The fault line off the coast of Oregon has experienced multiple earthquakes in less than 12 hours, sparking fears that a major seismic event could soon strike.
The US Geological Survey (USGS) detected the latest tremor, a 5.1 magnitude, at 1:00pm local time on Tuesday, bringing the total to nearly a dozen above 2.5 magnitude.
The seismic activity began late Monday when a 5.8 magnitude tremor hit, triggering aftershocks throughout Tuesday.
The epicenter is about 102 miles west-southwest of Port Orford, Oregon, which also sits along the Cascadia Subduction Zone, where the Juan de Fuca Plate pushes beneath the North American Plate.
This fault system produces frequent small offshore tremors and carries the risk of massive, destructive earthquakes.
Scientists have long warned that the zone is overdue for a catastrophic event, with many nicknaming it the 'Sleeping Giant.'
The fault is capable of a magnitude 9 earthquake that would impact most of the northwestern US Coast, including Seattle and Portland.
Northern California has also experienced increased seismic activity on Tuesday, with the USGS detecting about half a dozen tremors above 2.5 magnitude.
In April, researchers at Virginia Tech found that an 8.0 magnitude or higher quake along the Cascadia Subduction Zone, combined with rising sea levels, would cause coastal land to sink up to 6.5 feet within 30 minutes of a major tremor.
They determined that an earthquake of magnitude 8.0 or higher, combined with rising sea levels, could cause coastal land to sink up to 6.5 feet within 30 minutes.
The most severe effects would hit southern Washington, northern Oregon and northern California, some of the region’s most densely populated areas.
This event would result in a significant expansion of the coastal floodplain, an area with a one percent chance of flooding each year, increasing it from 35 square miles to 116.
Such an event would expand the coastal floodplain from 35 to 116 square miles, placing an additional 14,350 residents, 22,500 structures, and 777 miles of roadway at risk.
Against this backdrop, Oregon Gov. Tina Kotek on Monday announced new seismic safety rules, just hours before the 5.8 magnitude quake hit.
Kotek's order requires all new state-owned buildings larger than 10,000 square feet to meet the strictest earthquake standards, while older structures must be upgraded to current life-safety codes by 2060.
No comments:
Post a Comment