Why does the Pacific Northwest have earthquakes?
We are located at a convergent continental boundary, where two tectonic plates are colliding. This boundary is called the Cascadia Subduction Zone. It lies offshore and runs from British Columbia to northern California. The two plates are converging at a rate of about M 3-4 cm/year (1-2 inches/year), and the northeast-moving Juan de Fuca Plate is pushing into North America, causing stress to accumulate. Earthquakes are caused by the abrupt release of this slowly accumulated stress. • Q: How often do earthquakes occur in the Pacific Northwest? A: Typically, each year we locate over 1000 earthquakes with magnitude 1.0 or greater in Washington and Oregon. Of these, approximately two dozen are large enough to be felt. These felt events offer us a subtle reminder that the Pacific Northwest is an earthquake-prone region. As residents of the Pacific Northwest, we should be prepared for the consequences of larger earthquakes that could result in damage to the transportation systems and lifelin
