The Indonesian island of Sumatra is located in a highly seismic area of the world. In addition to the subduction zone off the west coast of the island, Sumatra also has a large strike-slip fault, the Great Sumatran Fault also known as Semangko Fault, running the entire length of the island. This fault zone accommodates most of the strike-slip motion associated with the oblique convergence between the Indo-Australian and Eurasian plates. The fault ends in the north just below the city of Banda Aceh, which was devastated in the 2004 Indian Ocean earthquake. After the December 2004 earthquake, pressure on the Great Sumatran Fault has increased tremendously, especially in the north.
The 1979 Bali earthquake occurred at with a surface wave magnitude of 6.3. The shock occurred southeast of the coast of Karangasem Regency in the Lombok Strait, and about 60 kilometres (37 mi) east-northeast of Denpasar. Up to 80 percent of the buildings in Karangasem Regency were damaged, between 15,000 and 500,000 people were displaced, and road links to the provincial capital of Denpasar were briefly severed.
The 1976 Bali earthquake occurred at with a surface wave magnitude of 6.5. The shock occurred 5 kilometres (3.1 mi) south of the Bali Sea coast of the Buleleng Regency, and about 65 kilometres (40 mi) northwest of Denpasar. Up to ninety percent of houses in Buleleng Regency were seriously damaged or destroyed and the Seririt sub-district was almost completely destroyed, where a school building collapsed and trapped at least 200 students. 573 people are believed to have died; at least 544 in Buleleng Regency, 24 in Jembrana and 5 in Tabanan. Four thousand more suffered injuries and an estimated 450,000 were left temporarily homeless.
A Mw 6.4 earthquake struck the island of Lombok on the morning of 29 July 2018 at a shallow depth of 14 km (8.7 mi). Widespread damage was reported in the area, and authorities confirmed that 20 people were killed in the earthquake while hundreds were injured.
On 5 August 2018, a destructive and shallow earthquake measuring Mw 6.9 struck the island of Lombok, Indonesia. It was the main shock following its foreshock, a nearby Mw 6.4 earthquake on 29 July. It was followed by a nearby 6.9 earthquake on 19 August 2018.
On 19 August 2018 a major earthquake struck with high intensity on the northeast corner of Lombok and northwest Sumbawa at 22:56 local time, a few km to the east of the series of quakes that had been rocking the area for the past 3 weeks. It was measured at Mw 6.9 (USGS), at a depth of 25.6 km. The Indonesian BMKG announced that it was a new major earthquake and it was not an aftershock. The earthquake occurred on the same overall structure, the Flores Back Arc Thrust Fault, however according to scientists it happened on a different thrust fault as there are many individual structures within the belt. There were 14 deaths and 1800 homes have been damaged, half severely, due to this event, including deaths on Sumbawa, following 2 deaths from the previous Lombok quake roughly 24 hours earlier. Heavy tiles fell from the local mosque, and 143 patients were being treated outdoors in makeshift tents for injuries on Sumbawa.
Flores Back Arc Thrust Fault is a major system of west-east trending thrust faults that extend eastwards from west of Lombok towards the islands of Sumbawa, Flores, and Alor, with a total length of at least 800 km. The thrust faults are south-dipping and lie within the back arc region of the Sunda-Banda Arc, which is related to the ongoing subduction of the Australian Plate beneath the Sunda and Banda Sea Plates. The thrust fault system developed as a result of the onset of continental collision as continental crust of the Australian Plate reached the Sunda Trench. The eastern part of the fault system is also known as the Wetar thrust. Above the main thrust fault are a series of imbricate (overlapping) thrust faults. These imbricate thrust faults are shallower in depth than the main Flores thrust. Although the exact thrust faults have not been established, these faults were thought to be responsible for the 2018 Lombok earthquakes.
On 11 October 2018, an earthquake struck off the coast of East Java, Indonesia, with the epicentre located off the coast of Situbondo Regency. The earthquake, which struck at dawn, killing four people in addition to destroying or damaging hundreds of houses, mostly on the small island of Sapudi.
On 17 March 2019, an earthquake measuring Mw 5.6 struck the island of Lombok in West Nusa Tenggara, Indonesia. The earthquake triggered a landslide, killing six and injuring nearly 200 others.
The 2019 Sunda Strait earthquake occurred on the night of 2 August 2019, when a magnitude 6.9 earthquake rattled Sunda Strait at a moderate depth of 52.8 kilometres. The epicentre was located 214 km from Bandar Lampung, the capital of Lampung and 147 km west of Sumur, Pandeglang Regency. The earthquake struck with a maximum intensity of VI (Strong). The earthquake prompted a tsunami warning in the area, with authorities urging coastal residents to immediately evacuate to higher grounds.
An earthquake struck Majene Regency in the province of West Sulawesi, on the Indonesian island of Sulawesi on 15 January 2021, at 02:28 WITA, with a moment magnitude of 6.2. This earthquake was felt as far away as Makassar, the capital of South Sulawesi, and Palu in Central Sulawesi. Strong shaking was reported in Majene and the provincial capital Mamuju for at least 5–7 seconds. It was preceded by a foreshock measuring 5.7 magnitude a few hours earlier.
The 1674 Ambon earthquake occurred on February 17 between 19:30 and 20:00 local time in the Maluku Islands. The resulting tsunami reached heights of up to 100 metres (330 ft) on Ambon Island killing over 2,000 individuals. It was the first detailed documentation of a tsunami in Indonesia and the largest ever recorded in the country. The exact fault which produced the earthquake has never been determined, but geologists postulate either a local fault, or a larger thrust fault offshore. The extreme tsunami was likely the result of a submarine landslide.
An earthquake occurred on 10 April 2021 at 14:00 local time (UTC+07:00) off the south coast of eastern Java. The epicenter of the earthquake is located 44 km south southwest of Gondanglegi Kulon in East Java province. Measuring 6.0 or 6.1 on the moment magnitude scale (Mw ) and having a depth of 82.3 km, the earthquake caused moderate shaking measuring V on the Mercalli intensity scale. At least 10 individuals are known to have died from the earthquake and another 104 were seriously injured.
The Lembang Fault is an active fault located 10 km north of the city of Bandung on the Indonesian island of Java. This sinstral slip fault is estimated to measure 29 km in length. While no historical earthquakes have occurred, the fault is thought to be possible of generating a magnitude 6.5 to 7.0 earthquake in the future. Because of the potential for large and damaging earthquakes on the fault, the Meteorology, Climatology and Geophysics Agency (BMKG) has been monitoring activity on the fault.
The 1995 Kerinci earthquake struck near Sungai Penuh in Jambi Province on the island of Sumatra, Indonesia. It earthquake occurred at 01:18 WIB local time on October 7. The earthquake measured 6.7 on the moment magnitude scale, and 6.9–7.0 on the surface wave magnitude scale. Between 84 and possibly even 100 people were killed in the earthquake. An extimated 4,000 buildings collapsed or were seriously damaged while a further 5,000 suffered some damage.
The 1815 Bali earthquake occurred on November 22 between 22:00 and 23:00 local time (WITA), affecting the Bali Kingdom. The estimated moment magnitude 7.0 earthquake struck off the north coast of Bali at a shallow depth. It was assigned a maximum intensity of IX (Violent) on the Mercalli intensity scale, causing severe damage in Buleleng and Tabanan. The earthquake caused a landslide and tsunami that killed 11,453 people.
An earthquake occurred 112 km, offshore, north of Maumere in the Flores Sea on December 14. The quake had a moment magnitude of 7.3 according to the United States Geological Survey (USGS). One person was killed and 97 others suffered injuries.
On 25 February 2022, a magnitude 6.1 earthquake struck West Sumatra, Indonesia. According to the U.S. Geological Survey, the earthquake struck at a depth of 4.9 kilometres (3.0 mi) and had an epicenter in Pasaman. At least 19 people died, 425 were injured, and four others were missing. Severe damage occurred in Tigo Nagari District, Pasaman.
