Oman could be susceptible to tsunami earthquakes: Study

April 29, 2017

Oman could be susceptible to tsunami earthquakes as powerful as the ones that hit Sumatra  (Indonesia) in 2004 and Fukushima (Japan) in 2011, a new study suggests. The study was conducted on Makran, an area on the southern coast of Iran and Pakistan. 

The study was subsequently published by Geophysical Journal International. Makran is classified as a subduction zone, in which two tectonic plates overlap. In these giant faults called ‘megathrusts’, the plates can get stuck when moving past one another. If the stress is high enough, it can result in magnitude 9 earthquakes.

“Rapid urbanisation along the Omani and Pakistani coasts in recent years has increased the population exposed to earthquakes and tsunamis in the Makran,” one of the study’s authors, Camilla Penney, wrote in an article. “Much of Muscat...is less than ten metres above sea level, making it vulnerable to tsunamis.”

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The eastern side of Makran is already known to produce earthquakes. According to Camilla, the eastern part of Makran already caused an earthquake in 1945, resulting in a tsunami leading to the deaths of 300 people in Pakistan and Oman. Lesser earthquakes have also occurred on the faultline, including February 6 this year. But, the study focuses on the western side of the Makran plate. Until now, western Makran has never produced a known subduction earthquake. But, it says there is new evidence that the western side of Makran has produced earthquakes in the past. Scientists suggest large boulders along the coast of Oman could have been deposited in tsunamis.

“The locations of these boulders suggest that the tsunami which brought them there would need to have come from a subduction earthquake, either in western Makran or along the entire subduction zone - including Pakistan,” wrote Camilla. The scientists also used evidence from studies of the coast of Iran. The authors, which include officials from the National Cartographic Centre in Iran, have installed GPS stations to monitor how fast parts of Iran are moving compared to Arabia. “We found that the velocities fit with Iran being shortened near the coast, suggesting that stress is indeed building up and meaning there could be a large subduction earthquake in the future,” said Camilla.

So if the evidence proves true, that means an earthquake involving both the east and western sides, called a subduction earthquake. That could produce a tsunami, the study said. “If the western part of the Makran (in Iran) also produces earthquakes - and the whole Makran megathrust were to move in one go – it could produce a magnitude 9 earthquake,” said Camilla.

Issa el Hussain, director of the SQU Earthquake Monitoring Centre said the study could be accurate but that more work needs to be done. “The article seems balanced but the research is in its early stage for west Makran to draw such conclusions,” he said. Camilla said she hoped more work and research would be done on the topic. “To help protect these people, and make sure that they are properly prepared, we need to understand this hazard better,” she said. “I hope that in the future we will have a much better idea of what to expect from this subduction zone.”