In the United States, it is easy to forget that earthquakes can cause much more damage than hurricanes. Thanks to modern engineering, most structures in American earthquake-prone regions resist light and moderate earthquake damage easily. Although dozens of earthquakes rattle these regions every month, they usually don’t cause more damage than a few broken coffee mugs. Even after including the Great San Francisco earthquake of 1906, only about 4,000 people have died in American earthquakes in the past 200 years. The San Francisco earthquake alone accounts for 3/4 of those deaths.
Although they are much less common than earthquakes, American hurricanes have also been much more deadly. As recently as 1900, the Galveston hurricane alone killed between 6,000 and 12,000 Americans. Even in the modern hurricane forecasting era, Hurricane Katrina killed at least 1,836 people. These kinds of numbers make hurricanes terrifying forces of nature.
However, these mortality statistics are distorted by American geography, American engineering, and sometimes even by failures in American infrastructure. While most Eastern Seaboard regions have experienced a dangerous hurricane sometime in the past couple of decades, no part of the United States experiences strong earthquakes with the same frequency. Earthquakes of magnitude 6 or higher are rare even in California, where lesser quakes are mostly ignored. This means that in the United States, hurricanes are much more uncommon than damaging earthquakes, but they always make the news.
On a global basis, the reverse is true. Earthquakes are responsible for millions of deaths around the world. By far, the deadliest known hurricane was the 1970 Bhola cyclone in Bangladesh, in which half a million people lost their lives. However, earthquakes with casualty tolls in the hundreds of thousands are not rare. There seems to be at least one every year.
This is because strong earthquakes are more common than strong hurricanes, and can cause much more damage. Here are some of the reasons why they kill so many more people and cause so much more damage.
Surprise
With modern forecasting techniques, a hurricane can be anticipated for many days in advance. The exact path and intensity can’t be known with certainty, but everyone can know that a hurricane is coming to the general region and make preparations or evacuate.
Science can’t predict earthquakes with the same precision. The best science can do is to identify earthquake-prone regions and measure the amount of stress which has built up along the fault line. That stress releases in a roughly predictive cycle, but that only means that an earthquake is going to happen in the region sometime in the next dozen or hundred years. This doesn’t help for day to day planning.
Geography
The most damaging hurricanes occur in low-lying places with very high poverty levels, such as Bangladesh. Some of Bangladesh’s coastal regions have beaches up to 75 miles inland. Until recently, there were few provisions for public shelter from cyclones.
However, earthquakes can cause extreme damage anywhere there is a fault line. Because of their proximity to rivers and productive mines, many fault lines run near major cities. Nearly all cities, especially old European and Asian cities, have large sectors which are not built to modern earthquake standards. In these conditions, even a moderate earthquake which strikes at night can be catastrophic.
Foundations and walls
Earthquakes shift the earth under a house. Even moderate earthquakes can damage a well-built foundation. If the foundation gives way, the rest of the house will fall down. Walls with little flexibility, such as most stone construction, will also collapse.
Hurricane winds cause the most damage to roofs and walls, because those have the most wind resistance. Everything the wind blows can land with full force against a wall. However, most houses with good foundation footings can resist most hurricane-strength winds. Windows are the most vulnerable parts of walls to direct wind and wind-projectile damage, so people usually board them up.
New fault lines
Hurricane paths are well known by now. No hurricanes can venture far inland, and extremely few hurricanes drift even a few degrees off the beaten path. This makes it possible to plan ahead.
However, even after an area has been geologically surveyed, a new fault line can still open up. If that fault line opens up directly under a structure, that structure will be twisted out of shape or may even fall into the new chasm. This can completely wreck previous engineering plans.
Other effects
Hurricanes can spin off tornadoes, but these have very small damage paths. Even storm surges are limited to low-lying coastal areas. However, subduction earthquakes can spin off tsunamis, which can cause damage around the world. During the 2011 Sendai earthquake in Japan, the resulting tsunami caused far more destruction than the earthquake itself. Besides its terrible damage along Japan’s northeast coast, it also killed people as far away as California and Chile.
Conclusion
Both earthquakes and hurricanes can be extremely dangerous. Their ability to cause damage and kill should be respected. In both cases, modern engineering can mitigate some of that damage, if the earthquake or hurricane is not too severe. However, the damage which can be caused by the strongest earthquakes and hurricanes is still beyond the abilities of modern technology to mitigate.
