StEER has released an Event Briefing for the recent M6.2 earthquake in Northern California:

Mosalam, K. Gunay, S. Kijewski-Correa, T. Robertson, I. (2021) "Petrolia Earthquake Event Briefing", in StEER - 20 December 2021, Petrolia, Mw 6.2 Earthquake. DesignSafe-CI. https://doi.org/10.17603/ds2-4m8k-eh86.

Briefing highlights:

• There are a large number of ground motion recording stations in the vicinity of the epicenter of this earthquake including two instrumented bridges in the earthquake area, supporting ongoing study of this earthquake.

• A ground motion recording station in Ferndale, CA recorded a peak ground acceleration (PGA) of 28.7% g, which led to minor nonstructural damage. If these preliminary values are accurate, the observation of no structural damage indicates good seismic performance of structures in this region.

• California's Office of Emergency Services indicated that 2,500 people were notified about the earthquake in advance of strong shaking through the state's earthquake early warning system.

• This earthquake is another reminder of the potential of major earthquakes along the Pacific coast; coupled with the earlier flurry of earthquakes off the Oregon coast, attention should be given to this series of strike-slip earthquakes along the flanks of the Juan de Fuca plate.

Based on these findings, StEER will maintain this response at a Level 1 culminating in this product and will not activate a VAST or FAST unless further damage reports surface.