Pacific Spirit Marine Institute

Swarms of Earthquakes Off Oregon Coast. More than 600 quakes in 10 days. What’s going on?

Monday, April 14, 2008

Scientists using the Navy’s SOSUS, SOund SUrveillance System, hydrophones have been continuously listening to underwater sounds since 1991. That’s when the Navy program designed for Anti-Submarine Warfare was declassified. Since the early 1950’s, acoustic sensors installed across the ocean bottom at key locations have been doing sentry duty.

Since the end of the cold war and the advent of quieter submarines, designed to evade the pointed ears of the SOSUS, the hydrophones have been listening in on the underwater sounds such as volcanic eruptions, landslides, marine mammal and fish vocalizations, even weather. This swarm of latest earthquakes is another thing scientists are able to hear using this technology.

Click on this link to listen to earthquake sounds recorded by the SOSUS hydrophones. At this link you will also be able to hear the undersea sounds of volcanoes, both large and small ships, several types of Whales and explosives.

In the nearly 2 decades they have been listening scientists haven’t heard anything quite like what they are hearing recently. The 5.9 earthquake that may have kick off this latest swarm could be the one that happened on March 15Th. This quake, like the latest swarm happening over the past 10 days was also relatively shallow happening about 6 miles down.

Photo Thanks noaa.gov spectrogram of earthquake

Labels: NOAA, Oregon Earthquake, SOSUS, undersea sounds