2021年苏拉威西岛地震

A moment magnitude (Mw) 6.2 earthquake struck Majene Regency in West Sulawesi, Indonesia, on 15 January 2021, at 02:28 WITA (18:28 UTC). The reverse faulting shock initiated at 18.0 km (11.2 mi) depth with an epicenter inland, located 32 km (20 mi) south of Mamuju. It was preceded by a Mw 5.7 foreshock several hours prior. Shaking from the mainshock was assigned a maximum Modified Mercalli intensity of VI (Strong) in Majene and Mamuju. Four of the five regencies in West Sulawesi were affected. More than 6,000 structures were damaged or destroyed; damage was estimated at Rp829.1 billion rupiah.

At least 105 people were confirmed dead; nearly 6,500 were injured and thousands were displaced.

Tectonic setting

Sulawesi lies within the complex zone of interaction between the Australian, Pacific, Philippine, and Sunda plates in which many small microplates have developed. The main active structure onshore in the western part of Central Sulawesi is the left-lateral NNW–SSE Palu-Koro strike-slip fault that forms the boundary between the North Sula, and Makassar blocks and was responsible for the destructive Palu earthquake in 2018. According to the interpretation of Global Positioning System (GPS) data, the Makassar block is currently rotating anticlockwise, with its northwestern margin showing convergence with the Sunda block across the Makassar Strait.……

Earthquake

The earthquake struck at a shallow depth of 18 km (11 mi) with its epicenter located in Majene Regency, West Sulawesi. The Indonesian Meteorology, Climatology and Geophysics Agency (BMKG) stated that VI (Strong) on the Mercalli intensity scale was felt in Majene for 5–7 seconds. The shaking was felt in neighboring cities, as far away as Makassar to the south and Palu to the north.

Geology

Two thrust faults lie in close proximity to the earthquake epicenter. The offshore Makassar Strait Central Fault and the Mamuju–Majene Thrust Fault.……

Foreshock

Approximately 12 hours, a magnitude 5.7 earthquake struck immediately northwest of the mainshock, triggering multiple landslides and destroying two houses in Majene.……

Damage

Severe damage was reported across Majene Regency and in several areas of Mamuju Regency. West Sulawesi's Gubernatorial Building, located in Mamuju, was destroyed. Two people were trapped beneath the ruins. Parts of Hotel Maleo in Mamuju also reportedly collapsed. Meanwhile, a section of Mirta Manakarra Hospital, a main hospital in Majene also collapsed, trapping at least 6 people inside. Mamuju's main hospital also reportedly suffered extensive damage, with 50% of its structure damaged. Hundreds of patients had to be treated outside of the hospital due to fear of collapse.

Casualties

Dozens of people were buried under debris, most of whom were inside their homes. The earthquake struck at night, when most people were asleep. Four bodies were found in the immediate aftermath. More than 2,000 people where then evacuated to evacuation centers and to Majene's Stadium and Mamuju's Governor's Office. Thirty-eight additional bodies were found by search and rescue personnel later in the day. Most of the victims were residents from the provincial capital, Mamuju and some in Majene. Two people were killed at section of Mamuju's Mitra Manakarra Hospital after it collapsed.

Response

Central government

The President of Indonesia Joko Widodo ordered Minister of Social Affairs Tri Rismaharini to visit the disaster area to supervise the aid distribution in the area. He later sent condolences to the relatives of the victims and hoped for a quick recovery for the survivors and those who were affected. A state of emergency was declared in West Sulawesi. President Joko Widodo later visited the affected areas and promised that the Central Government will provide more help for the regional government of West Sulawesi for the relief effort. Tri Rismaharini stated that aid and logistics will be brought from Makassar.……