
A
Mw 6.4 earthquake struck the island of
Lombok
Lombok, is an island in West Nusa Tenggara province, Indonesia. It forms part of the chain of the Lesser Sunda Islands, with the Lombok Strait separating it from Bali to the west and the Alas Strait between it and Sumbawa to the east. It is rou ...
on the morning of 29 July 2018 at a shallow depth of . Widespread damage was reported in the area, and authorities confirmed that 20 people were killed in the earthquake while hundreds were injured.
The
epicentre
The epicenter (), epicentre, or epicentrum in seismology is the point on the Earth's surface directly above a hypocenter or focus, the point where an earthquake or an underground explosion originates.
Determination
The primary purpose of a s ...
was located in Sembalun Subdistrict,
East Lombok Regency
East Lombok Regency is a regency () of the Indonesian Province of West Nusa Tenggara. It is located on the island of Lombok, of which it comprises the eastern third (including minor offshore islands); the administrative capital is the town of Sel ...
. The earthquake was a
foreshock
A foreshock is an earthquake that occurs before a larger seismic eventthe mainshockand is related to it in both time and space. The designation of an earthquake as ''foreshock'', ''mainshock'' or aftershock is only possible after the full sequenc ...
to the larger 6.9 earthquake
which struck the island a week later.
Tectonic setting
Lombok lies on the
destructive plate boundary between the
Australian plate
The Australian plate is or was a major tectonic plate in the eastern and, largely, southern hemispheres. Originally a part of the ancient continent of Gondwana, Australia remained connected to India and Antarctica until approximately when Indi ...
and the
Sunda plate. To the east of
Bali
Bali (English:; Balinese language, Balinese: ) is a Provinces of Indonesia, province of Indonesia and the westernmost of the Lesser Sunda Islands. East of Java and west of Lombok, the province includes the island of Bali and a few smaller o ...
the plate boundary starts to involve a collision between the leading edge of the Australian
continent
A continent is any of several large geographical regions. Continents are generally identified by convention (norm), convention rather than any strict criteria. A continent could be a single large landmass, a part of a very large landmass, as ...
and the eastern part of the
Sunda Arc and the western end of the
Banda Arc. In response to this collision, the arc itself has begun to be pushed over the
back-arc
The back-arc region is the area behind a volcanic arc. In island arc, island volcanic arcs, it consists of back-arc basins of oceanic crust with abyssal zone, abyssal depths, which may be separated by remnant arcs, similar to island arcs. In conti ...
Bali Basin along a major
thrust fault
A thrust fault is a break in the Earth's crust, across which older rocks are pushed above younger rocks.
Thrust geometry and nomenclature
Reverse faults
A thrust fault is a type of reverse fault that has a dip of 45 degrees or less.
I ...
, the long
Flores Thrust. The Lombok earthquake has been attributed to movement along the Flores Thrust.
[
]
Earthquake
The earthquake struck on Sunday, at 06:47 local time, at a shallow depth of . Residents reported severe shaking near the epicentre, with multiple structures reportedly collapsing. Dozens of houses were destroyed and widespread damage was reported. The shaking lasted 10–20 seconds. Local residents have said it was the strongest quake to have ever hit Lombok. The earthquake was felt as far away as Denpasar
Denpasar (; Balinese script, Balinese: ᬤᬾᬦ᭄ᬧᬲᬃ, ''Dénpasar'') is the capital city of the province of Bali, Indonesia.
Denpasar is the largest city in the Lesser Sunda Islands and the second largest city in Eastern Indonesia after ...
, Bali
Bali (English:; Balinese language, Balinese: ) is a Provinces of Indonesia, province of Indonesia and the westernmost of the Lesser Sunda Islands. East of Java and west of Lombok, the province includes the island of Bali and a few smaller o ...
. In Karangasem Regency
Karangasem Regency (Indonesian language, Indonesian: ''Kabupaten Karangasem''; Balinese language, Balinese: ᬓᬪᬹᬧᬢᬾᬦ᭄ᬓᬭᬗᬲᭂᬫ᭄) is a Regency (Indonesia), regency (''kabupaten'') of the province of Bali, Indonesia. It c ...
, Bali, a temple collapsed and a local court was damaged.
Landslides struck the north portion of Mount Rinjani
Mount Rinjani ( Sasak: ''Gunong Rinjani'', ) is an active volcano in Indonesia on the island of Lombok. Administratively the mountain is in the Regency of North Lombok, West Nusa Tenggara ( Indonesian: ''Nusa Tenggara Barat'', NTB). It rises t ...
, where routes popular with hiking tourists are located. Authorities confirmed that 826 hikers were trapped on the mountain and waited to be rescued.
In Selong, the capital of East Lombok Regency
East Lombok Regency is a regency () of the Indonesian Province of West Nusa Tenggara. It is located on the island of Lombok, of which it comprises the eastern third (including minor offshore islands); the administrative capital is the town of Sel ...
, dozens of patients were evacuated from dr. Soedjono regional hospital while in Sembalun a Community Health Centre was significantly damaged.
Authorities confirmed that 276 moderate aftershocks from 5.0 to 5.5 } were recorded by the Indonesian Agency for Meteorology, Climatology and Geophysics (BMKG). The largest aftershock at a magnitude 5.7 } recorded at 10:16 local time. On 3 August, officials confirmed that more than 500 aftershocks had been recorded.
Casualties
Authorities confirmed that a Malaysian tourist was killed by a falling wall. The Indonesian National Board for Disaster Management (BNPB) confirmed that 10 people were killed and 40 people were injured. The government confirmed that 18 Malaysians were affected by the earthquake.
On the evening of 29 July, officials announced that the number of people who had been killed by the earthquake had risen to 16. Later the number rose to 17, then 20 on 5 August.
Aftermath
In the aftermath of the earthquake, blackouts occurred throughout Lombok and telecommunications went down. The National Electricity Company (PLN) stated that they would temporarily cut the electricity in East Lombok Regency for examination. They later announced that normal operation would resume within hours.
The government immediately closed the Mount Rinjani National Park. Hiking and other activities were banned in the area due to fear of landslides. Indonesian President Joko Widodo
Joko Widodo (; born 21 June 1961), often known mononymously as Jokowi, is an Indonesian politician, engineer, and businessman who served as the seventh president of Indonesia from 2014 to 2024. Previously a member of the Indonesian Democratic ...
, who had planned to visit West Nusa Tenggara prior to the earthquake, ordered Muhammad Zainul Majdi, the Governor of West Nusa Tenggara
West Nusa Tenggara ( – NTB) is a provinces of Indonesia, province of Indonesia. It comprises the western portion of the Lesser Sunda Islands, with the exception of Bali which is its own province. The area of this province is which consists of ...
to immediately deploy search and rescue personnel to the affected areas.
Authorities stated on 29 July 2018, that East Lombok Regency had suffered the most damage. Sembalun District and Sambelia District were regarded as the worst affected areas in the regency. Hundreds of tents were set up while dozens of search and rescue personnel, including members from the Indonesian Armed Forces, police and other government institutions, were deployed onto the declared disaster zone.
On 29 July 2018, Bali Red Cross announced that they would send medical experts and volunteers to Lombok.
Indonesian Social Minister Idrus Marham confirmed that the government would send multiple aids to the victims.
On 30 July, Joko Widodo
Joko Widodo (; born 21 June 1961), often known mononymously as Jokowi, is an Indonesian politician, engineer, and businessman who served as the seventh president of Indonesia from 2014 to 2024. Previously a member of the Indonesian Democratic ...
, the Indonesian President, Muhammad Zainul Majdi the Governor of West Nusa Tenggara, and Idrus Marham, the Social Minister visited survivors and victims of the earthquake and sent condolences to the affected families. Majdi declared a state emergency for three days. They distributed books and other supplies to survivors and later examined the damage. Joko Widodo later announced that the government would help the victims rebuild their houses and infrastructures in Lombok. On 31 July he stated that the government would immediately provide compensation of at least 50 million rupiah for each damaged or destroyed building. The renovation of the damaged buildings would be assisted by the Indonesian National Armed Forces
The Indonesian National Armed Forces (; abbreviated as TNI) are the military forces of the Republic of Indonesia. It consists of the Indonesian Army, Army (''TNI-AD''), Indonesian Navy, Navy (''TNI-AL''), and Indonesian Air Force, Air Force ('' ...
.
Spokesman of the BNPB, Sutopo Purwo Nugroho, stated that more than 1,000 structures across Lombok were either damaged or destroyed. BMKG advised people not to enter their homes as more aftershocks are expected in the following days.
The Malaysian government through their Prime Minister Mahathir Mohamad
Mahathir bin Mohamad (; ; born 10 July 1925) is a Malaysian politician, author and doctor who was respectively the fourth and seventh Prime Minister of Malaysia, prime minister of Malaysia from 1981 to 2003 and from 2018 to 2020. He was the ...
have announced that aid would be sent to the Indonesian people who were affected by the earthquake, with Mercy Malaysia also began to distribute essential relief items for the victims. The Malaysian Global Peace Mission (GPM) deployed a team to identify the urgent needs of victims, with an initial RM10,000 aid, and an additional RM50,000 brought the following week by a second aid team.
On 5 August 2018 a Mw 6.9 or 7.0 earthquake struck Lombok, prompting tsunami warnings.
Search and rescue
The Indonesian National Search and Rescue Agency (SAR) announced that there were two main locations where trapped hikers were located. The first one was in Segara Anak Lake while the second one was at the basecamp. As of 30 July more than 700 hikers were on the mountain, of whom 100 were from Thailand
Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...
, the United States, and other countries. SAR stated that they had prepared two helicopters for the evacuation process and that at least 500 hikers had been evacuated from the mountain.
There were confusions among officials on the number of hikers on the mountain, as it was reported that most hikers were not registered by their tour guides. Several media stated that around 600 hikers were on the mountain, while another stated that there were around 500 people. Officials later finalized the total number to more than 1,200 hikers of whom around 700 of them were foreigners from 26 countries, the majority are Thais. Government officials stated that around 300 Thais were on the mountain during the disaster.
On 1 August, all 1,226 hikers had been rescued from the mountain.
References
External links
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{{DEFAULTSORT:2018 Lombok earthquake, July
2018 disasters in Indonesia
2018 earthquakes
Earthquakes in Indonesia
July 2018 in Indonesia
West Nusa Tenggara
Landslides in Indonesia