Latest Cascadia subduction zone Stories

Link to earthquakes unclear, but tremors seem to increase stress on shallower fracture zoneThe faint tug of the sun and moon on the San Andreas Fault stimulates tremors deep underground, suggesting that the rock 15 miles below is lubricated with highly pressurized water that allows the rock to slip with little effort, according to a new study by University of California, Berkeley, seismologists."Tremors seem to be extremely sensitive to minute stress changes," said Roland...

For most of a decade, scientists have documented unfelt and slow-moving seismic events, called episodic tremor and slip, showing up in regular cycles under the Olympic Peninsula of Washington state and Vancouver Island in British Columbia. They last three weeks on average and release as much energy as a magnitude 6.5 earthquake.Now scientists have discovered more small events, lasting one to 70 hours, which occur in somewhat regular patterns during the 15-month intervals between episodic...

Another way to save lives in the Pacific NorthwestSome time soon, a powerful earthquake will trigger a massive tsunami that will flood the Pacific Northwest, destroying homes and threatening the lives of tens of thousands of people, says Yumei Wang, a geotechnical engineer at the Oregon Department of Geology and Mineral Industries in Portland.The region's geology makes an earthquake-triggered tsunami inevitable and imminent in geologic time, Wang says, yet coastal towns and cities in the...

A spike in mysterious underground rumblings observed on a section of the San Andreas fault near Parkfield, California, could indicate a build-up of stress and an increased likelihood of a major earthquake, said scientists at the University of California, Berkeley.The researchers monitored seismic activity along a heavily instrumented segment of the central San Andreas Fault from July 2001 to February 2009, and recorded more than 2,000 tremors lasting from minutes to nearly half an...

A new study evaluates expected ground motion in Seattle, Victoria and Vancouver from earthquakes of magnitude 7.5 - 9.0, providing engineers and policymakers with a new tool to build or retrofit structures to withstand seismic waves from large "subduction" earthquakes off the continent's west coast.The Cascadia subduction zone in the Pacific Northwest has produced great earthquakes of magnitude 9.0 and larger, most recently in the 1700s. Now home to millions of people and a vast...

Seattle's tallest buildings are at risk of collapse during a rupture of the Cascadia fault zone in the Pacific Northwest, say U.S. seismic experts.The Cascadia subduction zone is likely to produce the strongest shaking experienced from earthquakes in the lower 48 states, said seismic experts from the California Institute of Technology in Pasadena.While the Pacific Northwest has experienced little seismic activity in 200 years, there is growing consensus the Cascadia subduction zone ruptures...

Researchers are using modern technology to study "silent earthquakes" along a major fault zone beneath the Nicoya Peninsula in Costa Rica. Also known as slow slip events, they involve the same motion as an earthquake, but they occur so slowly that they can only be detected by networks of modern instruments.Scientists are using a network of 13 Global Positioning System (GPS) monitoring stations and 13 seismic stations to measure precisely the movements of the Earth's crust on the...

In the last decade, scientists have recorded regular episodes of tectonic plates slowly, quietly slipping past each other in western Washington and British Columbia over periods of two weeks or more, releasing as much energy as a magnitude 6 earthquake.The slip events coincide with regular occurrences of what scientists call nonvolcanic tremor, which showed up clearly on seismometers but for which the origins were uncertain.Now researchers from Italy and the University of Washington have...

Scientists released the first official statewide forecast of earthquake probabilities for California Monday, reporting a 99 percent probability of a strong and damaging earthquake of magnitude of 6.7 or greater occurring along one of the state's major seismic faults within the next 30 years.The report, submitted by federal and state seismologists, geologists and geophysicists, said there was a 46 percent chance of an even more damaging magnitude 7.5 or greater earthquake occurring during the...

A peculiar swarm of earthquakes have been occurring off of Oregon's central coast, resembling those that happen just prior to a volcanic eruption. However, scientists are baffled as there are no volcanoes in the area.  There have been more than 600 quakes during the past 10 days in an area 150 miles southwest of Newport. The largest quake was a magnitude of 5.4, with two others measuring greater than magnitude 5.0, OSU reported.Few of the quakes have been strong enough to be felt on land,...