DEFINITION: "An earthquake is a term used to describe both sudden slip on a fault, and the resulting ground shaking and radiated seismic energy caused by the slip, or by volcanic or magmatic activity, or other sudden stress changes in the earth." (U.S.G.S).
HISTORY: "In the past 150 years, nearly 40 earthquakes of magnitude 6 or larger have affected Northern California." (Earthquake Country Alliance)
"Del Norte County is susceptible to regular earthquake activity, as evidenced by the five seismic events with a magnitude of 5.5 or higher experienced from 2000 through 2018." (Del Norte County Hazard Mitigation Plan)
Alhough they are infrequent, earthquakes of greater than magnitude 6 have occurred in Del Norte, including a magnitude 6.7 in 1873, with damage centered on Crescent City. The Mendocino Triple Junction to our south has produced several large quakes, including a magnitude 7.2 earthquake in 1992. A magnitude 9+ Cascadia Subduction Zone (CSZ) earthquake shook Del Norte County in 1700, and the subsequent tsunami inundated our coastal areas. The CSZ stretches roughly 600 miles from Northern California to British Columbia. Earthquakes generated by subduction zones are responsible for the largest earthquakes in the world, known as megathrust quakes.
SIGN UP FOR COMMUNITY ALERTS
Click on the red button to be informed of earthquakes, tsunamis, and other emergencies through Del Norte County's Community Alert System. When large earthquakes happen far away - such as in Alaska, Japan, or Chile, you may learn that a tsunami is coming hours ahead of arrival. REMEMBER! If you feel a strong and/or long earthquake, that's your natural alert that a local source tsunami may be imminent! It is important that you quickly move to a safe zone.
Residents should prepare to be self-sufficient for up to two weeks after a major earthquake, without the benefit of utilities or the assistance of response agencies. To prepare your household for an earthquake, view tips and steps from the Redwood Coast Tsunami Work Group. Securing furniture to interior walls, preparing a kit, and keeping a fire extinguisher handy are some simple steps you can take to prepare your household to withstand an earthquake and its aftermath.
FIND INFORMATION ABOUT RECENT EARTHQUAKES
Was that an earthquake???
Find information on the latest quakes near your location and around the world at the USGS website.
SIGN UP FOR MYSHAKE
Signing up for the MyShake app helps to ensure you will receive timely earthquake early warning alerts. App users can set a home base location and other locations to alert them of earthquakes near home, near loved ones, or other locations they spend time. Installing the app allows users become citizen scientists, helping to collect local ground motion data through their cell phones.