Soil Liquefaction and Weak Buildings Exacerbated Venezuela Earthquake Damage

[Anchor]

The massive scale of the damage from the recent earthquake in Venezuela is not solely due to the double shock of back-to-back tremors just 39 seconds apart and the shallow focal depth of only 10 to 20 kilometers. The areas that suffered the most, including the capital city of Caracas, are located on soft sedimentary basins. These geological factors amplified the destruction. Another major issue was the prevalence of non-ductile concrete buildings constructed before the 1970s, which are highly vulnerable to seismic shocks.

Reporter Park Won-gyeong explains in detail how these factors worsened the damage.

[Reporter]

The areas that sustained the most significant damage from this earthquake are the coastal city of La Guaira and the Altamira district, which is adjacent to mountains north of the capital, Caracas.

Both locations are approximately 160 kilometers away from the epicenter.

The reason these two areas suffered more damage than locations closer to the epicenter is attributed to the characteristics of the soil, known as alluvial soil.

Alluvial soil is formed by the accumulation of silt or sand and is typically found near rivers, coastlines, or mountains.

Under normal conditions, sand grains are tightly bound together. However, when subjected to seismic vibrations, these bonds break, and water seeps between the grains, causing the entire soil mass to soften—a phenomenon known as soil liquefaction. This is cited as a key reason for the amplified damage.

[Kim Ki-bum / Professor of Geological and Environmental Sciences at Pusan National University: When soil liquefaction occurs, the ground that felt solid turns into something like soup or porridge. If a building is constructed on such ground, it is inevitable that the structure will collapse because the foundation has essentially turned into liquid.]

It has been confirmed that there are no casualties among the approximately 120 Korean expatriates in the region. There is speculation that this is because the areas where many of them reside have more solid ground.

The high number of non-ductile concrete buildings constructed before the 1970s is also identified as a cause for the increased damage.

Because these buildings contain insufficient steel reinforcement, they do not bend when an earthquake strikes; instead, they crumble downward, collapsing in layers.

[William Yeck / Geophysicist at the U.S. Geological Survey: It is not the shaking that kills people; it is the buildings. And it is precisely the collapse of those buildings that leads to tragic loss of life.]

In particular, this pancake-style collapse leaves almost no survival space for people inside the buildings and makes rescue operations extremely difficult.

Reported by Park Won-gyeong | Video by Kim Do-kyun, Han Seung-ho | XR by Lee Jun-ho, Choi Jae-young | Video Editing by So Ji-hye
※ Please note: This article was translated by AI and may contain errors.