A swarm of underwater earthquakes with a magnitude of 3.2 to nearly 6 has occurred hundreds of miles off the Oregon coast in the past few days.
The earthquakes began on Tuesday, December 7, and as of Friday, December 10, nearly 90 tremors were recorded about 200 to 300 miles west of the Newport-Coos Bay area and about 10 kilometers deep, according to Office of Oregon Emergency Management (OMI).
In the following conversation, OMI Geological Hazards Program Coordinator Althea Rizzo gives us a specific overview of earthquakes and their significance.
The Chronicle : What is the significance of this latest swarm of earthquakes, what causes them and is it a warning of a massive earthquake to come?
Althéa Rizzo: It is an area with a lot of earthquakes, even more so than the San Andreas fault. The Pacific plate exceeds the Juan de Fuca plate, causing frequent, fairly weak earthquakes. We are in a period of heightened activity, but these earthquakes pose no risk to Oregonians. The seismic zone is very far from the Cascadia subduction zone, so there is no increased risk of a Cascadia event.
The Chronicle : You told us in previous interviews that the area off the southern Oregon coast is a frequent area for earthquakes. Is this the Blanco fault area and what is the difference between that area and the larger, more violent area that we have been told could lead to a massive earthquake?
Rizzo: Yes, that’s the Blanco fracture zone. The Cascadia subduction zone is where we are concerned. Subduction zones, where one plate dips under another, can cause very large earthquakes and tsunamis.
The Chronicle : We have heard that there is an active underwater volcano in the same area and this is what causes the earthquake swarm. Is it true?
Rizzo: This area has thermal vents, but there is no specific volcano in the area. There have been submarine volcanoes on the western edge of the Juan de Fuca Plate several hundred kilometers away.
The Chronicle : Do you find that despite these earthquakes and educational campaigns to help people prepare, the reality is that many are still unprepared?
Rizzo: Anytime we have earthquakes that grab the public’s attention, it’s a great time to remind people that earthquakes can happen anytime. It is important that families and households are prepared to be alone for a few weeks. Even just talking about the possible dangers is a start to being ready for Cascadia.
The Chronicle : What is your basic advice to people on preparation?
Rizzo: It doesn’t take a big earthquake to prepare; Oregon also experiences flooding, fires, ice storms, and hurricane-force winds. Most people would like to be a little better prepared for emergencies and disasters, but haven’t made the time or don’t know where to start. Often, taking the first step towards preparation is the hardest part. The holidays can be a great time to introduce low cost / no cost prep into the lives of friends and family. Some ideas include:
Make a plan. The most important first step in disaster preparedness is having a plan. FEMA offers several free prep products that can be downloaded or ordered from their website.
Store an emergency kit. Emergency kits are essential in the event of a disaster. Help your loved ones get started with theirs with a few essentials: Flashlights and extra batteries, cell phone chargers, and manual can openers are all necessary items that make great Christmas stockings.
Include children. OEM has released several Dark Horse comics describing what to do during specific disasters. These can be obtained from county emergency management offices, or you can download them from the OEM’s website. Most kids would also find a battery-powered or hand-cranked weather radio pretty cool.
Sign up for emergency notifications. Make sure your loved ones have signed up for OR-Alert. Print the website on a greeting card and add it to the bottom, or take a moment to list them when they come for the holiday celebrations.
Create a community. Deliver cookies to your neighbors? Use this time to discuss your emergency plans. It would also be a great time to offer essential groceries to neighbors who are older, have mobility issues, or are at increased risk of serious illness.
The Chronicle : What would be the best online resources to visit for more details on the Oregon earthquakes and how to best prepare for them?
The Chronicle : Please feel free to add any other comments you may have.
Rizzo: It’s important to know that you can be better prepared for emergencies with a little planning. Preparation doesn’t have to be expensive. Start by searching your house for the things you already have and organizing them. Earthquakes don’t have a season, but winter storms are coming.