Turkey Quake Dwarfs 1995 Hanshin Tremor in Released Energy

The Yomiuri Shimbun

21:00 JST, February 14, 2023

The amount of energy released by the 7.8-magnitude earthquake that struck southern Turkey and northwestern Syria was more than 20 times larger than that of the 1995 Great Hanshin Earthquake, making it one of the largest inland quakes in recorded history, according to research institutes.

A week after the earthquake, which was followed by a 7.5-magnitude aftershock, the death toll had exceeded 35,000. The quake is already the sixth-worst worldwide in the 21st century in terms of dead and missing persons.

According to the U.S. Geological Survey, the aftershock occurred about nine hours after the main temblor.

Tohoku University and other institutes estimated that the energy released by the mainshock was about 22 times larger than that of the Hanshin quake. When the energy is converted using the Japanese seismic intensity scale set by the Japan Meteorological Agency, part of the affected area was found to have experienced a tremor tantamount to the scale’s highest rating of 7, they said.

The earthquake was triggered by a large slip along an underlying fault. According to an analysis by the Geospatial Information Authority of Japan based on data from the Japan Aerospace Exploration Agency’s Earth-observation satellite Daichi-2, the horizontal slip along the fault was up to four meters, about four times larger than in the Hanshin quake.

The massive damage incurred is also believed to have been due in part to large population centers being struck.

Akira Wada, a professor emeritus of quake-resistant architecture at the Tokyo Institute of Technology, analyzed images of Antakya, a city in southern Turkey, taken by a Maxar Technologies Inc. satellite before and after the tremor.

He found that one area in which many five-story apartment buildings toppled onto their sides was developed with little space between the buildings, and that some were possibly taken down by the collapse of a neighboring block.

According to the Handbook of Scientific Tables, an earthquake in Haiti in 2010 had the highest toll of dead and missing in the 21st century at 316,000, followed by the 2004 Sumatra-Andaman quake at 227,898, the 2005 Pakistan quake with at least 86,000, the 2008 Sichuan quake at 69,227 and the 2003 Bam quake in Iran at 43,200.