1658 and 1880 earthquakes in 'Metro Manila', Marikina Valley Fault System and Infanta Segment of PFZ as source faults

Bell Tower of the Manila Cathedral collapsed from the 1880 tremor. 

The destructive 1880 Luzon Earthquake, one of the most destructive in the country's history that jolted Manila, Cavite, Bulacan, Laguna, Pampanga and Nueva Ecija and destroyed many old churches and converted buildings into shapeless heaps of ruins was not caused by the West Valley Fault or East Valley Fault. According to a study (Bautista 2000), the source fault for the 1880 event was the Infanta Segment of the Philippine Fault Zone.

In the same study it was supposed that the source fault of the 1658 and 1771 events were the East Valley Fault and not the West Valley Fault (of the Marikina Valley Fault System), and that "no event along the WVF is known".

However, Renato Solidum, director of the Philippine Institute of Volcanology and Seismology (Phivolcs) has said it has been 357 years since the 90-kilometer fault system shifted, reiterating the agency's warning issued back in 2013.

"Ang kada galaw ng [West Valley Fault] ay 400 to 600 years at ang last niyang gumalaw ay 1658—357 years ago," he said. "So 357 and 400, magkalapit 'yan kasi either gumalaw 'yung fault nang mas maaga or mas later."

Jerry Velasquez, United Nations International Strategy for Disaster Reduction regional coordinator, explained in a Facebook post that the magnitude 7.2 earthquake is "not a prediction over a specified time."

"Rather it is the estimated largest credible earthquake that can be generated by movement of the Valley Fault System--which runs right through Metro Manila--based on available geological and seismological data," Velasquez explained.

 Marikina Valley Fault System

The Marikina Valley Fault System (also known as Valley Fault System, West Valley Fault/ East Valley Fault, Marikina Fault Line) is a group of dextral strike-slip fault which extends from San Mateo, Rizal to Taguig City on the south; running through the cities of Makati, Marikina, Paranaque, Pasig and Taguig which are part of what is now known as Metro Manila.

The East Valley Fault, on the other hand, is about 10 kilometers long and traverses the municipalities of Rodriguez and San Mateo in Rizal. East Valley Fault is said to move in an “oblique dextral” motion and can generate a magnitude 6.2 earthquake.

Has there been some kind of mix-up by the experts? It's not to douse cold water on the important earthquake drills carried out today in Metro Manila which are important in a country that sits on the Pacific Ring of Fire, but the following from Earthquake Impact Reduction Study for Metropolitan Manila, with materials sourced from Phivolcs, is rather interesting reading:

Some of the most damaging earthquakes to Metropolitan Manila are those that occurred in 1658, 1771, 1863, 1880 and 1937. As for the source fault of these earthquakes it has been supposed (Bautista 2000), that East Valley Fault (EVF) is the source of the 1658 and 1771 event, Infanta Segment of PFZ as the source fault of the 1880 event and Laguna-Banahaw Fault that runs north to south along the east coast of Laguna Lake as the source fault of the 1937 event. Only the 1677 event and the 1863 event have the description of tsunami around Metropolitan Manila.

Bautista (2000) has suggested that the 1658 and 1771 earthquakes are candidate events for the EVF. However, no event along the WVF is known. If no earthquake had occurred at the WVF after the 16th century, then the earthquake occurrence along the WVF becomes a serious threat.

The destructive earthquake of 1880 in Luzon. (Source Fault is the Infanta Segment of PFZ)

Source: Wikipedia - The earthquakes of July 1880 in Luzon, the largest island of the Philippines, was one of the most destructive tremors on record in the history of the country. The shocks continued, with greater or less interruption, from the 14th to the 25th of the month, highlighted by three violent shaking events, which destroyed churches and other buildings, producing loss of life. Coinciding with the tectonic activity was an increase in volcanic activity in Taal Volcano in southwestern Luzon.

The Luzon provinces of Manila, Cavite, Bulacan, Laguna, Pampanga and Nueva Ecija, were the chief victims from the terrible convulsions with Manila and Laguna receiving the most damages. In many places, buildings were converted into shapeless heaps of ruins, and the materials of their prosperity buried beneath the rubbish.

Church of Sinelesan (Laguna)

The view during the earthquake from the vessels in Pasig River, was, as described by an eyewitness, something to be seen to be appreciated. The rocking to and fro of the buildings was something terrific, the vessels moving about and bumping each other as though in a heavy seaway; the water of the river, bubbling up and mixed with the black mud of the river, was all the colour of ink; hundreds of people rushed off to the ships and remained all night. In Manila Bay, the same bubbling appearance was observable on the water, and the shock was distinctly felt on board the ships; the water's depth close in shore had been shallowed by some four feet in some places.

Church of  Malasiqui (Pangasinan)

Church of Mauban (Quezon, formerly Tayabas)

Church of San Agustin (Manila). Numerous vertical cracks in walls.

Church of San Jacinto (Pangasinan)

On the occasion of the earthquake, the people in Cavite across the bay saw Manila enveloped in a dense cloud of dust, and thought that Manila was completely destroyed. A very interesting phenomenon was also observed in Cavite. During the intensity of the earthquake, in the anchorage of Cavite, columns of black mud were seen to burst up, with a strong smell of sulphur. The very interesting phenomenon was also observed in Manila a few days previous to the destructive earthquake of 1863, in front of the Colgante suspension bridge on Pasig River. A column of blackish water was seen to burst up, which attracted the attention of the people.

Church of Binangonan (Infanta)

The day after, July 19 in the afternoon, Taal Volcano started issuing large mass of smoke, according to a telegraphic news from Taal, Batangas.

Distribution of faults and trenches around Metro Manila.