Earthquake Swarm in the News

During the week of December 6, 2021, a sequence of earthquakes off the coast of Oregon caught the attention of the press and the public. This swarm of quakes exceeded 50 in number by midweek, including 16 earthquakes greater than magnitude 5. By the end of the week, the swarm, which actually began in November, was slowing down, although the activity continues.

The location of these events is the Blanco Fracture (or Fault) Zone, a frequent-flyer as far as earthquake swarms go, but seismologists don’t consider the earthquakes generated at this busy intersection of tectonic plates to pose a threat to communities on the coast or to herald a rupture of the neighboring (but separate) Cascadia subduction zone, which lies approximately 200 kilometers (124 miles) to the east. For one thing, the Blanco is a transform fault (the Juan de Fuca plate is scraping its way past the Pacific plate in the direction of the North American plate): earthquakes here aren’t likely to cause the kind of displacement of the seafloor that produces a large tsunami. For another, the plates are relatively pliant: they tend to break in small events, rather than building up to big, catastrophic breaks.

So this recent earthquake swarm isn’t a cause for worry, but it is a great opportunity to direct public attention to the greater earthquake risks closer to home and to encourage personal and community preparedness.

Disaster Response Lessons from the Pandemic

Earthquakes can happen at anytime, even in the midst of another emergency situation. For example, emergency managers were already engaged in COVID-19 pandemic response when the magnitude 5.7 Magna earthquake shook up residents of Utah on March 18, 2020, and when a magnitude 6.5 earthquake struck near Boise, Idaho, on March 31, 2020.

Compound disasters in the midst of the COVID-19 pandemic have been challenging, but also instructive. A recent webinar hosted by the National Academies of Sciences, Engineering, and Medicine explores the lessons learned from the pandemic and how they can be applied to improve disaster planning and response, especially in situations where multiple disasters coincide.

View the webinar recording and read the report.