Chile - Final Hazards Blog

Chile is subject to many kinds of natural disasters due to its geographical situation.  After weeks of researching natural hazards in the country of Chile, I have concluded that the main natural hazards impacting this country are due to earthquakes, tsunamis and volcanoes.  These three would be considered a priority to the country of Chile because of the frequency and the severity of damages caused in this region.  

When it comes to earthquakes, Chile is one of the most seismically active countries in the world. This country is a hotspot for earthquakes because it is one of the few places where the three major plates meet called a triple junction.  The Nazca plate borders the South American Plate for most part of the continent, but towards the tip of the continent and bordering Chile is the Antarctic Plate.  The Nazca plate is submerged below the South American plate, and the pressure building up between the two plates is eventually released in the form of an earthquake.

Chile has a long history of tsunamis.  Chile’s most recent big tsunami happened on February 27, 2010, when a magnitude 8.8 earthquake, centered offshore caused a tsunami with a maximum wave height of some 95 feet.  Chile sometimes generates Pacific-wide tsunamis, but it is also vulnerable to tsunamis from other earthquake centers around the Ring of Fire.

Volcanoes are another dangerous hazard in Chile.  Even though significant damage has not been reported due to their eruptions, I still considered it a danger in Chile due to the volume of volcanoes in this country.  Chile has more than 2000 volcanoes and about 500 are still active.  Chile’s volcanoes include the highest in the world, Ojos del Salado. One of the most recent eruptions was The Villarrica volcano in southern Chile.  In 2015, this volcano erupted and spewed ash and lava up to 1,000m (3,300ft) into the air. 

Of the three, the hazard I would target first are the earthquakes in Chile. Currently, Chile uses the GNSS network to determine the magnitude of an earthquake.  Then the GNSS stations send communication to the Emergency Alert System (SAE).  This system is designed to alert Chilean residents of possible national emergencies. It is primarily used after earthquakes, when there exists a possibility of a tsunami, or during volcanic eruptions. The idea behind the system is to give people time to prepare and evacuate.  It is an automatic system that sends alerts to all phones in a certain area. channels to alert residents.  However, in order to mitigate damages, I would suggest using a new satellite-based early warning system called G-FAST.  This early warning system uses the ground motion near fault lines to trigger warnings.  The precision and timing of the G-FAST could add valuable information and time to predicting high magnitude earthquakes. 

 

If I were to construct a house in Chile, I would select the northern region of Chile.  A lot of the southern regions of Chile have been hit with earthquakes.  Even though they have been rebuilt and modernized I would prefer to stick to the north where the climate is better and there is less structural crowding.  Most of the significant damages due to earthquakes have occurred in central and the southern regions of Chile, so I would avoid those and move north.  

References:

Why Chile is so prone to severe earthquakes • Earth.com

Natural risks in Chile - Expat.cl

Volcano Watch — Surprise Eruption in Chile Sparks Interest in National Volcano Early Warning System | U.S. Geological Survey (usgs.gov)

Earthquakes: What can we learn from Chile? – DW – 11/16/2020

 

 

Coastal Hazards in Chile

The Chilean Coast is the area in the Southeastern Pacific Ocean.  It has a long coastline that has several rivers that run into the ocean. One of the most notable causes for coastal hazards on the Chilean Coast is due to earthquakes.  Chile is a hotspot for earthquakes because of the Nazca plate, a tectonic plate which moves eastwards and collides with the South American plate off the Chilean coast.  Due to the frequency and strength of earthquakes, coast erosion, tsunamis and tidal waves become a factor.  

Coastal erosion is defined as the wearing away of land or the removal of coastal wetland, beach or dune sediments by wave action, tidal currents, wave currents, or drainage.   According to ScienceDirect, coastal erosion may be the next hazard facing central Chile.  They reported that the coasts of central Chile are increasingly affected by human activity. To date, there are no clear symptoms of shoreline change in the area; however, the incidence of recent extreme storms, in conjunction with an increase in urban area, may have created a new coastal hazard in addition to earthquakes and tsunamis.  In this study, four urban beaches were analyzed on a decadal scale. Satellite images showed shoreline retreat and an increase of erosion rates.  They went on to conclude that the erosive trend found in the last decade suggests that this coast could deteriorate if such factors are maintained or intensified.

Tsunamis and Tidal Waves are another factor that the Chilean coastline must contend with frequently.  As reported in the Tsunami Historical series, Chile was struck by the largest earthquake ever recorded by instruments on May 22, 1960, at 3:11 pm.   The earthquake struck southern Chile with a magnitude we now know to be at least 9.5. This earthquake generated a tsunami that traveled through every ocean on earth, though large, dangerous waves only impacted the coastlines around the Pacific Ocean. Chile suffered the greatest impact, with tsunami waves reaching as high as 25 m or 82 ft., killing an estimated 2000 people.  Since then, there have been numerous tidal waves that have struck the Chilean coast causing structural damage and significant loss of life.  

As far as measures Chile has taken in order to alert people and prevent coastal hazards, unfortunately, not a lot has been done.  There are warning systems for earthquakes and tsunamis, which have aided in those events.  However, nothing concrete has been established in regard to coastal erosion, ScienceDirect has reported that, “Emerging efforts have been made to establish the current state and future projections of coastal erosion in Latin America, however, there is no detailed analysis of erosion processes in central Chile, where unique conditions associated with tectonic processes, climate change and human pressure combine. Studies addressing the past and future behavior of oceanographic variables that affect erosion are scarce.”

Sources:

Coastal erosion in central Chile: A new hazard? - ScienceDirect

Think Hazard - Chile - Coastal flood

Coastal erosion in sandy beaches along a tectonically active coast: The Chile study case - Carolina Martínez, Patricio Winckler Grez, Roberto Agredano Martín, César Esparza Acuña, Iván Torres, Manuel Contreras-López, 2022 (sagepub.com)

Chilean Coastal Sea - The Seas Project (weebly.com)

Tsunami Historical Series: Chile - 1960 - Science On a Sphere (noaa.gov)

Extreme Weather in Chile

 Chile is no stranger to extreme weather and in recent years, Chile has experienced some of the most drastic changes due in part to climate change.  According to SpaceRef, “In the northern part of Chile one of the world’s driest deserts is flooding and in the south some of the planet’s wettest woodlands are burning.”  The desert flooding is due to the rains in the Andes.  The water is pouring into the Atacama Desert which is normally one of the driest places on Earth.  However, due to the flooding, the waterfall that had run dry for 10 years is now once again flowing.  In the south, the record-breaking temperatures have caused forest fires burning thousands of acres of land.  The high temperatures, low humidity, high winds and drought conditions are the reason why the wildfires are so large.  

This is a NASA satellite image of the fires in the southern region of Chile

What has Chile done about the recent extreme weather conditions that have impacted the country?  In the south, where the extreme temperatures have caused hundreds of fires, the government has declared some regions a disaster area to assist with funding to combat the destruction.  In the northern region that has been impacted by flooding, President Sebastian Pinera declared a “zone of emergency” to assist the region devastated by the heavy rains.  Moving forward, more needs to be done in Chile to keep up with climate change.  In a Straight Times article, Park Williams, a hydroclimatologist  at Columbia University in New York quoted, "Chile needs to be thinking about how to adapt to climate change, as it has such an isolated climate that makes it more vulnerable to droughts.  For the last several decades, temperatures have risen, and precipitation has declined in central Chile, making it more susceptible to wildfires."

Time will tell if Chile can afford to keep neglecting the ongoing issue of extreme weather.  For now, it seems that there are no pro-active solutions to the problem.    

References:

Extreme Weather in Chile Causing Catastrophic Fires - SpaceRef

https://www.nasa.gov/image-feature/goddard/2019/extreme-weather-in-chile-causing-catastrophic-fires

World's driest desert floods as extreme weather hits Chile | The Straits Times

Mass Wasting in Chile

The general term for mass wasting is any process of soil and rock erosion that is driven by gravity.  There are no specific triggers although there are some factors that can contribute to the severity or frequency of mass wasting.  Some of the most common examples of mass wasting are landslides, rock falls and mudslides.  The mass movements can be highly destructive and dangerous.  

In Chile, debris flows such as landslides are often triggered by heavy rainfall.  Therefore, the middle and southern regions are more susceptible to mass wasting.  Those areas have higher amounts of precipitation.  However, the northern regions of Chile are at low risk due to the extremely dry climate.  According to Think Hazard - Chile - Landslide , Chile is classified as high susceptibility for landslides and also has impacts due to climate change.  This website states that, “Climate change is likely to alter slope and bedrock stability through changes in precipitation and/or temperature. It is difficult to determine future locations and timing of large rock avalanches, as these depend on local geological conditions and other non-climatic factors”.  

Unfortunately, Chile does not have a warning system or preventive measures for these types of hazards.  In the past, the country has declared a state of emergency after the hazard and then action is taken to assist people.  For remote locations, airlift rescue is sometimes required to evacuate people.  Due to the fact that Chile is prone to this type of hazard, it should be a priority to government officials to expand their warning systems and take precautionary measures.  

The aftermath of the landslide at Villa Santa Lucia in southern Chile

Sources:

Think Hazard - Chile - Landslide 

AGU Blog

Volcanic Activity in Chile

According to the Smithsonian website, Chile has 91 Holocene volcanoes.  Ten of those have erupted within the last 20 years.  Most large volcanoes in Chile are stratovolcanoes also called composite volcanoes. They are tall and cone-shaped made up of many layers of hardened lava and volcanic ash. Cinder cones are smaller than stratovolcanoes and are steep and cone-like in shape. In Chile there is also plenty of hydrothermal activity and is found where there is volcanic activity under the Earth’s crust. Geyser is a type of hot spring that erupts regularly, throwing hot water and steam into the air. There are also hot springs and fumaroles in Chile.  

The Southern Andean Volcano Observatory (Spanish: Observatorio Volcanológico de los Andes del Sur), also known by its acronyms as OVDAS, is part of Red Nacional de Vigilancia Volcánica, a program of the Chilean National Geology and Mining Service to watch the 43 most dangerous volcanoes of Chile. In 2012, there were 30 volcanoes under observation.

Based off the USGS website, the eruption of the Chaitén Volcano in Chile, on May 26, 2008 influenced the Chilean government to plan a National Volcano Early Warning System (NVEWS) modeled after a 2005 USGS report proposing a monitoring strategy for U.S. volcanoes. The strategy ranks hazards posed by volcanoes into threat levels, assesses the monitoring gaps, and recommends upgrading the monitoring capability according to the threat level.  This monitoring network assists them to transmit data in real time to help warn the public of further eruptions.  This system will ensure proper evacuation time and could save countless lives.    

Sources:

Volcano Watch — Surprise Eruption in Chile Sparks Interest in National Volcano Early Warning System | U.S. Geological Survey (usgs.gov)

Global Volcanism Program | Chile Volcanoes (si.edu)

List of volcanoes in Chile - Wikipedia

Volcanoes of Chile | Chile Culture

Map-of-active-volcanoes-in-mainland-Chile_Q320.jpg (320×320) (researchgate.net)

Earthquakes in Chile

     Chile is a hotspot for earthquakes because the Nazca plate, a tectonic plate which moves eastwards with a rate of 6.6 cm per year, collides with the South American plate off the Chilean coast.  The Nazca plate is submerged below the South American plate, and the pressure building up between the two plates is eventually released in the form of an earthquake.  The strongest earthquake ever recorded by modern instruments was a 9.5-magnitude quake on May 22, 1960, which was centered offshore in southern Chile, where it set off a huge tsunami.

    After being hit by the planet’s largest-ever recorded earthquake back in 1960, Chile developed strict anti-seismic building codes. Despite this, an 8.8-magnitude earthquake in 2010 wreaked destruction in southern and central parts of the country. More than 500 people were killed by the quake and the tsunami that followed. More than 200,000 homes were flattened. Things had to change again. Building codes were updated so structures could better withstand seismic waves. Strong columns and weak beams meant buildings would have a better chance of swaying with the tremors and avoiding collapse. Pressure was also exerted on planners for any new buildings to be constructed further from the sea.

    Also, having learned from the past, better early warning systems are now in place. The National Seismological Centre in Chile functions around the clock since the government invested in a network of sensors throughout the country to record seismic activity. If there is going to be a big one, they’ll be alerted.  Chile survived a big quake with relatively few casualties because it was ready for it. For many years now, local groups around the country have been familiarizing themselves with disaster preparedness plans, practicing countless earthquake drills and running through evacuation routes time and time again. The result? More than one million people were evacuated from coastal areas in a matter of hours, escaping the tsunami waves, some of which were 15 feet high in the region of Coquimbo.

Sources:  

Earthquake in Chile (nasa.gov)

Seismic Monitor - Recent earthquakes on a world map and much more. (iris.edu)

What Chile did right - Chile | ReliefWeb

Why Chile is so prone to severe earthquakes • Earth.com

Tectonic Plates and Chile

 Triple junction

While most places have trenches where two large tectonic plates meet, Chile is one of the few places where three major plates meet. In other words, it is a triple junction.

The Nazca Plate, borders the South American Plate for most part of the continent. But towards the tip of the continent and bordering Chile is the Antarctic Plate.

The Nazca Plate is subducting beneath the South American Plate at a rate of 80 mm a year; the Antarctic Plate is subducting beneath the South American Plate at a rate of 20 mm per year.

What makes Chile suffer from very powerful quakes is the fact that the angle of subduction (diving) by the Nazca Plate below the South American Plate is very shallow — 5 to 15 degrees.

The place where one plate subducts beneath another is called a trench. The place where new ocean crust is formed is called a ridge. It can be seen as the recycling of the ocean crust — new ocean crust is formed at the mid-oceanic ridges and is consumed (destroyed) at the subduction zones (trenches).

Chile: where three tectonic plate boundaries meet | Science Chronicle (journosdiary.com)

https://spotlight.unavco.org/station-pages/conz/eo/scienceImage1.png