The World has seen five significant earthquakes this year.
- Magnitude 8.8 OFFSHORE MAULE, CHILE February 27, 2010
- Magnitude 7.0 RYUKYU ISLANDS, JAPAN February 26, 2010
- Magnitude 6.9 CHINA-RUSSIA-NORTH KOREA BORDER REGION February 18, 2010
- Magnitude 5.9 OFFSHORE NORTHERN CALIFORNIA February 04, 2010
- Magnitude 7.0 HAITI REGION January 12, 2010
The one in Haiti has drawn the most news coverage due to the amount of destruction and the inability of the country involved to respond. Many people in the Northwest have responded with donations of aid and some have gone to help. My intent with this article is to remind us we also need to be prepared.
We live in earthquake country:
“At 9 p.m. on January 26, 1700 one of the world's largest earthquakes occurred along the west coast of North America. The undersea Cascadia thrust fault ruptured along a 1000 km length, from mid Vancouver Island to northern California in a great earthquake, producing tremendous shaking and a huge tsunami that swept across the Pacific. The Cascadia fault is the boundary between two of the Earth's tectonic plates: the smaller offshore Juan de Fuca plate that is sliding under the much larger North American plate.” This quote is from http://earthquakescanada.nrcan.gc.ca/histor/15-19th-eme/1700/1700-eng.php
If you are interested in learning more, google Cascadia Subduction Zone.
Are we collectively prepared, are we individually prepared?
There is evidence the Cascadia Subduction Zone has experienced 13 earthquake events at 300 to 900 year intervals, with an average of 590 years. It has been slightly over 300 years since the last one, so we should consider the Northwest due at any time for another major earthquake. What concerns me is that this isn’t talked about. A lot of our citizens are not aware they live in dangerous earthquake country, or they assume building codes will protect them and the government will rescue them. Why isn’t it a regular priority of local government to alert citizens about this danger and encourage everyone to take practical steps of preparation? I can appreciate that current budgets don’t allow local governments to spend lavishly on emergency planning, but an aware citizenry is a critically important step in earthquake preparation and costs local governments almost nothing. Comparing Haiti and Chile, it should be obvious that local preparedness makes a big difference in response capability.
Protection through Building Codes
We should not get complacent because we live in an area where building codes take earthquakes into account. As our collective knowledge about earthquakes has improved, our building codes have been updated to reflect this increased knowledge. In the U.S. building codes have been significantly updated in just the last 10 years to reflect a better understanding of earthquake hazards. But even these updates do not take into full consideration the potential damage for a magnitude 9 subduction quake lasting five minute or more. On top of that, most of our buildings and structures were built prior to these updates in building codes and even though they were designed with earthquakes in mind, the older building codes were even more inadequate than those we have today. An important feature of subduction zone quakes is that they last for a long time, often longer than five minutes. It is estimated the last Cascadia Subduction Zone quake was a magnitude 9 and it is anticipated that the next one will be similar. Therefore our better building codes will help the Northwest see less damage than Haiti, but if we have a five-minute magnitude 9 quake, even buildings designed to our current earthquake codes will be damaged. Structures designed to older standards will sustain even more damage.
As to government rescue, I for one am not interested in paying taxes to support the level of preparedness most people seem to expect. This is especially true when I can take simple steps in my own life to be prepared. At a minimum every household should have two weeks of food on hand, preferably in dry and canned goods as electricity could be an issue and refrigeration is dependent on that. Every household should have a way to purify water and a source for water that is not dependent on electricity. These are minimums. Are you prepared?
I am, however, in favor of paying taxes to support sound science about earthquakes and support local government to keep citizens informed of the risks on a regular basis. A periodic reminder would help me keep up my preparedness.
It pays to know the natural hazard possibilities for your area. If you live in a flood plain you should be prepared for floods and pay attention to weather conditions. If you live in the Northwest you need to understand the potential for very damaging earthquakes and take steps to be prepared.