Earthquake Types

Shallow Earthquakes

Also known as "Crustal" quakes, these shallow quakes are caused by faults in the North American Continent and include the following components.

Less than 15 miles deep
1,000 each year in Puget Sound
Most are not felt
They are random and unpredictable
Usually Magnitude 1 to 5

Deep Earthquakes

Also known as "Intra Plate" quakes, these quakes occur between the subducting oceanic plate as it bends beneath the continental plate, and include the following components.

40 Miles deep
6.0 to 8.0 magnitude
Every 20 to 30 years (1872 Magnitude 7.4, 1909 Magnitude 6.0, 1939 Magnitude 6.2, 1949 Magnitude 7.1, 1965 Magnitude 6.5, 1999 Magnitude 5.9, and Feb 28, 2001 Magnitude 6.8)

Subduction Earthquakes

Subduction Earthquakes are huge quakes that result when the boundary between the oceanic and continental plates ruptures. In 1700, the most recent Cascadia Subduction Zone earthquake, sent a tsunami as far as Japan.

Occur every 100-1,000 years
8.0+ Magnitude
Washington is along a 700 mile coastal subduction plate

Current Emergency Information

Menu