Large swaths of southern California, including Los Angeles, were hit by two sequential earthquakes last Thursday and Friday, July 4 and 5. Many on the West Coast, accustomed to warnings about “The Big One”, are feeling a mutual sense of unpreparedness.
A new earthquake warning system, delivered via smartphone app, is being developed by the U.S. Geological Survey. It was first deployed in LA, with plans to eventually cover the entire West Coast. However, the system failed to notify residents on Thursday because its effects in LA fell shy of the system’s threshold to send out a warning. City officials told reporters they are working to lower that threshold.
In Oregon, earthquakes are also a fairly normal occurrence, though mostly in the form of benign quakes off the coast like the half dozen recorded on June 22. The threat posed by a quake beneath a population center is an ongoing political battle as well, as the state attempts to fund the restoration or replacement of certain dilapidated structures, like bridges, which could potentially collapse during a strong enough seismic event.
The city of Portland is also considering a policy of mandatory seismic retrofits on the thousands of “unreinforced masonry buildings” (UMBs) in the city. According to Portland Bureau of Emergency Management Dan Douthit, a serious earthquake would mean Portland “could face a lot of damage and potentially loss of life and significant injuries from the [UMBs].” Business and property owners strongly dislike the idea, which would be expensive for them.
However, recent budget decisions in Salem may lead to the closure of Oregon’s Department of Geology and Mineral Industries, known as DOGAMI, an agency which studies geological hazards, including earthquakes. The agency has gone quite far over its budget and failed to meet inspection requirements over the past few cycles. But DOGAMI head Brad Avy claims this was due to the agency’s funding becoming increasingly uncertain and shifted onto reliance on grants.
California Institute of Technology seismologist Egill Hauksson told reporters that this “sequence” could lead to over 30,000 “aftershocks” at least 1.0 in magnitude. He estimated the chances of another 7.0+ quake to be around 3%, but expected to see one or two more 6.0+ events.
By Ian MacRonald