Strong and shallow M6.1 earthquake hits Luzon, Philippines – at least 16 people killed

A strong and shallow earthquake registered by the USGS as M6.1 hit Luzon, Philippines at 09:11 UTC on April 22, 2019. The agency is reporting a depth of 40.2 km (24.9 miles). EMSC is reporting the same magnitude and depth. This earthquake can have a medium humanitarian impact based on the magnitude and the affected population and their vulnerability.

PHIVOLCS is reporting M6.1 at a depth of 10 km (6.2 miles). Small-magnitude earthquakes followed afterwards, and as of 08:00 LT on April 23, 421 aftershocks have been recorded by the PHIVOLCS-DOST seismic monitoring network.

The epicenter was located 1.4 km (0.9 miles) NNE of Gutad (population 2 623), 8.1 km (5 miles) NNE of Dinalupihan (population 66 670), 8.4 km (5.2 miles) WNW of Santa Cruz (population 15 408), 11.6 km (7.2 miles) W of Lubao (population 55 645) and 23.1 km (14.3 miles) WSW of San Fernando (population 251 248), Luzon, Philippines.

There are 31 530 000 people living within 100 km (62 miles).

4 273 000 people are estimated to have felt strong shaking, 15 871 000 moderate, 24 250 000 light and 91 000 weak.

At least 12 people have died in the town of Porac, NW of Manila, after a wall of a supermarket collapsed. At least 14 remain missing.

Pampanga Governor Lilia Pineda said almost all concrete electric posts in Lubao have fallen down, knocking out electricity in the province.

Large cracks were reported on the roads across the province.

The quake injured 81 people and damaged 29 buildings across Luzon.

Based on preliminary intensity reports, the strongest ground shaking was felt at PHIVOLCS Earthquake Intensity Scale (PEIS) VI (Very Strong) in San Marcelino and Subic in Zambales; Olongapo City; Floridablanca, Lubao, Porac, and Angeles City in Pampanga.

Intensity V (Strong) was felt in Tarlac City; Castillejos and San Felipe in Zambales; Magalang, Mexico, and San Fernando in Pampanga; Abucay, Balanga, and Mariveles in Bataan; Malolos, and Obando in Bulacan; Indang in Cavite; Lipa City in Batangas; Makati City, Mandaluyong City, Manila City, Quezon City, Pasay City, San Juan City, Taguig City and Valenzuela City.

Intensity IV (Moderately Strong) was felt in Meycauayan, Plaridel, and San Jose Del Monte City in Bulacan; San Rafael in Tarlac; Rosales and Villasis in Pangasinan; Itogon and La Trinidad in Benguet; Kasibu in Nueva Vizcaya; Gabaldon in Nueva Ecija; San Mateo and Antipolo City in Rizal; Bacoor, Imus, and Maragondon in Cavite; Nasugbu in Batangas; Baguio City, Tagaytay City, Caloocan City, Las Piñas City, Marikina City and Pasig City.

Furthermore, Intensity III (Weak) was felt in Marilao in Bulacan; Santo Domingo, Gapan City, Cabanatuan City, Palayan City, and Talavera in Nueva Ecija; Maddela in Quirino; Dingalan in Aurora; Lucban in Quezon; Carmona, Dasmariñas, General Trias and Silang in Cavite; San Nicolas and Talisay in Batangas; Calamba City and Santa Cruz in Laguna; and Muntinlupa City.

Intensity II (Slightly Felt) was felt in Baler, Aurora.

The strong ground shaking near the epicentral area resulted to damages to some buildings, roads, and bridges.

The USGS issued a green alert for shaking-related fatalities and economic losses. 

Overall, the population in this region resides in structures that are a mix of vulnerable and earthquake resistant construction. The predominant vulnerable building types are unknown/miscellaneous types and heavy wood frame construction.

Recent earthquakes in this area have caused secondary hazards such as landslides and liquefaction that might have contributed to losses.

Estimated population exposure to earthquake shaking

Selected cities exposed

Regional seismicity

Featured image credit: Google, TW/SAM