Tsunami risk identified near future Indonesian capital

Scientists map ancient underwater landslides in the region chosen for Jakarta's replacement.

Scientists have identified a potential tsunami risk in the region chosen by Indonesia for its new capital.

The researchers mapped evidence of multiple ancient underwater landslides in the Makassar Strait between the islands of Borneo and Sulawesi.

If the largest of these were repeated today, it would generate tsunami capable of inundating Balikpapan Bay - an area close to the proposed capital.

But the international team cautions against an overreaction.

"We still have a lot more work to do to properly assess the situation. That said, this is something that Indonesian governments probably should have on the risk register somewhere - even if we're only talking about 'low frequency, high impact' events," said Dr Uisdean Nicholson from Heriot-Watt University, UK. 

His British-Indonesian research team used seismic data to investigate the sediments and their structure on the Makassar seafloor.

The survey revealed 19 distinct zones along the strait where mud, sand and silt have tumbled downslope into deeper waters.

Some of these slides involved hundreds of cubic kilometres of material - volumes that are more than capable of disturbing the water column, and of producing large waves at the sea surface.

"These landslides - or mass transport deposits (MTDs) as we call them - are quite easy to spot in the seismic data," explained Aberdeen University's Dr Rachel Brackenridge, the lead author on the paper describing the research.

"They're lens-shaped and the sediments within them are chaotic; they're not the flat, ordered, tramline-like layers you expect to find. I mapped 19 events, but that's limited by the resolution of the data. There will be other, smaller events I just couldn't see," she told BBC News.

All of the MTDs are on the western side of the deep (3,000m) channel that runs through the Makassar Strait. And they're also predominantly to the south of the outlet delta for Borneo island''s Mahakam River, which is discharging millions of cubic metres of sediment every year.

The team thinks this material is picked up by currents in the strait and then dumped where the shallower parts of the seafloor fall away into the deep.

 

The steep piles of sediment sculpted over time ultimately collapse downslope, triggered perhaps by the shaking from a local earthquake. This is Indonesia after all.

What the team cannot say right now is when the submarine landslides occurred. The researchers' best estimate is within the current geological period - so, within the last 2.6 million years.

Cores extracted from the MTDs could better constrain their age and the frequency of slope failure - and funding is being sought to do just this.

The team plans also to visit the coastal areas of Borneo to look for physical evidence of ancient tsunami and to model the type of waves that could hit the coastline.

Ben Sapiie, from the Bandung Institute of Technology in Indonesia, said: "This research enriches the Indonesian geological and geophysical communities' knowledge about sedimentation and landslide hazards in the Makassar Strait. The future of earth sciences research is using an integrated, multi-scientific approach with international collaborators."

Prof Dan Parsons is director of the Energy and Environment Institute at Hull University. His group also studies submarine landslides around the world.

He told BBC News: "What is interesting here is how these sediments are being re-worked and piled up over time in the Makassar Straight by oceanic currents.

"This sediment builds up and then fails when it gets unstable. What is then key is identifying the tipping point, or the trigger, that results in the failure. We have been doing similar work in fjords, exploring the multiple triggers and the magnitude and frequency of the failures that can occur.

"The biggest failures and the largest tsunami will likely occur when sediment delivery rate is very high but the triggers are infrequent, such that when the failures occur they are very large."

Indonesia experienced two landslide-driven tsunami events in 2018 - when the side of the Anak Krakatau volcano collapsed and separately when a quake triggered slope failures in Sulawesi's Palu Bay.

So awareness is certainly growing that tsunami can come from sources other than a seafloor megathrust earthquake like the one off Sumatra in 2004 which wreaked havoc right around the Indian Ocean.

President Joko Widodo announced last year that Indonesia would move its capital from Jakarta to Borneo.

The new administrative centre is to be built across two regencies - Kutai Kartanegara and North Penajam Paser - in East Kalimantan province, close to the existing cities of Balikpapan and Samarinda.

The seafloor study has been published by the Geological Society of London. BBC

 
 

Other News

.
Vietnam goes through 72 days without COVID-19 local transmissions
Vietnam goes through 72 days without COVID-19 local transmissions
SOCIETYicon  27/06/2020 

Vietnam has entered the 72nd day in a row without new COVID-19 infections among the community as of June 27 morning, according to the National Steering Committee for COVID-19 Prevention and Control.

Robots given to hospital to help protect frontline health workers from COVID-19
Robots given to hospital to help protect frontline health workers from COVID-19
SOCIETYicon  26/06/2020 

The United Nations Development Programme (UNDP) on Thursday donated three Ohmni Robots to the National Hospital for Tropical Diseases to help protect frontline doctors and nurses from COVID-19 and other infectious diseases.

Israel shares experiences with Vietnam in saving water in farming
Israel shares experiences with Vietnam in saving water in farming
SOCIETYicon  26/06/2020 

Drip irrigation – an effective Israeli invention that helps save water significantly – could be applied in Vietnam, particularly when part of Vietnam was heavily hit by droughts and saline intrusion, Israel’s agriculture expert said.


A

Indispensable dishes consumed during Doan Ngo festival
Indispensable dishes consumed during Doan Ngo festival
SOCIETYicon  26/06/2020 

With the Doan Ngo festival falling on the fifth day of May in the lunar calendar, the occasion usually kicks off the period of killing insects that harm the crops of farmers, 

Latest Coronavirus News in Vietnam & Southeast Asia June 26
Latest Coronavirus News in Vietnam & Southeast Asia June 26
SOCIETYicon  26/06/2020 

Vietnam enters 71st day without COVID-19 local transmissions

Vietnamese university among world’s best ‘Golden Age’ rankings 2020
Vietnamese university among world’s best ‘Golden Age’ rankings 2020
SOCIETYicon  26/06/2020 

The Hanoi University of Science and Technology has been named among the world’s best ‘Golden Age’ universities for 2020, according to the latest Times Higher Education World University Rankings.

Many people in HCM City quarantined following first diphtheria case
Many people in HCM City quarantined following first diphtheria case
SOCIETYicon  26/06/2020 

Sixteen people in HCM City have been quarantined after the city reported its first diphtheria patient.

Dong Nai to develop smart urban area near new airport
Dong Nai to develop smart urban area near new airport
SOCIETYicon  26/06/2020 

Prime Minister Nguyen Xuan Phuc has urged Dong Nai Province to speed up the progress of the Long Thanh International Airport and create a “comprehensive plan” to develop smart urban areas around the proposed airport. 

150 Japanese experts land at Van Don int’l airport
150 Japanese experts land at Van Don int’l airport
SOCIETYicon  26/06/2020 

Vietnam Airlines’ flight VN311 carrying 150 Japanese experts landed at Van Don international airport in the northern province of Quang Ninh on June 25 afternoon.

Tanzanite: Tanzanian miner becomes overnight millionaire
Tanzanite: Tanzanian miner becomes overnight millionaire
SOCIETYicon  26/06/2020 

Saniniu Laizer sold two Tanzanite stones, with a combined weight of 15kg, for £2.4m.

Gruesome “Body-in-concrete” case trial opens in Binh Duong
Gruesome “Body-in-concrete” case trial opens in Binh Duong
SOCIETYicon  26/06/2020 

Binh Duong Province People’s Court on Thursday opened a trial into four people implicated in a gruesome “corpse-in-concrete” case which happened in May last year. 

Three arrested for posting anti-State propaganda
Three arrested for posting anti-State propaganda
SOCIETYicon  26/06/2020 

Two women and a man have been arrested over the last two days in two separate cases of allegedly making, storing, and spreading anti-State material, according to police.

Ba Ria - Vung Tau to welcome 686 foreign experts
Ba Ria - Vung Tau to welcome 686 foreign experts
SOCIETYicon  26/06/2020 

The southern province of Ba Ria - Vung Tau is to have 686 more foreign experts working locally soon, the provincial Health Department revealed at a recent meeting of the local steering committee for COVID-19 control and prevention.

New Vietnamese language learning textbook launched
New Vietnamese language learning textbook launched
VIETNAM & WORLDicon  26/06/2020 

The Association for Liaison with Overseas Vietnamese held a ceremony on June 24 to introduce a new Vietnamese textbook entitled “Xin Chao Viet Nam” designed for overseas Vietnamese and foreigners who wish to learn the Vietnamese language.

Hanoi: 29 involved in Dong Tam disturbance prosecuted
Hanoi: 29 involved in Dong Tam disturbance prosecuted
SOCIETYicon  26/06/2020 

The Hanoi People’s Procuracy on June 25 prosecuted 29 people for killing three policemen in Dong Tam commune of the city’s My Duc district.

Time to tackle oversized trucks: official
Time to tackle oversized trucks: official
SOCIETYicon  27/06/2020 

Le Xuan Tien, Deputy Chief Inspector from the Hanoi Public Transport Department, talks on proposed sanctions for heavy and oversized trucks violating traffic laws in Hanoi's inner districts.

HCM City puts street vendors under better management, protects pedestrians
HCM City puts street vendors under better management, protects pedestrians
SOCIETYicon  26/06/2020 

Street vendors will be allowed to use sections of roads and pavements if they receive permission and pay fees for their business activities under a HCM City draft decision on road and pavement management.

USAID awards follow-on grant to Fulbright University Vietnam
USAID awards follow-on grant to Fulbright University Vietnam
SOCIETYicon  26/06/2020 

The US Agency for International Development (USAID) has awarded a $4.65 million grant to Fulbright University Vietnam (FUV).

Hanoi: Few pedestrians use footbridges, underground passages
Hanoi: Few pedestrians use footbridges, underground passages
SOCIETYicon  26/06/2020 

Many pedestrian bridges and underground passages in Hanoi are largely unused due to their inconvenience and safety concerns, according to baotintuc.vn.

Metal casting workers struggle under scorching temperatures
Metal casting workers struggle under scorching temperatures
SOCIETYicon  25/06/2020 

Despite enduring harsh conditions, combined with the recent spell of extremely hot weather, workers in My Dong metal casting village, Hai Phong have been attentively working to produce mechanical products for the local market.

 
 
 
Leave your comment on an article

OR QUICK LOGIN