According to the USGS, a cluster of earthquakes was registered early Wednesday off the Oregon coast around 300 miles west of Newport but caused no damage. Geographical Survey
Within five hours, the agency reported nine earthquakes, three of which were barely minutes apart. At 2:54 a.m., the first earthquake was felt. The magnitude was 3.8. Eight more had struck by 7:01 a.m.
Small earthquakes in Oregon
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At 4:56 a.m., the series' greatest earthquake struck. The magnitude was 5.6, according to statistics.
There were no tsunami warnings, according to Joan Gomberg, a U.S. government official. Seismologist at the Geological Survey in Seattle.
It's nothing to be concerned about, and these are minor in comparison to their distance offshore," Gomberg added.
The seafloor must move up or down to cause a tsunami, and in this situation, the bottom is moving sideways.
The earthquakes occurred in the Blanco Fracture Zone, a fault between two tectonic plates that runs roughly 300 miles northwest of the Oregon coast and is known for producing numerous small earthquakes, according to Gomberg.
The Blanco Fracture Zone, according to Gomberg, should not be confused with the Cascadia Subduction Zone, a 600-mile fault that spans from northern California to British Columbia on the West Coast and is capable of delivering potentially disastrous earthquakes of magnitude 9.0.
The Blanco Fracture Zone is 200 miles closer to the Oregon coast than the Cascadia Subduction Zone.
The movement of the plates in subduction zones, where two tectonic plates meet, thrusting one plate beneath the other, may build mountains and volcanoes, as well as significant earthquakes and tsunamis.
In fracture zones, however, tectonic plates move side to side and parallel to one other, resulting in significantly smaller earthquakes on average, according to Gomberg.
Earthquake technology that automatically stops or slows trains
In the case of an earthquake, Metrolink's Earthquake Early Warning System (EEW) is improving with new technology that automatically applies the brakes for safe and speedy slowing or stopping of trains.
A prior version of the system, which Metrolink began using in September 2021, could send automatic instructions to train personnel instructing them to begin slowing or stopping the train, but it did not have automated brake enforcement.
The second phase of this technology deployment is being tested between Riverside and Perris on Metrolink's 91/Perris Valley Line, which is sponsored by cooperation with the California Department of Transportation (Caltrans) and the United States Department of Transportation (USDOT) Survey of Geology (USGS).
The EEW is built on a connection between ShakeAlert, which is run by the USGS, and Metrolink's Positive Train Control (PTC) system.
ShakeAlert is an EEW system that gives critical information about an earthquake within seconds of its detection, such as the earthquake's origin, timing, position, and magnitude, so people and systems may be warned before shaking occurs.
PTC is intended to prevent train-to-train collisions, over-speed derailments, and other potentially dangerous situations.
According to Metrolink CEO Darren Kettle, the combination of ShakeAlert and PTC is a genuine game-changer.
This newest development reflects Metrolink's continued leadership in system safety and marks a significant milestone in our dedication to safeguarding our passengers, employees, and infrastructure.
The new system will also give improved data to help train network inspection and service restart following an earthquake.
