Prediction of Long-Period Ground Motion during the 2019 Central Luzon Earthquake in the Philippines

Simulations of the fault rupture within the fault system were calculated using the parameters of the 2019 M6.1 Zambales earthquake and were compared to actual strong motion data. A fault model of the East Zambales Fault, which traverses the eastern side of the Zambales Range, was used in the simulation. By using the results of microtremor array measurements at different locations, we limit the structure velocity model applied in our calculations. In order to compare the results of actual strong motion data to the simulations, the coordinates of nine strong motion stations around the vicinity were selected and were used as coordinates for the peak ground motions of the simulations. The methodology used assesses the long-period ground motion that originates from a finite fault source model consisting of multiple asperities embedded in a velocity structure. The comparison of the actual strong motion data to the simulated earthquake scenario of the M6.1 earthquake in Zambales shows that the arrival time and peak of their velocity and acceleration response spectra are comparable. The results can be used as input data to evaluate the effects of deep underground soil layers and to calculate the soil response at different sites in Zambales during earthquakes.