STRONG TREMORS. Twin earthquakes strike Batangas on April 8, 2017. Photo courtesy of Ryan Valle

MANILA, Philippines (7th UPDATE) – Twin earthquakes rocked Metro Manila and nearby provinces on Saturday afternoon, April 8.

The Philippine Institute of Volcanology and Seismology (Phivolcs) said a magnitude 5.6 quake first struck at 3:07 pm, off Mabini, Batangas. The United States Geological Survey (USGS) put it at 5.7.

Epicenter of first earthquake. Image courtesy of Phivolcs

The first quake was then followed by a magnitude 6.0 tremor at 3:09 pm, also in the same area, according to Phivolcs. USGS earlier said this tremor had a magnitude of 5.9.

Epicenter of second earthquake. Image courtesy of Phivolcs

The recorded intensities for the two quakes are exactly the same.

Intensity VII – Mabini, Batangas

Intensity VI – Calatagan, Nasugbu, and Tingloy, Batangas

Intensity V – Batangas City, Sto Tomas, and Lemery, Batangas; Tagaytay City

Intensity IV – Dasmariñas, Cavite: Lucena City; Pateros City

Intensity III – Makati City; Pasay City; Quezon City; Muntinlupa City; Malabon City; Mandaluyong City; Bacoor, Cavite

Intensity II – Daet, Camarines Norte

Phivolcs Director Renato Solidum told Rappler in a phone interview that there is nothing unusual about earthquakes occurring just a minute apart in the same area.

Solidum added that the twin tremors are related to the magnitude 5.5 earthquake that hit Batangas last Tuesday, April 4. There were no casualties during the Tuesday quake but structures, including the Batangas Provincial Capitol building, were damaged.

Aftershocks have also begun following Saturday's twin tremors, including a magnitude 4.1 quake that hit 3:29 pm and a magnitude 4.7 quake at 4:36 pm.

Stronger tremors

In an interview with dzMM, Batangas Governor Hermilando Mandanas said more people in the province feared Saturday's quakes as these were stronger than the one they experienced last Tuesday.

He added that Batangas City has no power supply. (READ: Batangas residents flee for safety after twin quakes)

"Mas malakas talaga. At ngayon, walang kuryente sa Batangas City. Noon hindi. Mas marami ngayon ang medyo kinakabahan pa," Mandanas said.

(It's really stronger. And now, there's no electricity in Batangas City. This didn't happen the last time. More people are scared now.)

Mandanas said based on initial reports, there were no reported injuries in his province as of early Saturday afternoon. (LOOK: IN PHOTOS: #QuakePH causes panic, damage in Batangas resort)

Meanwhile, the quakes prompted a few schools to suspend classes for Saturday.

Don't share unverified info

Malacañang urged the public to "stay calm and yet remain vigilant and alert" following the quakes.

"Let us not forward information from unverified sources that may cause undue alarm. Disaster officials are assessing the situation and will be giving updates to the public as more information… becomes available," Presidential Spokesperson Ernesto Abella said in a statement on Saturday.

Solidum also corrected wrong reports circulating online that have caused panic in areas hit by the strong quakes on Saturday. (READ: Batangas residents flee to safety after twin quakes)

Meanwhile, the Department of Social Welfare and Development (DSWD) said in a statement that it is in close coordination with its field offices and concerned local governments for "possible augmentation support and assistance" following the quakes.

"Currently, the Department is now under blue alert status. However, there is already a recommendation to elevate the alert status to red because of the gravity of the impact of the earthquake in several [structures] and facilities, including hospitals such as the Batangas Medical Center and Taal Hospital," the DSWD said.

It added that it sent on Saturday 50 tents from the DSWD National Resource Operations Center (NROC) for distribution to the families who conducted preemptive evacuation, and bottles of water and blankets. – Rappler.com</s>Two earthquakes rattled Batangas Saturday afternoon - the second registering at magnitude 6.0 - in the same area struck last April 4 by a quake that caused residents to flee their homes. The first magnitude 5.6 earthquake struck at 3:07 p.m. and was followed by a strong magnitude 6.0 quake at 3:09 p.m., with the epicenter in Mabini, Batangas.

Start the conversation, or Read more at Sun-Star.</s>(Updated, 4:09 p.m.) Subsequent earthquakes were felt in parts of Luzon on Saturday afternoon.

A 5.7-magnitude earthquake east northeast of Mabini, Batangas was felt in neighboring provinces and as far as Metro Manila shortly after 3 p.m. It was followed closely by a 5.9-magnitude quake south southwest of Tanauan, Batangas, and then by a 5.0-magnitude quake west northwest of Taysan, Batangas, the United States Geological Services (USGS) said.

The Philippine Institute of Volcanology and Seismology (Phivolcs) pegged the Mabini, Batangas at magnitude 5.6 with a depth of 4 kilometers.

Inquirer staff reported they felt a shaking of the ground in Sta. Mesa, Manila, Sto. Tomas, Batangas, Subic Bay, Zambales, Makati City and Mandaluyong City.</s>Three strong earthquakes jolted Batangas, its neighboring provinces in Calabarzon (Cavite, Laguna, Batangas, Rizal and Quezon), Camarines Sur, Romblon and Mindoro, and as far as Metro Manila, prompting massive evacuation in offices and malls across the National Capital Region (NCR) and Calabarzon.

The first tremor, at 5.7-magnitude earthquake east northeast of Mabini, Batangas was felt up to as far as Metro Manila shortly after 3 p.m.

It was followed closely by a 5.9-magnitude quake south southwest of Tanauan, Batangas, and then by a 5.0-magnitude quake west northwest of Taysan, Batangas, the United States Geological Services (USGS) said.

The Philippine Institute of Volcanology and Seismology (Phivolcs) pegged the Mabini, Batangas at magnitude 5.6 with a depth of four kilometers. Aftershocks were expected, Phivolcs said.

It also recorded quake intensities in following areas: Intensity 7 – Mabini, Batangas; Intensity 6 – Calatagan, Nasugbu and Tingloy, Batangas; Intensity 5 – Batangas City, Sto. Tomas and Lemery in Batangas; Tagaytay City in Cavite; Intensity 4 – Dasmariñas, Cavite: Lucena City in Quezon Province and Pateros City; Intensity 3 – Makati City, Pasay City, Quezon City, Muntinlupa City, Malabon City, Mandaluyong City, and Bacoor, Cavite; and Intensity 2 – Daet, Camarines Sur.

Magnitude refers to the energy released by the earthquake, while intensity refers to a tremor’s strength.

 Inquirer staff reported they felt a shaking of the ground in Sta. Mesa, Manila, Sto. Tomas, Batangas, Subic Bay, Zambales, Makati City and Mandaluyong City.

Major establishments and mall complexes, including the SM Southmall in Las Piñas City, ordered an evacuation due to strong aftershocks.

 The Quezon City Disaster Risk Reduction Management Office has also directed City Hall security to evacuate all City Hall buildings as a precautionary measure following the earthquake.

QC DRRMO chief Karl Michael Marasigan said all employees rendering overtime work at QC Hall will not be allowed to reenter the buildings until after an all-clear signal is given by the City Engineering Department on the structural integrity of the buildings.

 The directive was also made in anticipation of possible aftershocks.

City Hall staff on duty at the QC DRRMO Emergency Operations Center along Kalayaan Avenue may however continue working as the building is rated to withstand a powerful earthquake.</s>A 5.5-magnitude earthquake struck Batangas last Tuesday, sending portions of the walls of the Taal Basilica crashing down, followed by 60 aftershocks that were felt all over Southern Luzon and Mindoro as well as Metro Manila and Bulacan. Before Batangas, there was Surigao in February, then Caraga, Davao, Socksargen, and Surigao again.

Start the conversation, or Read more at Manila Bulletin.</s>A series of tremors that hit Batangas on Saturday afternoon, with magnitudes between 5 to 6, were apparently part of an “earthquake swarm,” which had been going on since since Tuesday evening, according to the Philippine Institute of Volcanology and Seismology (Phivolcs).

The first tectonic earthquakes on Saturday hit only minutes apart, at 3:07 p.m. and at 3:09 p.m., and were felt as one long earthquake – lasting from 10 to 15 seconds – in affected areas.

Two other earthquakes originating from around the same epicenter was recorded at 3:53 p.m. and 3:59 p.m.

The first two of the land-based Saturday quakes, originating in the vicinity of Mabini town, were both stronger than the 5.5-magnitude temblor originating near the island of Tingloy, Batangas on Tuesday, with the first Mabini quake having a magnitude of 5.6, and the second reaching magnitude 6.

The third moderately-sized earthquake in Batangas on Saturday was of magnitude 5.1 and the fourth, magnitude 5.3.

Based on the Phivolcs earthquake bulletins by 5:00 p.m. on Saturday, the first earthquake’s epicenter was located 1 kilometer southwest of Mabini, Batangas, with a depth of focus of 27 kilometers. The second had an epicenter 12 kilometers northwest of Mabini, with a depth of 24 kilometers.

The consecutive earthquakes were felt at varying intensities in the following areas;
• Intensity V in Batangas City, Santo Tomas, Lemery in Batangas and in Tagaytay City, Cavite
• Intensity IV in Dasmarinas, Cavite; Lucena City in Quezon; and Pateros City in Metro Manila
• Intensity III in Makati, Pasay, Quezon, Muntinlupa, Malabon, and Mandaluyong in Metro Manila; and in Bacoor, Cavite

According to reports reaching Phivolcs, the effects of the quakes were felt even in Olongapo in Central Luzon.

“There is no danger of tsunami, but with Intensity VII, we expect damage,” Phivolcs supervising science research speciality Jeffrey Perez said, in an interview

Saturday’s quakes, he added, could worsen the damage wrought by the Tuesday temblor.

As of this writing, no reports of liquefaction or ground ruptures have come in.

Perez attributed the quakes with similar magnitudes to the movement of active local faults in Mabini, Batangas.

“We’re looking at this as a series of earthquakes since Tuesday,” Perez said.

He describe an earthquake swarm as a series of moderately-sized earthquakes in the same area over a certain period of time.

“It’s like there were big boulders that have moved, and until now are still moving, trying to return to a stable state,” Perez explained.

He said that, since the Tuesday evening temblor, 991 aftershocks had already been recorded as of 3:00 p.m on Saturday, with 21 being felt.

These, too, were part of the earthquake swarm, he said.

The Phivolcs expected further aftershocks, but it could not say definitely whether the next quakes would be stronger or weaker.

Though the Mabini fault was far from and had no effect on Metro Manila’s faultlines.

“It’s a warning that we really need to prepare, if we’re affected even by faults that are far from us,” Perez said. “The whole country has a lot of local faults that generate moderate to strong earthquakes. Each province has their own ‘Big One’.” /atm</s>Some schools declared suspension of classes after subsequent earthquakes were recorded in Batangas and felt in neighboring provinces and Metro Manila on Saturday afternoon.

Effective 3:30 p.m., De La Salle University suspended its classes in all levels as well as office work at the Taft, Makati, and BGC campuses. Access to these campuses is constrained until further notice.

The University of Santo Tomas also suspended classes as of 3:50 p.m.

Far Eastern University followed, suspending classes in its Manila and Makati campuses and FEU Tech. IDL</s>MANILA, Philippines — Back-to-back earthquakes cracked small buildings and blocked roads with minor landslides Saturday in a Philippine resort province south of Manila where jittery tourists left and patients were evacuated from a hospital during aftershocks.

Officials said an earthquake with a magnitude of 5.6 struck near Mabini town in Batangas province at midafternoon, followed shortly by a magnitude 6 quake, prompting many people to rush out of homes and beach resorts. The quakes were felt in outlying regions, including in Manila, the capital, where people rushed out of some buildings and hotels in a panic as the ground shook and chandeliers swayed.

“Our tourists left out of fear they may be affected by the earthquakes,” Mayor Noel Luistro of Mabini, which is popular for diving and snorkeling, told DZMM radio network. “I need to declare a state of calamity.”</s>MABALACAT CITY --- Senator Loren Legarda has renewed her call for heightened earthquake preparedness following several temblors that hit the country, particularly in Southern Luzon in the past few days.

At least two earthquakes with magnitude 5.6 and 6.0 jolted Batangas and were felt in nearby areas including Metro Manila on Saturday, only four days after a 5.5 earthquake also hit the province.

These tremors have caused damages to structures.

“We never know when an earthquake will occur. But we should know what to do before, during and after the occurrence of such events. Regular safety drills should be done to familiarize citizens with safety and disaster preparedness measures,” said Legarda, UNISDR Global Champion for Resilience.

She also reminded that disaster management agencies, local government units (LGUs), community leaders, and even citizens should prepare for the Big One, or the projected 7.2-magnitude earthquake in Metro Manila.

“The key to effective disaster prevention is planning. It is important to know if our location is near an active fault and prone to liquefaction or landslide, which may cause damage to houses or buildings. We have to ensure that buildings are not standing on active faults. Evaluation and retrofitting of public and private infrastructure is crucial in ensuring that buildings, bridges and other similar structures can withstand strong quakes,” she stressed.

Legarda explained that earthquakes turn into major disasters due to unsafe structures—poorly built structures, buildings in inappropriate places, inadequate design and materials specification, and shortcuts in construction.

“The additional expense required for making structures safe from earthquakes is worth it especially if it would save thousands of lives,” she said.

“LGUs and barangay leaders must prepare their communities especially by determining open spaces for safe refuge when earthquakes occur and crafting evacuation plans that would help citizens find out the fastest and safest way to reach open spaces and other safe areas,” she added.

Legarda also emphasized the importance of an effective early warning system and massive information and education campaign to equip citizens with knowledge on what to do before, during and after such disasters.

She cited the “5:00 p.m. chime” or the “Municipal Disaster Management Radio Communication Network” of Minato City in Japan wherein every 5:00 in the afternoon the instrumental version of the Japanese folk song “Yuyaku Koyake” is heard in speakers all around the city.

The daily “5:00 p.m. chime” is a way to ensure that the broadcast system and speakers are working correctly because the speaker network is used to warn people of emergency situations, especially disaster warnings.

“We also need to have this kind of early warning system in the country, so that wherever people are they are informed of important announcements especially in emergency situations such as before, during and after disasters, thereby reducing risks, casualties and damages,” Legarda said.

Legarda reminded that ensuring the structural integrity of buildings and preparedness measures for earthquakes can significantly reduce the impacts projected in the 2004 Metro Manila Earthquake Impact Reduction Study (MMEIRS), which revealed that without the necessary interventions, a 7.2-magnitude earthquake in Metro Manila could destroy 40% of residential buildings, damage 35% of all public buildings, kill 34,000 people, injure 114,000 individuals, and the ensuing fires will also result in 18,000 additional fatalities.</s>Three strong earthquakes rocked a coastal region near the Philippine capital within half an hour of each other on Saturday, sending people running out of buildings.

There were no immediate reports of damage or casualties from the quakes, the strongest of which hit the coast close to the town of Mabini, in Batangas province south of Manila.

The first 5.7-magnitude temblor struck inland at 3:08 p.m. followed by the 5.9-magnitude quake just a minute later, their epicenters within a few kilometers of each other, according to US geologists.

The 5-magnitude quake hit in the same region after another 20 minutes.

The Philippine Institute of Volcanology and Seismology (Phivolcs) later reported different readings, but putting the strongest temblor at a magnitude of 6.

The quake was followed by three weaker quakes with magnitudes 3.5 to 4.7.

The quake was felt in varying intensities in surrounding areas and as far as Manila’s financial district of Makati, where local broadcaster ABS-CBN showing live footage of frightened commuters fleeing the passenger terminal at the port of Batangas, near the epicenters.

ABS-CBN quoted local officials as saying the quakes broke the windows of some houses in the region, but there were no reports of casualties.

The series of temblors was caused by tectonic in origin and caused by the movement of a local fault, said Renato Solidum, Phivolcs head.

“We can call this an earthquake swarm,” Solidum said in a television interview. Swarms are events where a local area is hit by a sequence of many quakes in a relative short period of time.

“Swarms” differ from earthquakes succeeded by a series of aftershocks because no single earthquake in the sequence is considered the main shock.

Solidum said the quakes were not powerful enough to cause tsunamis, although he welcomed news that many people immediately went to higher ground at the onset of the quake.

“This is tectonic in origin, caused by the movement of a local, unnamed fault between the towns of Tingloy and Mabini,” he said.

The movement was felt in varying intensities in about 40 towns in Batangas, Laguna, Cavite and Quezon and in metropolitan Manila. As of 4:43 p.m. nearly 800 small aftershocks were recorded, but they were too weak to trigger any tsunamis or damage.

Power was cut off but was immediately restored in affected areas, but centuries-old churches and some establishments in Batangas sustained minor damage, including the fire station in the city, disaster relief officials said.

At least 8,000 people, including patients in four hospitals in the province, were evacuated to open areas as the swarm shook buildings in Batangas.
Two earthquakes, with magnitudes of 5.6 and 6.0 and related to the April 4 magnitude 5.5 earthquake, hits Batangas, and are felt as far as Metro Manila (Rappler)