SEATTLE, WA - The massive earthquake that struck off the coast of Mexico Thursday night happened along a subduction zone, which is the same type of fault that threatens the Pacific Northwest. The magnitude 8.1 quake happened where the Cocos Plate dips under the North American Plate. At some point the Juan de Fuca plate off the Pacific Coast of Washington will unlock from the North American Plate, either in part of across the whole plate, and could cause a quake bigger than Chiapas.

A full rip of the Cascadia subduction zone - the zone extends from Vancouver Island to Northern California - would be a devastating event up and down the West Coast. A Cascadia event could cause up to a 9.0 magnitude quake with intense shaking lasting up to five minutes. The shaking would level un-reinforced buildings and roadways, sever utility lines and rupture gas and oil pipelines. About 20 minutes later, a tsunami would hit the West Coast and cause destruction similar to the March 2011 megaquake in Japan. Up to 13,000 people could die, according to emergency officials. The Chiapas quake was so powerful that it registered on local seismic monitors at Mt. Rainier and in Bremerton. (For more updates on this story and other news around Seattle, click here to subscribe to Patch's daily newsletter and free, real-time news alerts.)

There are two main types of earthquake faults, the other being strike-slip faults, which move horizontally. The San Andreas and Seattle faults are strike-slip faults and can cause powerful earthquakes, but not as powerful as a full-rip subduction zone events. Scientists can't predict earthquakes, so it's still murky whether a big quake in Mexico (or Japan or Chile) could trigger a Cascadia quake - but the U.S. Geological Survey always tells people to be prepared for a big one. Puget Sound residents should have a disaster kit ready, and establish a communications and meeting plan with family members.