On September 16, 2015, the City of Medford hosted Dr. Althea Rizzo and Professor Eric Dittmer for a public earthquake preparedness presentation. The event was focused on what individuals, families, and local organizations can do to prepare for earthquakes, including the predicted Magnitude 9 event that was subject of a powerful New Yorker Magazine article in July 2015.
Althea Rizzo, PhD is the Geologic Hazards Program Coordinator for Oregon Emergency Management. Eric Dittmer is Professor Emeritus in Earth Sciences at Southern Oregon University.
You may stream a video of the session below.
The 1993 earthquakes near Salem and Klamath Falls were, fortunately, relatively small. However, the Tohoku Earthquake and tsunami striking Japan in 2011 exceeded a Richter Magnitude 9. Both are reminders that we need to be more aware of and prepared for earthquakes here in Oregon. In fact, recent geologic studies show that the Pacific Northwest has experienced earthquakes of a Magnitude 8 or 9, similar to the Tohoku event, every 250 to 350 years.
Clues to our earthquake history have been found in the rocks and sediments along the beaches and in the ocean bottom off the Oregon and Washington coast. Scientists from the University of Washington and Oregon State have been able to determine from tree ring analyses that many trees along our coast died all at the same time early in 1700 AD. They also found that a large Tsunami (seismic sea wave) hit Japan on January 26, 1700. These scientists estimate that the earthquake causing the Tsunami had a Richter Magnitude as high as 9 and was located just off the coast of Oregon and Washington along the Cascadia Subduction zone.
Other scientists studying ocean floor sediments at the bottom of steep slopes have found a pattern of undersea landslides probably caused by earthquakes occurring every 250 to 500 years. Unfortunately, the last one was recorded about 300 years ago. Based on this and other corroborating evidence scientists now believe that there is a 37% chance of a Mag. 8+ earthquake occurring in the Pacific Northwest within the next 50 years (Chris Goldfinger, OSU).
Even though these events are rare, it would seem prudent to be aware of the possibility of earthquakes where we live. Earthquake like the one affecting San Francisco in 1989 (Mag. 7) or Klamath Falls in 1993 (Mag. 6) released only a small fraction of the energy of a Mag. 8 or 9 event which could result in as much as 5 minutes of intense ground shaking. You should think about the following situations:
* Police, fire, ambulance and other first responders will be overwhelmed. Immediate rescue needs will be up to you, your neighbors and co-workers.
* Your family may not be together and you will want to contact them; but the phone system may be so overloaded that even emergency calls cannot get through.
* You and your family may need to be entirely self sufficient for weeks, if not months.
* You may not have electricity, water, food, shelter or essential emergency supplies.
* Buildings, streets, bridges, water/sewer and other infrastructure systems will likely be damaged. Electricity, natural gas and gasoline may not be available.
* You may have designated emergency responsibilities at your work; and, at the same time, you will be anxious about the well being of your family.
* Do you and others know where utility shut-offs are and how to turn them off? Do you need a special tool?
Public officials are updating their earthquake response plans. Earthquake drills are now required in Oregon public schools. The Oregon Department of Geology and Mineral Industries and the State Department of Emergency Management are promoting public awareness and preparation efforts locally and statewide. Clearly we need to consider the possibility of an earthquake before it happens.
REMEMBER even a large earthquake is survivable, if you are PREPARED. The following is a brief checklist of things to help you prepare for a future earthquake or similar emergency.
1) Check your work area for the best "duck and cover" location, such as:
under a sturdy table or desk, away from such hazards as glass and tall, heavy objects
2) Check your home and work place to address obvious hazards:
* place heavy objects as low as possible on shelves
* know where the windows and other large glass hazards are
* store hazardous chemicals and breakables carefully, ideally in cabinets with secure clasps
* Clearly label electricity, gas and water shut-offs, show others and obtain any tools needed to shut them off.
3) Know the best exit route(s) from your home and work. You may have to walk!
4) Make sure everyone knows emergency phone numbers and not to use the phone unless there is a serious emergency.
5) Prepare an emergency supplies "kit" and store in a safe, accessible location. Include flashlights, fire extinguisher, first aid kits and know how to use them. Learn and practice first aid. Think about food, water, medicines needed for several weeks! See web sites below for detailed lists.
6) Prepare a disaster plan and discuss these issues with family and co-workers. Practice.
1) Duck and Cover! (immediately, when you know it is an earthquake)
and hold on to your cover so it does not slide away from you. Cover your head and face away from windows.
* If you are inside, DO NOT RUN OUTSIDE!
* If you are outside, stay away from buildings, electrical wires, etc.
2) Try to remain calm - others may look to you for help.
95% of emergency rescues are thanks to your neighbors and co-workers!
1) Check to see if you and those near you are alright. Stay calm.
2) Note condition of the building; check for gas and water leaks (only turn off the gas if you smell it). Do not use phone except for reporting an emergency (call 911).
3) If inside, make sure those for whom you are responsible are accounted for are safe and, if mobile, can carefully exit the building with you.
4) Meet at an open area away from obvious hazards
5) Prepare for aftershocks
6) If the earthquake was strong enough to cause building damage, do not re-enter the building until given permission by a qualified expert such as a building inspector.
7) Take stock: Be prepared to review post earthquake realities such as: injuries, lack of utilities and communication, connecting with family, preserving food, water, etc.
8) Think in terms of weeks and months of disruption, nor just days.
Fortunately earthquakes are rare in Oregon, but we are in a window of a potentially large event. Just being aware of the possibility of a large earthquake and considering your actions will help you, your family and friends be survivors, not victims.
Some useful web sites for more information:
Oregon Dept. of Geology & Mineral Industries : Http://www.oregon.gov/dogami/Pages/index.aspx
(To view the DOGAMI 22 minute video on our earthquake setting, go to the Ashland Community Response Team (CERT) web site: www.ashlandcert.org scroll down to "Must watch".)
U.S. Geological Survey: http://earthquake.usgs.gov/learn/
Earthquake preparedness: www.oregongeology.org
Oregon Emergency Management: www.oregon.gov/OMD/OEM/pages/plans
For more information, contact Eric Dittmer (541) 941-1572
Revised September, 2015
* Provided in honored memory of Dr. Harry Smedes, co-author, geologist and wonderful, caring friend who passed away May 22, 2015