BMKG Analysis Of The Largest M 6.9 Earthquake In Morocco's History

PHOTO OF ILLUSTRATION/UNSPLASH/JEN'S AB

JAKARTA - The Meteorology, Climatology and Geophysics Agency (BMKG) explained that the analysis of the 6.9 magnitude (M) earthquake in Morocco was the largest in the country's history.

Head of the BMKG Earthquake and Tsunami Center, Daryono, said the earthquake was a shallow crustal earthquake due to active fault activity in the Atlas Mountains Zone, Morocco.

The epicenter of this earthquake is located at coordinates 31.01 degrees north latitude and 8.46 degrees west longitude, precisely on land with a very shallow hypocenter depth, which is 28 kilometers.

"This Mw6.9 magnitude earthquake is the main earthquake (mainshock) and the largest in historical records ever occurred in Morocco. Recent reports show that the earthquake caused damage with the death toll," Daryono said as quoted by ANTARA, Saturday, September 9.

Taking into account the location of the epicenter and the depth of the hypocenter, the earthquake that occurred was a type of shallow crustal earthquake due to active fault activity in the Atlas Mountains Zone, Morocco. The morphology of this mountainous route is directed by Baratdaya -Northeast, from Agadir to Agatat Ahmadou Haddou, Morocco," he continued.

The results of the analysis of the source mechanism carried out by the BMKG show that the earthquake that occurred had a thrust fault mechanism, which reflected a compressed force that occurred in the tectonic zone of the earthquake source.

"This earthquake occurred in the area of the source of the active fault earthquake that had been mapped, however, this zone is known for its relatively low seismic history," said Daryono.

The earthquake had a devastating impact on the VII - IX MMI intensity scale, causing damage and death toll in the Old Town of Marrakesh, which is the fourth largest city in Morocco, one of the largest population centers.

Marrakesh suffered the most severe damage because it was close to the source of the earthquake coupled with the existence of old buildings that were prone to collapse due to earthquake shocks due to weak structural conditions.

Major cities affected by the earthquake shocks are quite strong around Marrakesh, namely Ourazate, Essaouira, Safi, Agadir, Casablanca and Errachia. Not only in Morocco, this shallow crust earthquake was felt in a very large area, including neighboring countries, such as Portugal, Spain and Algeria.

The Mw6.9 earthquake, which claimed lives, reminded us of the devastating earthquake that rocked Agadir Morocco with a magnitude of Mw5.8 on February 29, 1960. Although the magnitude of the earthquake was relatively small, the earthquake damaged Agadir killed more than 10,000 people, and became the deadliest earthquake in Morocco's history.

"The current Marrakesh Mw6.9 earthquake based on its magnitude is comparable to the historic destructive earthquake that destroyed the city of Meknes with a magnitude of Mw6.5-7.0 that occurred on November 27, 1755," said Daryono.

This earthquake killed thousands of people, as it hit mountainous areas with many distributions of rural settlements and small towns that had many vulnerable buildings with weak structures. In addition, this strong earthquake occurred at night at 23.00 local time, while all residents were staying at home.

As of 16.25 WIB this afternoon, monitoring results showed that there had been several aftershocks with one significant aftershock with M4.9 magnitude at 05.30 WIB which was felt on the MMI VI intensity scale.