April is Earthquake Preparedness Month. Oregon State University scientists estimate a 40 percent chance of an 8.0 or larger earthquake in the Coos Bay, Oregon area during the next 50 years. Do you have an emergency kit? Visit the Red Cross website below for a list of items to include in one. Prepare at least one week of food, water, and medications in your disaster kit. And don't forget favorite toys and books for the kids!Red Cross Emergency Kit List
Beneath our feet, the Earth's crust is broken into large, slowly moving pieces called plates. The Cascadia Subduction Zone stretches from Vancouver Island, BC to northern California. In this zone the oceanic Juan de Fuca Plate is sinking (subducting) under the continental North American Plate. This movement shapes the spectacular geology of the Pacific Northwest, creating the Coast Range Mountains and Cascade Volcanoes. It's also why we're primed for an earthquake on the scale of the magnitude 9.0 Japanese earthquake and tsunami that hit in 2011. As the plates slide against each other, they stick. Whent the stress becomes too great, the Cascadia fault will rupture and the ground will suddenly move, resulting in an earthquake.
Scientists from Oregon State University have been studying turbidites, layers of mud and sand deposited in undersea canyons from tsunamis, earthquakes, storms, or slope failures. In the geologic record of the past 10,000 years they have identified 19 earthquakes of magnitude 8.7 - 9.2 in Oregon and Washington. These were faults that ruptured along the Cascadia Subduction Zone. They also identified another 22 earthquakes of magnitude 8.0 or larger along the southern part of the zone near the California border, an everage of one every 240 years. The last earthquake on that scale was on January 26, 1700; a magnitude 8.7 - 9.2 quake that shook both Oregon and Washington and sent a tsunami to Japan.
What can we do to get ready for the next large earthquake? If you visit or live on the coast, know the warning signs of a tsunami and identify evacuation routes. We can all advocate for retrofitting our public buildings and bridges, earthquake ready our own homes, have a personal emergency plan and kit, and get to know our neighbors. Emergency responders will be overwhelmed with calls at first so we'll need to rely on the people nearby for support.
For more information check out:Living on Shaky Ground: How to Survive Earthquakes and Tsunamis in Oregon
, a great booklet on why we get earthquakes and tsunamis in the Pacific Northwest and how to prepare for them.Portland Bureau of Emergency ManagementThe Orphan Tsunami of 1700 by Brian AtwaterOregon State University Turbidite Research