Multiple Earthquakes Hit Oregon Coast Including A 5.7 Magnitude

The Oregon Coast was hit with multiple earthquakes over a short time frame Tuesday evening.  The majority of the quakes were roughly 100 miles off the shoreline according to The United Stated Geological Service, and recorded between roughly 8:29 and 8:50pm.

They seven quakes ranged from the smallest magnitude of 3.5 to the largest of 5.7.  All of the quakes hit west south west of Port Orford, OR.  The two closest were registered 167 kilometers (roughly 103 miles) off the coast and were a 3.9 and 4.8 magnitude respectively.

All of the quakes occurred under the Pacific Ocean at an approximate depth of 6.2 miles.  The USGS catalogued Nineteen reports from people feeling the quakes, Seventeen of those reported were in conjunction with the 5.7 magnitude.  No injuries or damage was reported.

Was There a Danger of a Tsunami?

A 5.7 magnitude, the strongest of the bunch, is considered a 'moderate' size quake.  Earthquakes in the Pacific Ocean are also more common than you think.  In order for an earthquake to rigger a tsunami, according to the National Oceanic and Atmospheric Administration (NOAA), a few factors need to be present.

1. Tsunami-generating earthquakes occur mostly in subduction zones.
2. If big enough ,and close enough to the ocean floor, a quake's energy can create a rising and falling of the ocean floor.  That generates the tsunami.
3. Most tsunamis result from earthquakes with magnitudes over 7.0 that occur under or close to the ocean and less than 62 miles below Earth's surface

The biggest of the quakes that hit off the Oregon Coast was below seven, so the the force wasn't there to generate a tsunami.  The majority of tsunamis in the Global Historical Tsunami Database resulted from large earthquakes and/or landslides caused by earthquakes.