The 2022 Chihshang, Taiwan, Earthquake: Initial GEER Team Observations
We recently returned from a post-earthquake reconnaissance trip to Taiwan sponsored by the National Science Foundation–funded Geoengineering Extreme Events Reconnaissance (GEER) Association. We studied the effects of the September 18, 2022 MW6.9 Chihshang, Taiwan earthquake. The earthquake occurred on the Central Range strike-slip fault, with the rupture direction extending north from the epicenter. Nearfield seismic stations measured peak ground accelerations (PGAs) exceeding 0.5g along the fault. Peak ground velocities (PGVs) increased in the direction of the rupture with average intensities of 8 cm/s near the epicenter, increasing along the fault to 89 cm/s at the northern terminus. The ground motion recordings of the east (approximately fault parallel) component indicated strong velocity pulses in the direction of the rupture (Fig. 1).