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 movement at the trench was specifically the Philippine Sea plate subducting below the neighboring plate, releasing seismic energy. “
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 Mw event was the mainshock. == Damage ==