Studying surface cracks from earthquakes in the Atacama Desert, Chile.

When news hit about the catastrophic floods in Chile last month, I was immediately brought back to my field seasons in the Atacama studying earthquakes. Though I had grown up in a region where tornado sirens were the norm, the very real threat of natural hazards – from earthquakes to tsunamis – played more of a role in daily life in that region than I was used to. Add the potential threat of floods and landslides, and the region feels like an academic playground for studying natural hazards.

I started this post intending to write something about the surprising relative risk of various hazards in the Atacama – rain versus earthquakes – but looking at the photos I was pulled back in to more than the scientific connections with the region. Adding the more recent earthquake in Nepal into the mix took me even further from the post I had originally intended to write. I was pulled back in to the personal connections that I had formed while in Chile studying earthquakes, and reminded of the importance of keeping a place for the human component in studying natural hazards.

While spending the night in Iquique, Chile to get gas, groceries, and a shower between weeks in the field, I had camped out in the hotel lobby for the wifi. I was typing away on my laptop, maps spread across the tables and seats around me, when I noticed that the hotel desk clerk was standing in front of me. In a mix of weak English and even weaker Spanish, we discussed that I was a graduate student, that I was a geologist, and that I was studying earthquakes. After a few moments of pause, he sat down. Though he worked in Iquique, he lived in the city at the top of the cliff, Alto Hospicio, and had to drive down every day. He had been on that narrow cliff road when the last earthquake hit. He had jumped out of his car, which he was afraid was going to shake off the edge and was paralyzed between the threat of falling rocks above him and the edge of the cliff below.

View from the coastal cliff road between Iquique and Alto Hospicio.

He made it through with only a little damage to his car, and went on with his life. But he looked me in the eye and said that the earthquake hadn’t been that big. I agreed. He said that the scientists said that there would be much bigger ones and possibly soon. At the time Iquique was solidly in a seismic gap on the plate boundary that had a 100-150 year recurrence interval on average for earthquakes over magnitude 8. During that field season we were 138 years into that timeline, so again I had to agree. I asked him if he ever considered leaving. He said no, that this was his home.

Later that same summer I was on my way back to the states and had a 12 hour layover in the Santiago airport. I ended up sharing a table with a woman who had been in the 1960 Valdivia earthquake. At 9.5, it was the strongest earthquake ever recorded. It happened at night and she remembers she and her sister being thrown around their room “like toys,” being hit by beds and other pieces of furniture. She recalled how there had been so much destruction that many of them were basically living in the town square. When the first care packages arrived from abroad they were primarily school supplies, but she and the other kids took it as a sign that at least the outside world knew they were there. She and her family still live in the same neighborhood.

We said goodbye, I caught my plane, and spent the next months and years staring at data and trying to understand the seismic history of the region from an increasingly academic perspective. Even the photos I have (like the ones in this post) are quite sterile. I probably haven’t even thought about my conversations with those two people in years, but looking back I know that they provided an important link that I didn’t previously have with my work. They provided perspective.

The recent news coverage of the floods in Chile have called the rain “torrential” or the storms “extreme.” Given the damage they created, these adjectives seem appropriate. But just how much rain was there? The Atacama receives an average of ~1mm of rain per year. But, like most averages, that does not mean that every year there is about ~1mm of rain. In the Atacama most of the rain comes in storms that occur every few decades. This most recent storm had ~0.9 inches of rain fall over ~12 hours. Considering that the 2013 floods in Colorado were the result of 9 inches one day and 17 inches total, less than an inch doesn’t exactly sound “torrential.” But when there are no trees or grass to hold soil in place, when rocks simply weather into layer of dust so thick that your truck can get stuck if you drive too slowly (as mine did), that seemingly small amount of rain can flow freely and mobilize sediment for hundreds of miles without anything getting in its way.

Surfaces in the Atacama Desert often break down into thick layers of fine sediment. With almost no vegetation to hold it in place, this sediment can mobilize quickly and easily when exposed to rain.

Less than an inch of rain affected more than 11,000 people and took 17 lives. By comparison the nearby 2014 earthquake was a magnitude ~8.2, displaced about 80,000 people, and resulted in 6 fatalities. An earthquake of that magnitude would have been the largest to hit the continental US since 1700.

As an outsider to the region, it is easier to sympathize with the risk of earthquakes, tsunamis, or volcanoes than with a bit of rain. But with any natural hazards it quickly becomes clear that not all risks are created equal, and the potential threat has as much to do with the culture and infrastructure of a region as it does the climate or tectonic setting.

The previous examples include two different hazards – rain and earthquake – in the same region, but it can be even more revealing to look at comparable hazards from places around the world. In 2010 there were two earthquakes less than a month apart. One was a magnitude 8.8 in central Chile, where building codes are relatively strict regarding earthquake safety. There were 507 recorded fatalities. The other was a magnitude 7.0 in Haiti. Even though this earthquake released almost 100 times less energy than the one in Chile, over 316,000 lives were lost.

These are compelling arguments for having important conversations about building codes, but those conversations need to take a back seat for long enough to take care of those affected. We need to remember not to just think of a region as a particular level of hazard risk, but as someone’s home.

On the news it is easy to write off the results of many disasters, saying that with people living that close to a volcano, on an active fault, next to a river, etc were bound to be faced with disaster eventually. But ask those same people to assess the risks in their own home town and they may start to sing a different tune. When I was in high school a tornado came through my neighborhood, imploded the windows of a house down the street from mine, and ripped the roof off of our middle school. At the time the damage felt very personal and very traumatic – and a conversation about building codes before victims would not have felt welcome. None of my neighbors considered moving away as a result.

Understanding the forces behind various natural hazards can be complicated enough, even without taking the human factor into account. So it can be tempting to think about the academic part on its own. But there is a balance that we can strive for, where the science can be used to make life for people better or safer in the future without forgetting about the importance of the individuals dealing with the effects of a disaster now.

Sources:

https://earthquake.usgs.gov/earthquakes/eqarchives/year/byyear.php

http://www.theatlantic.com/photo/2015/04/devastating-floods-hit-northern-chile/390024/

http://www.bbc.com/news/world-latin-america-32114822

http://www.theguardian.com/world/2015/mar/30/chile-floods-17-dead-20-missing-aid

http://en.wikipedia.org/wiki/2013_Colorado_floods

http://en.wikipedia.org/wiki/2014_Iquique_earthquake

http://en.wikipedia.org/wiki/2015_Northern_Chile_floods_and_mudflow

http://coflood2013.colostate.edu/

Images are my own