In response to earthquakes in Taiwan and Mexico, EERI’s Virtual Earthquake Reconnaissance Team (VERT) activated to develop two preliminary earthquake reports, which are now available:
EERI Lugu, Taiwan September 18, 2022, Mw 6.9 Earthquake Preliminary Virtual Reconnaissance Report (PDF)
On September 18th, 2022, at 2:44 pm local time, a moment magnitude 6.9 earthquake struck 42.7 km north of Taitung City, Taiwan. The earthquake was preceded by a magnitude 6.5 earthquake in the same area 17 hours earlier. The earthquake caused geotechnical failures and damage to infrastructure, mainly bridges, railroads, and highways. Damage to buildings was observed, but was primarily concentrated on older non-ductile structures and non-structural component damage. At least one building collapsed and hundreds more had some damage. The earthquake resulted in at least one death and 171 earthquake related injuries. The earthquake highlighted the vulnerabilities of older non-ductile concrete buildings in seismic regions, concrete bridges, and non-structural building components during an earthquake. This event also highlighted the importance of an earthquake early warning system. This report, led by VERT Co-Chair Erica Fischer (M.EERI 2010) provides a summary of the characteristics of the event, the seismicity of the impacted region, and an overview of the main effects of the earthquake as collected from publicly available information.
Train derailment at Dongli station in Hualien (Photo: Taiwan Railways Administration)
On September 19th, 2022, a moment magnitude 7.6 earthquake struck the Pacific coast of Mexico in the state of Michoacán between the cities of Manzanillo and Zihuantanejo. This is the third major earthquake that has occurred in Mexico on September 19th in the last 40 years. The earthquake mechanism corresponds to a reverse faulting mechanism characteristic of earthquakes that occur on or near the plate boundary between the Cocos and North American Plates. USGS focal mechanism solutions indicate that rupture occurred on a shallowly dipping thrust fault. The rupture of this earthquake is located approximately between the rupture of the great Mw8.0 September 19, 1985 to the South and the rupture of the great Mw8.0 October 9, 1995 to the North. The earthquake produced a small tsunami with a maximum measured wave amplitude of 1.7m in the port of Manzanillo. The report is a joint publication of EERI and SMIS (Sociedad Mexicana de Ingeniería Sísmica) and was led by LFE Co-Chair Eduardo Miranda (M.EERI 1987).
Health center in Aquila, Michoacán, evacuated due to structural
damage (Photo: El Sol de Morelia)
Additional Resources
Additional reports on these earthquakes are available on the LFE event page for each earthquake:
- NCREE Reconnaissance Report on Seismic Damage Caused by Guanshan Earthquake and Chihshang Earthquake, Taiwan, 2022
- El sismo de Coalcomán, Michoacán, del 19 de septiembre de 2022 (M7.7) Informe Virtual Preliminar 26-09-2022
Acknowledgments
Special thanks to the more than 50 volunteers who contributed to the development of these reports! Members interested in joining VERT to contribute to future earthquake activations can join through the sign-up form here.
EERI’s Learning from Earthquakes program is supported by the generous contributions of donors to the LFE Endowment Fund.
