Tuesday, August 26, 2014

Is the Big One coming?

The following query arrived just a day before the M=6.0 Napa, California earthquake of 24 August 2014. Unfortunately, I could not respond to the obviously nervous individual until after that event took place. The bottom line is that non-human risks change little over time – they are just there, but they can be dealt with. However, people tend to obsess over what scientists call “high-impact-low-probability” events – like a shark attack or an earthquake along the so-called Pacific Ring of Fire.

Q: Hello I live in California and currently I'm getting very scared with all the current activity around the ring of fire. My question is whether this is normal activity or warning signs for bigger earthquakes to come, or even the "big one"?
-          Dolores L

A: The activity you are noticing is normal - it has been going on for millions of years. Sometimes it seems more exciting in some locations than normal, but this is still normal.
When you write of a "big one", this is also normal: we are expecting a subduction mega-quake in the Pacific Northwest anytime in the next one day to 300 years. Some older schools are being earthquake-retrofitted in Oregon as I write this. The Earth's crust is an active place, and the truth of the matter is that no matter where you live there is some degree of local (potential) hazard everywhere, whether hurricanes, volcanoes, domestic violence, earthquakes, drought, floods, car-accidents, or tornadoes.

The rational way to deal with these is to evaluate each hazard carefully – and there are public agencies like the USGS that do this all the time, very conscientiously. Once you know what the risks are – and most of the "big ones" are high-impact-low-probability – then you can plan accordingly. I bought my home on a slope for the view, but I checked the foundations carefully before I paid for it. I also paid an extra 15% earthquake premium on my homeowners insurance.

To put things in perspective: people react strongly to learning that a swimmer was killed by a shark, but 10's of thousands of sharks die brutally at the hands of humans each year rather than the other way around. Compare the 1 - 3 human shark-bite deaths to over 35,000 highway deaths in the United States last year. While seat belts, speed limits, and no-texting are theoretically enforced, no one seems to get particularly excited about this huge killer.
Another perspective: My father, before he died of lung-cancer, lived in a high-rise apartment in San Francisco less than 10 miles from the San Andreas Fault. I once asked him if he worried about it much? His response opened my eyes. “Listen,” he said, “I could enjoy the view of the Bay from here, or I could hunker down in a basement somewhere and worry constantly. Long ago I chose the former.”

Bottom line: the world is NOT about to end. Study your own personal risks, and then take rational precautions to mitigate them as much as possible without going overboard. Just taking any steps will lessen your worries, because you will be actively doing something about them. This could include putting up a supply of drinking water and food to last you during a local or regional disaster. Or better yet, a years supply so you can also help your neighbors.