Baribis Fault Expedition, An Effort to Intensify Earthquake Mitigation in Jakarta

The Baribis Fault expedition team was introduced on Friday (26/4/2024) afternoon at the office of the Jakarta Regional Disaster Management Agency (BPBD) by BPBD, BRIN, and Skala Indonesia Foundation. In addition to Jakarta, the team will also explore Bogor, Karawang, Indramayu, Cirebon, Majalengka, Sumedang, Subang, Purwakarta, and Bekasi.

Also read: Baribis Fault Expedition Explores Jakarta Earthquake Potential and Mitigation

The Head of the Prevention Sub-Group of the DKI Jakarta Regional Disaster Management Agency (BPBD), Rian Sarsono, stated that many residents are unaware or forget that Jakarta is located in an earthquake zone and has experienced dozens of earthquakes since 1699. Even the BMKG reported a 4.5 magnitude earthquake in the Thousand Islands on August 14, 2023.

"People think that Jakarta never experiences earthquakes or that their tremors are insignificant, thus forgetting the record of dozens of earthquakes. Mitigation related to earthquakes must continue to be strengthened, including awareness of disaster impacts and existing infrastructure," said Rian.

Earthquakes can occur in Jakarta due to the existence of the Indo-Australian and Eurasian tectonic plates in the southern part of Java Island, with segments including East Java, Central-West Java, and the Sunda Strait with the potential for earthquakes up to magnitude 8.7.

Jakarta is also close to a number of faults, namely Baribis, Lembang, Cimandiri, Mount Salak, and Mount Gede Pangrango, which are being studied for their potential earthquake risks. Since last year, the Jakarta Provincial Government has formed a task force to assess buildings and non-buildings.

The task force consists of 122 personnel from various departments and relevant agencies/institutions. Their task is to assess the strength, readiness, and suitability of buildings and non-buildings, and integrate them into the SIDUGATAMI system (Earthquake-Resilient Building System).

This Baribis Fault tracing expedition is useful whatever the results.

These efforts run alongside socialization and disaster response simulations for the general public, in schools, hospitals, markets, places of worship, and building management. At least 50 activities are conducted each year within communities, schools, and buildings, as well as 20 district office buildings, and 30-40 other locations upon community request.

Along the Baribis Fault

Baribis Fault is one of the major fault zones in the western part of Java that follows the pattern of the island. This fault stretches from east to west with a route divided into several segments, such as Cipanas River, Ciremai, southern Jakarta, and the eastern side of Bekasi-Purwakarta.

BRIN Geological Disaster Research Center researcher Sonny Aribowo said that there are many active faults flanking Sumedang Regency, West Java, including the Baribis Fault in the Tampomas segment and the Ciremai segment, the Lembang Fault, the Cileunyi Tanjungsari Fault and the Garsela Fault. This fault stores swarn earthquakes or successive earthquakes with an average magnitude below Magnitude 5 and foreshocks (foreshock).

"The Baribis Fault Expedition is useful no matter what the results are, because unexpected earthquakes occur in areas that have not been previously studied, such as Cianjur, Sumedang, and the latest one near Bawean Island," said Sonny.

The tremors from the earthquakes in Cianjur and the Java Sea were felt up to Jakarta. The 5.6 magnitude earthquake in Cianjur Regency, West Java, on Monday (21/11/2022) afternoon was strongly felt for 3-5 seconds in Jakarta, which is 78 km to the southeast of the earthquake's epicenter. Meanwhile, the 6.9 magnitude earthquake on Friday (14/4/2024) evening, which originated in the Java Sea about 65 kilometers northwest of Tuban City, East Java, was felt as far as Jakarta and its surrounding areas.

Also read: Jakarta-Bogor, Prepare for Earthquakes

The Baribis Fault exploration is known as a continuation of the Palu-Koro expedition in Central Sulawesi. Both involve the participation of local residents, geology, anthropology, sociology, archaeology, architecture, disaster management practitioners, and travel or field discovery documentation teams.

The collaboration of various parties aims to obtain maximum data and results from the history, stories, local knowledge of local residents, and assessing the resilience of disasters from earthquake records that have occurred.

Director of the Skala Indonesia Foundation, Trinirmalaningrum, said that disaster preparedness requires many perspectives to be examined during the expedition. The result is in the form of disaster literacy in the form of books and films, campaigns through various platforms about history and the resilience of cities and villages in facing disasters.

"We are studying which areas in the south of Jakarta are included in the Baribis Fault. We are examining the history and determining what appropriate mitigation measures should be taken," said Trinirmalaningrum.

The Baribis Fault Expedition will start from Depok and Bekasi. Then, it will sequentially go to Tanjungsiang District in Subang, Ujungjaya and Tomo Districts in Sumedang, Tegalwaru and Sukatani Districts in Purwakarta, Jatigede and Talaga Districts in Majalengka, Kuningan and Cilimus in Kuningan, Terisi and Gantar in Indramayu, and Susukan Lebak and Kasepuhan in Cirebon.

Next, to Sukajaya, Pongkor, Bogor City, Ciampea, Tajurhalang, Bukit Rarata, and Kemang Bogor in Bogor, Margonda in Depok, Tangerang, and Jakarta.