Massive Earthquake off the Coast of Chile Triggers Tsunami Warnings in the Pacific

An 8.2-magnitude earthquake off the coast of northern Chile on April 1, 2014 was followed by at least a dozen significant aftershocks, including one with a magnitude of 6.2. This activity initially generated tsunami warnings across the Pacific, but the warnings were later canceled except for the coastal regions of Chile and Peru, according to NOAA’s Pacific Tsunami Warning Center.

Tsunami waves of more than 2 meters (6 feet) came ashore on the coast of Pisagua, Chile and 2.13 meter (7-foot) waves were reported in Iquique, Chile, according to the PTWC. The U.S Geological Survey reported the quake major quake was centered offshore about 96 km (60 miles) northwest of Iquique, at a depth of 20 km (12.5 miles).

At the time of this writing, the quake has reportedly caused only minor damage in Chile with two possible casualties, but several people are missing. There was a small landslide, several large fires, along with damaged boats and some flooding in Iquique due to the tsunami, according to Earthquakereport.com.

Chile’s National Emergency Office tweeted Tuesday night that it was asking everyone to evacuate the country’s coastal areas, and reports in the news and on social media said that the evacuations were orderly.

This earthquake follows several weeks of seismic activity in the South American Pacific region. On March 16, a 6.7-magnitude earthquake struck 60 km (37 miles)northwest of Iquique, according to the USGS. A 6.1-magnitude hit the same area one week later.

Chile is one of the most seismically active countries in the world, and is along the so-called “Ring of Fire,” an arc of volcanoes and fault lines circling the Pacific Basic that is prone to frequent earthquakes and volcanic eruptions.
The strongest earthquake ever recorded on Earth also took place happened in Chile. A magnitude-9.5 quake in 1960 killed more than 5,000 people. The most recent large quake in February 2010 hit central and southern Chile with a magnitude of 8.8, followed by a tsunami that left more than 500 dead with $30 billion in damage to property.

Tsunami waves travel about 800 km per hour, (500 miles per hour). That seems fast, but compared to a seismic wave it is slow. The speed of seismic wave, the P wave (or primary wave, which is the fastest kind of seismic wave) is about 8 km per second, or 30,000 km per hour.

You can compare a tsuanmi wave to the speed of a jet plane.

But while scientists can predict the speed and the direction of tsunamis fairly well, the height at a given location is can be very hard to predict, according to Anne Sheehan from the University of Colorado at Boulder, who spoke to Universe Today for a previous article about the science behind a tsunami.

“For predicting an ensuing tsunami, to have data on the earthquake itself — getting its epicenter located and knowing its size as accurately as possible plays a big role,” she said, “and the USGS plays a big role in getting that information out as quickly as possible.

Update: Here’s an animation from NOAA of the prediction of the tsunami following the April 1 quake in Chile: