Massive disasters that yielded major improvements in our understanding of earthquakes
There is a monster lurking under my home. It may strike at any moment, day or night, completely without warning. Scientific evidence can’t pin down this threat’s next intrusion into our lives, but it does suggest that it’s quite possible it may rip our house apart when it does. As a “rational” adult, I just slap the label “earthquake” on this monster and move along with my day. My children, on the other hand, aren’t so easily convinced, especially after seeing images of famous quakes from 1906 and 1989 in nearby San Francisco. As horrendous as those events were, one can take some comfort in the fact that we’ve learned a lot from those and other big earthquakes, meaning that similarly sized events happening today wouldn’t necessarily be as devastating as they were in the past.
One of the most famous earthquakes in history took place at 5:12 am on April 18, 1906. Seismometers had been invented, but they didn’t directly capture what is estimated to have been a 7.9 magnitude earthquake that shook San Francisco for 40 seconds. In fact, most residents of the city weren’t even sure what had happened, and are reported to have simply wandered out of their homes wondering what was going on. Buildings were obviously damaged, but the real destruction was still to follow thanks to broken water and gas lines which enabled over 60 fires to tear through the city, destroying more buildings than the quake itself. People struggled for days to fight the flames, even throwing dynamite into the mix to try to make firebreaks, but in the end the city would lose 3,000 lives and 28,000 buildings.
Lessons compiled in the Lawson Report
Fortunately, these losses were not entirely in vain. Andrew C. Lawson, the chair of the geology department at the University of California, Berkeley, seized the moment and convinced California Governor George C. Pardee to launch an investigation of what happened. At that point, people’s understanding of earthquakes was very shallow, and it was thought that they were simply anomalous shaking in the Earth’s crust. A team of scientists from all over California studied the aftermath of the quake and beyond, eventually releasing what’s now known as The Lawson Report, a document considered to be the backbone of our modern understanding of the seismic activity.
The Lawson Report marked the first time people understood how earthquakes fundamentally worked. Instead of random shaking, the team of researchers put together the model of tectonic plates pushing and rubbing against each other for the first time. Understanding that these plates sometimes stick and build up pressure before releasing it in a seismic event pointed people in the right direction for future disaster preparation. Geological maps were made to look for points where plate activity would be more likely, which has then helped shape how we build our cities. Even something as obvious as not building hospitals on top of fault lines is only feasible because we now know what geological evidence to look at.
Tsunami safety after record-setting quake
Unfortunately, the 1906 earthquake wouldn’t be the last time scientists had the opportunity to glean useful information from otherwise disastrous circumstances. While that earthquake was huge, the Valdivia earthquake of 1960 holds the record for the largest documented quake, with a magnitude of at least 9.5. This quake not only broke cities, but actually expanded the landmass of Chile as a whole by around 85 square miles. Individual towns were shifted west by as much as 30 feet in less than a minute, and the resulting tsunamis hit Hawaii in 12 hours, followed by Japan 12 hours after that.
Like the quake in 1906, the Valdivia earthquake yielded lifesaving information, as well as a deeper understanding of our planet as a whole. Seismometers around the world picked up movement from the quake, with energy moving through the various structures and materials of the crust, mantle and core like sound waves in an ultrasound image. Aside from enhancing our understanding of the world around us, this data also revealed how seismic energy can ripple through the ocean floor, creating tsunamis on distant shores. With that knowledge, it became possible to design tsunami warning systems, reducing risks in the future.
Obviously, nobody is rooting for more devastating earthquakes, but it’s good to know that in the last 100 years or so, humanity has done a decent job of finding some silver linings among the rubble.
Source: Lessons Learned From 1906 San Francisco Earthquake by Jan Sluizer, VOA News
