Charm and Dangers of Arequipa

posted in: Research | 0
The vanguard team of In Harm’s Way’s first expedition to Peru. From left to right: Dr. Herrera (Niyeli’s father), Niyeli Herrera, me and Brian Petersen.

Meet the Team

In Harm’s Way is exploring how it can help the mountain nation of Peru prevent its many natural hazards from causing catastrophic natural disasters.

One of our volunteers, Niyeli Herrera, is from Peru. She organized the expedition through the many contacts she has with family and friends there. For example, one of the family friends is a geologist who studies geohazards in Peru. Niyeli also invited one of her friends at BYU, Brian Petersen, to join the expedition. Brian is graduating this year from BYU with a degree in computer science, and is fluent in Spanish.

Our team of three started the expedition in Arequipa, which is one of the most at risk cities in Peru. The security briefing I received before coming to Peru warned that Arequipa is the kidnapping capital of the world. However, this threat is not near as bad as those from floods, earthquakes and volcanic eruptions that have happened here in the past.

Exploring Arequipa

Arequipa is the second largest city and economic powerhouse in Peru. It was founded in 1540 AD in an oasis at 2,300 meters elevation around 80 km inland. The constructed area remained relatively compact around the historical center with a population of 86,000 in the 1960’s. Then, the human disaster started: from 1970 to the present Arequipa experienced a growth rate of 400% and now has around 1 million inhabitants crowded into an intermountain basin bounded by active faults and ruled by an explosive volcano.

Most of the population growth is in the form of poorly designed suburbs and illegal settlements on the lower slopes of El Misti and Chichani volcanoes, which have erupted in the recent past and buried the whole basin in ash several times. The entire city is now built on these deposits. Surrounding the volcano is an apron of debris flows, and flood and lahar deposits that the newer suburbs call home. For example, floods and debris flows rushing down the mountain into its gullies are channeled into the new suburbs and commonly into the heart of the city. Since all of the growth started there have only been small events, but the stage is set for more extreme events as temperatures continue to warm.

If the hazards already mentioned are not enough, Arequipa is only 150 km from the Peru-Chile Trench, which is susceptible to mega-earthquakes. Since most of the city is built on unconsolidated volcanic and flood deposits its poorly reinforced buildings will likely not perform well during the sustained ground motion from a major earthquake.

Hazard maps are available for the city, but how does this research translate into prevention against a backdrop of uncontrolled growth and poor building practices? This question is connected to a much more deeply rooted question of how to address the human disaster happening that makes places like Arequipa so vulnerable to even small natural events that lack of resilience.

Other Andean countries, such as Chile and Columbia, have shown that it is possible to mitigate the disaster potential many of these hazards if there is the political will.  It is never too late to start incremental prevention.

We witnessed some small eruptions of Sabancaya on May 22-23. Sabancaya, which means "tongue of fire" in the Quechua Indian language, is to the NW of Arequipa.
A retired military tank in Arequipa stands as a symbol in this community of what it has gone through. Looking at dangers ahead, greater preparation is needed.
El Misti or “The Ruler” looming above the ever-expanding city of Arequipa, Peru. The rolling hills in the foreground consist of ashflow and debris flow deposits from the active volcano.
Follow Ron Harris:

Ronald Harris, the founder of In Harm's Way is passionate about helping to saves lives through disaster mitigation.

Leave a Reply

Your email address will not be published. Required fields are marked *