Geology And Geophysics

Deadly Earthquakes

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"Deadly Earthquakes"
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The earth shaking and quaking is not the concern. These are some 8000 earthquakes each year. Eight Of these are major quakes. Yet is is only the earthquakes that cause death that capture the headlines. The actual killer is the events that earthquakes set off. The earthquake's henchmen are the tsunamis, fires, fissures, and eruptions that are created.

Earthquakes are shifts in the tectonic plates that slide on the earth's outer crust. Faults are where these tectonic plates meet, such as, the San Andreas Fault. When the plates move, the earth above them shake and quake. Earthquakes, like most natural disasters, cause few deaths directly. The secondary events cause the greatest number of deaths. Buildings collapse, fissures open, fires break out and tsunamis can happen. The rim around the Pacific ocean produces the greatest number of earthquakes each year. However, where ever a fault line is found, earthquakes are a concern. A fault line in central United States, usually not associated with earthquakes, produced the strongest earthquake in the lower 48 states.

The greatest number of deaths associated with an earthquake occurred in China in 1556. Almost a million people were killed. This was the deadliest earthquake but not the strongest. The 1960 Chilean quake measured a magnitude 9.5. The 1556 Shaanxi earthquake is estimated to have been a magnitude 8.0. There were just over 2000 deaths recorded from the Chile earthquake including the tsunami deaths in other shoreline locations. The New Madrid Earthquake, strongest earthquake in the US, took so few lives that it was never recorded. The difference lies in the human population and development in the area affected. Large populations concentrated in high risk areas usually will result in large deadly disasters.

The Tangshan, China of 1976 had a magnitude of 7.5 but accounted for the loss of half million or more people. China is known for disastrous earthquakes due to the concentration of people in areas that are known fault lines. The Indian Ocean earthquake with a magnitude of 9.3 caused a massive tsunami that took over 200,000 lives. The total deaths attributed to this earthquake reached nearer to 250,000 lives. The loss of life that occurs due to illness and exposure from homelessness is not recorded.

The deadliest earthquakes are often associated with other natural disasters. The Gansu, China earthquake of 1920 caused massive landslides that took nearly a quarter million lives. The Japanese Kanto earthquake of 1923 caused fires that swept through Tokyo. The loss of life due to fire in Japan amounted to 150,000 lives.

The horrors of earthquakes are not only unavoidable but unpredictable. Recent attempts to forecast earthquakes have failed. Massive loss of life in populated areas are the risk that is present in fault line areas. Building reinforcement and other precautions help prevent building collapse and reduce loss of life. The fissures, tsunamis, landslides and fires that spring from earthquakes are beyond human control.

More about this author: Fran Moriarty

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