafted by the Department of Energy after the quakes.

References

Notes

External links

* {{Earthquakes in the Philippines Batangas earthquake Batangas earthquake Earthquakes in the Philippines History of Batangas History of Metro Manila Batangas earthquake Earthquake clusters, swarms, and sequences