Expert Talks About The Potential Of M 8.9 Earthquake If A Mentawai Megathrust Occurs

ILLUSTRATION / BMKG

JAKARTA - The Regional Disaster Management Agency (BPBD) of West Sumatra Province (West Sumatra) disclosed the opinion of experts regarding the potential for an earthquake of 8.9 magnitude if the Mentawai Megathrust fault occurred.

"20 to 30 minutes later followed by a tsunami wave in the city of Padang as high as six to 10 meters with a distance of two to five kilometers," said Head of Division (Head) PK BPBD West Sumatra Province Syahrazad Jamil quoted by Antara, Friday, November 13.

The natural disaster is predicted to affect at least 1.3 million people. Using the worst-case scenario, an estimated 39,321 people died, 52,367 were missing and 103,225 were injured.

"Teluk Bayur Port and Minangkabau Airport were destroyed, that's the prediction of the experts," he said.

The island of Sumatra has experienced several tsunamis. Especially in West Sumatra, the tsunami occurred in the Mentawai Islands on October 25, 2010 and claimed up to 408 people.

In order to be aware of the worst possibility, the province of West Sumatra has made various efforts, including building partnerships and coordination with national and international non-governmental organizations (NGOs) including non-governmental organizations (NGOs).

The West Sumatra government, he continued, is also working together in the formation of the Disaster Risk Reduction Forum (FPRB) and disaster preparedness groups up to the village or sub-district level.

Furthermore, cooperation with the TNI and Polri will continue to be strengthened in terms of disaster management, including with state and private universities in the province.

Not only that, disaster risk reduction programs and activities will also continue to be strengthened by establishing disaster-safe education units, disaster preparedness groups, independent evacuation drills and the construction of mitigation and evacuation facilities in the form of shelters, evacuation route maps, and early warning.

"The shelter assistance that we build provides a sense of security for the community. Moreover, since the 2009 earthquake, buildings such as hotels have mushroomed," said Syahrazad.

What is a Megathrust Earthquake?

BMKG Head of Earthquake and Tsunami Mitigation Division, Daryono, explained that the megathrust zone is actually just a term to describe the source of the earthquake collision of plates at shallow depths.

In this case, the oceanic plates that are submerged beneath the continental plates form a stress field in the contact areas between the plates which can then suddenly shift triggering earthquakes. If an earthquake occurs, the part of the continental plate that is above the oceanic plate moves pushed up (thrusting).

Daryono explained, the plate subduction pathways are generally very long with shallow depths covering the contact areas between the plates. During its development, the subduction zone was assumed to be a "large upward fault", which is now popularly known as the megathrust zone.

“The megathrust zone is nothing new. In Indonesia, the earthquake source zone has existed for millions of years when the Indonesian archipelago was formed, "said Daryono.

The megathrust zone is in an active subduction zone, such as: (1) Sunda Subduction covering Sumatra, Java, Bali, Lombok and Sumba, (2) Banda Subduction, (3) Maluku Sea Plate Subduction, (4) Sulawesi Subduction, (5) Subduction of the Philippine Sea Plate, and (6) subduction of Northern Papua.

Currently, Indonesia's megathrust zone segment has recognized its potential. All earthquake activity that originates in the megathrust zone is called a megathrust earthquake and is not always of a large magnitude.

"As a source of earthquakes, the megathrust zone can generate earthquakes of various magnitudes and depths. Data from BMKG monitoring shows that small earthquakes occur more frequently in the megathrust zone, although the megathrust zone can trigger large earthquakes, "said Daryono.