As a powerful 7.4-magnitude earthquake struck western Colombia, resulting in more than 100 deaths, attention is focusing on the geological characteristics of the region, which is part of the Pacific Ring of Fire.

According to the Euro-Mediterranean Seismological Centre (EMSC), the earthquake occurred at around 7:34 a.m. local time on the 10th, registering a magnitude of 7.4.

The epicenter, directly above the point where the earthquake originated, is located in the Choco Department along the western coast of Colombia.

This region is part of the Ring of Fire, the circum-Pacific seismic belt known to concentrate about 90 percent of the world's earthquakes and volcanic activity.

Geological experts note that western Colombia is where the Nazca Plate, an oceanic plate at the bottom of the Pacific Ocean, meets the South American Plate, a continental plate.

In this region, the Nazca Plate at the bottom of the Pacific is being pushed beneath the South American continental plate.

The phenomenon where one tectonic plate dives beneath another is called subduction.

When strong friction occurs while two plates are locked together, their movement stops and a tremendous amount of energy builds up in between.

Then, when the frictional force fails to hold, the plates suddenly move and the accumulated energy propagates as seismic waves.

In the past, mega-earthquakes such as the 2011 Great East Japan Earthquake and the 1960 Great Chilean Earthquake frequently occurred in regions where such subduction takes place.

The Ring of Fire, stretching from East Asia to North and South America and South Asia, can also be viewed as a massive seismic and volcanic activity belt connecting subduction zones of various oceanic and continental plates.

Just like the Nazca Plate and the South American Plate in the South American section that triggered this strong Colombian earthquake, seismic energy continues to accumulate in other regions forming the Ring of Fire.

In Japan and the Kuril Islands, the Pacific Plate, Eurasian Plate, and North American Plate are interlocking, while the Pacific Plate and North American Plate interlock in Alaska and the Aleutian Islands.

In western North America, the Juan de Fuca Plate and the North American Plate are locked together, and in Southeast Asia, including the Philippines, the Pacific Plate, Philippine Sea Plate, and Eurasian Plate are complexly intertwined.

The strong earthquake in Kumamoto, Japan, which occurred on the 28th of last month and caused dozens of casualties, was also an earthquake that occurred in the Ring of Fire.

However, regions with a high risk of strong earthquakes that are not subduction zones, such as California in the United States, are also part of the Ring of Fire.

The epicenter of this Colombian earthquake was relatively deep, at about 110 kilometers.

Generally, earthquakes with deeper hypocenters tend to deliver less impact to facilities on the ground surface than shallow earthquakes.

However, as this earthquake was powerful enough to reach a magnitude of 7.4, it was observed to have left severe damage.

Suzan van der Lee, a seismologist at Northwestern University in the U.S., analyzed that although the earthquake had a deep hypocenter, its sheer magnitude caused significant adverse effects.

Van der Lee explained to Reuters that in this earthquake, rather than the underground fault moving up and down, a phenomenon also appeared where both sides moved horizontally, sliding past each other.

She analyzed that this may have magnified the damage in valley areas where many people live.

Earthquakes in the magnitude 7 range release an enormous amount of energy all at once.

Among experts, there are estimates that a strong earthquake in the magnitude 7 range can unleash power equivalent to hundreds of atomic bombs dropped on Hiroshima, Japan, in the past.

Recently in South America, a 7.5-magnitude strong earthquake also occurred on June 24 in Venezuela, a neighboring country of Colombia.

However, the geological environments in which the earthquakes in Colombia and Venezuela occurred are different.

Venezuela does not belong to the Ring of Fire, and the earthquake at that time was a relatively shallow one that occurred successively at underground depths of 20 kilometers and 10 kilometers.

With the death toll from this earthquake confirmed to have exceeded 100 so far, the scale of damage is expected to increase further as rescue and search operations continue.
 
(Photo: AP, Yonhap News)