Experts Say South Nias Earthquake Was Predictable 200 Years Ago

PADANG - Andalas University (Unand) earthquake expert Dr. Badrul Mustafa Kemal said the earthquake that occurred in South Nias was a subduction of the Siberut segment which intersects with the Mentawai megathrust segment. which has accumulated for more than 200 years since 1797 in that segment," he said in Padang, Monday, March 13. According to him, whether the earthquake was the opening for a bigger earthquake, no one knows. predict it. It is possible that the energy accumulated in the empty zone of the Siberut segment is released with a moderate strength of 6.0 to 7.0 magnitude over the past 10 to 20 years. "We must continue to practice facing the very strong earthquake in the Mentawai megathrust, as well as facing the possibility of a tsunami," he said.

He hopes that the government and disaster risk reduction activists will again prepare the community for this. Badrul explained that on the island of Sumatra, there was a movement of the Indo-Australian plate crashing and subducting under the Eurasian plate resulting in a series of fore-island arcs or non-volcanic accretionary prismatic zones, including Nias and Mentawai Islands. This subduction then produces the potential for a strong and very strong earthquake. On land it also produces potential tectonic earthquakes, including the Talamau earthquake in Pasaman which just occurred with a magnitude of M6.1 on February 25, 2022. The subduction that produces the Mentawai megathrust is divided into two segments, namely the Siberut and Sipora-Pagai segments. Both of these segments have the potential for a very strong earthquake with a return period of about 200-300 years. The Sipora-Pagai segment has experienced a return period after 1833, with a series of earthquakes on September 12, 2007 (M8.4), September 13, 2007 (M7.9 and 7.2), and October 25, 2010 (M7.4). The last one on October 25, 2010 caused a tsunami, because the conditions for its occurrence were met, namely that the epicenter was exactly on the rising fault, southwest of South Pagai.