Two years ago this coming Monday (March 11, 2011), the Sendai quake and tsunami struck Japan, and shocked the world. The media gave it saturation coverage for weeks, especially when it appeared that several nuclear reactors were damaged and might leak radiation. It also affected me personally, because my new book Catastrophes! had just been published by Johns Hopkins University Press, and the PR agents for my publisher soon had me talking about earthquakes and natural disasters to every kind of media, from two stints on MSNBC, to radio appearances on BBC, NPR, and many local outlets, to an editorial written for the Los Angeles Times in just 2 hours before deadline (which led to a call from Mayor Antonio Villaraigosa). Everyone wanted to hear about the danger of quakes, and I spent most of my time on the air debunking the common fears and misconceptions.
Such fears are particularly common when it comes to earthquakes. People who have never experienced one are deathly afraid of them, even though they are extremely unlikely to kill anyone in the United States thanks to our building codes and construction. (The same is not true of many underdeveloped countries in Asia, where the loss of life can be extreme). I’ve run into all sorts of people terrified of quakes that they have never actually felt, yet they don’t even flinch at deadlier events like hurricanes and tornadoes. There are all sorts of legends associated with quakes, from “earthquake weather” (an urban myth) to the idea that California will fall into the sea (no, it’s sliding north to Alaska at a few cm per year on average) to the myth that fault lines look like huge deep chasms floored with lava as in the first Christopher Reeve Superman movie (no, they just form straight valleys on the ground: chasms are due to landsliding far from the fault). I’ve lived through every Southern California quake since I was born, including the 1971 Sylmar quake, the 1987 Whittier quake, and the 1994 Northridge quake. When I was in New York in August 2011, I even got to experience a rare eastern quake (the Virginia quake that shook the 10th floor of the Frick Wing of the American Museum while I was visiting), then ironically, I had to leave later that week and cancel my talk to NYC Skeptics on “Catastrophes!” because Hurricane Irene was on the way.
Quakes are particularly scary to people, probably for two reasons: they are unpredictable (unlike weather events, which give some warning); and they shake our confidence in terra firma, which we have all grown up to assume cannot move. Psychologists have shown that human beings are notoriously poor at judging relative risks, and assessing which threats are really serious and which ones are exaggerated. For deeply held psychological reasons, people are far more afraid of dying from a snake bite or in an earthquake, even though these are staggeringly improbable events for most people in the United States. Only 5 to 10 people die of snakebite each year, and earthquakes have killed an average of only 6 people per year in the past century. Yet because of these irrational psychological reasons, we are unjustifiably afraid of them. Because snakes trigger a primordial fear response in our brain, we are terrified of them. When we were small vulnerable hominids running across the African savanna, snakes were a real threat to us, because many African snakes, like mambas and cobras, are poisonous. But now that snakes are so heavily slaughtered in this country (despite the fact that most American snakes are non-poisonous), we are much more a threat to them than they are to us.
A more objective way of assessing real threats is to look at cold hard statistics, as an actuary or insurance adjuster does. An article by Borden and Cutter (2008) looked at deaths in the U.S. from all natural hazards from 1970 to 2004. Despite the fact there were several big California earthquakes (1971, 1987, 1994) and large hurricanes during that time window, you would never guess what the number one killer was. It was not even a topic that we think of as catastrophe, since it happens so often and so slowly. The top killers among natural hazards in this country are…. heat waves, storms, and winter!
Yes, earthquakes, hurricanes, and other extreme weather events are terrifying disasters, but the biggest killers are slow and subtle: heat waves and drought. Likewise, we take severe storms and the bitter cold of winter for granted since they happen so often, but they kill a lot more people than more dramatic events like tornadoes, hurricanes, and earthquakes. Notice that hurricanes, earthquakes, and landslides are near the bottom of the list with less than 2% of the total deaths. Even though hurricanes and tornadoes are potentially very dangerous, we usually have some warning of when they are coming, and most people take shelter or evacuate when warned. Volcanic events did not even make the list, since the small Mt. St. Helens eruption was the only deadly volcanic event in this country for better than a century.
Borden and Cutter (2008) also plotted the risk on a map of the U.S., organized county by county. If you asked anyone where the most dangerous places to live in the U.S. are, they would probably point to California with its earthquakes and landslides and brush fires, and maybe the Gulf Coast with its deadly hurricanes. But as the map shows, the opposite is true. Coastal California was one of the least hazardous in this regard (because we seldom get extreme killer weather of either hot or cold variety). The most deadly regions turned out to be the Deep South, where severe heat and humidity is common, and where occasional hurricanes only add to the carnage. Also dangerous was “tornado alley” in the southern Plains, with heat, drought, and tornadoes, and the southern Rocky Mountain region, with its desert heat and flash floods. The northern Plains and Rockies and Midwest were also death “hot spots” due to extreme cold and drought and occasional flooding. The rest of the country did not show any striking trends one way or another. What you don’t see is any strong correlation of high death risk with the fault zones map or even with the Gulf Coast-Florida hurricane zone.
Let’s put that in an even broader perspective. Many people are terrified of earthquakes and tornadoes and hurricanes, but these evens are not something to lose sleep over except when there are clear warnings that a hurricane or tornado is coming. We should be more careful and worried about heat waves and severe winter storms, but we’re so accustomed to these each year that we don’t realize how deadly they are. But worrying about natural disasters looks absurd in the face of where the real risks come from: your cheeseburger and French fries, your car, cigarettes, and all sorts of things you encounter every day. Borden and Cutter (2008) point out that for the 20,000 people killed by natural disasters in the U.S. during the study period from 1970 to 2004, there were 652,000 deaths from heart disease alone (more than 30 times the natural disaster total)! There were 600,000 deaths from cancer (also 30 times the total from natural disasters). Of cancer deaths, almost a third were from lung and other cancers due to smoking. Colorectal cancer, pancreatic cancer, prostate cancer, and breast cancer were the other biggest killers. There were 143,000 deaths from stroke, 130,000 from chronic lower respiratory diseases (bronchitis, pneumonia), and even 117,000 killed in accidents (mostly car accidents). If we really took the issue of risk seriously and evaluated it objectively, we would do well to worry much more about our diet and exercise, get frequent health checkups, stop smoking, and modify our driving habits. We may fear death in an earthquake or hurricane, but lunch, cigarettes, and driving are much more deadly to you!
- Borden, K.A., and Cutter, S.L. 2008. Spatial patterns of natural hazards mortality in the United States. International Journal of Health Geographics 2008, 7:64