Why is Southern Java Prone to Landslides?

What is the chronology of the landslide disaster in Cilacap and Banjarnegara?

In a short span of time, two regions in Central Java were struck by landslides that claimed lives. On Thursday (13/11/2025) at around 20:00 WIB, a landslide occurred in Cibeunying Village, Majenang District, Cilacap Regency.

The landslide disaster occurred after heavy rain fell since Thursday afternoon. The landslide then struck several residents' houses. Casualties from the disaster were unavoidable.

Meanwhile, on Sunday (16/11/2025) at around 15:30 WIB, a landslide disaster struck the settlement in Situkung Hamlet, Pandanarum Village, Pandanarum District, Banjarnegara Regency.

Residents of Situkung Hamlet, Ruswanto (51), stated that the landslide occurred very quickly. "It happened so fast, Sir. Suddenly the landslide came. I was outside near the house," he said when met on Tuesday (18/11/2025).

After learning about the landslide, Ruswanto quickly returned home to search for his family members. They then sought refuge in the forested area on the hills, where they were rescued by the search and rescue team and taken to the evacuation site.

How many victims were there from the landslides in Cilacap and Banjarnegara?

Based on data from the Cilacap Regional Disaster Management Agency (BPBD), as of Tuesday, there have been 18 fatalities in the landslide disaster. Meanwhile, five individuals are still missing.

The Assistant for Government and People's Welfare of the Cilacap Regional Secretariat, Sumbowo, stated that the handling of the landslide disaster in Cibeunying Village is ongoing. The search operation for missing victims is also continuing.

"Indeed, heavy machinery and volunteer teams are already quite numerous, but determining the location of the victims is challenging. The search dogs are also having difficulty because the soil is too deep, possibly beyond their scenting capability. The depth of the soil is about 3-4 meters," said Sumbowo.

In Banjarnegara, based on data from the Emergency Response Command Post for Landslides in Pandanarum District, the total number of residents affected by the disaster reached 937 individuals. As of Tuesday, there were 2 fatalities, while 26 others remain classified as missing.

The landslide disaster in Banjarnegara also resulted in 48 houses being severely damaged. Additionally, 134 houses, 3 stalls, and 2 prayer rooms were lightly damaged. The landslide also buried 800 meters of village roads and 670 meters of drainage. A total of 15 cattle and 125 goats were also affected.

What is the condition of the landslide locations in Cilacap and Banjarnegara?

The Head of the Data, Information, and Disaster Communication Center of the National Disaster Management Agency (BNPB), Abdul Muhari, stated that based on the analysis results from the Geological Agency, the area surrounding the landslide location in Cilacap has the potential to experience subsequent land movements.

The area is also classified as being within the medium landslide movement forecast zone. Based on morphological data, the location consists of hills with a gentle to steep slope. Geologically, the soil in this area is characterized by thick weathered soil, brown and loose, saturated with water, with a thickness of more than 10 meters.

Meanwhile, based on disaster assessment reports, the landslide location in Banjarnegara is situated on a slope ranging from moderate to extreme. At the crown or peak of the landslide, the slope is 80 degrees. The nearby area consists of rice fields with a terracing system and clusters of residential units.

The geological condition of the landslide location in Banjarnegara consists of sandstone, claystone, and andesite breccia. This layer of soil has formed over a long period from sedimentation, where the landslide area has experienced significant weathering.

According to geological data from Banjarnegara-Pemalang, the location of the landslide is not situated within an active fault or fracture zone. However, it is known that there are new cracks or fractures that continue to develop. During the rainy season, these cracks become saturated with water and are prone to movement.

The Head of the Rehabilitation and Reconstruction Division of the Regional Disaster Management Agency (BPBD) of Banjarnegara Regency, Junaedi, stated that cracks or fissures in the land at that location have been present since 2017. "However, they were not noticed and not reported by the community," he said.

What factors cause the southern region of Java to be prone to landslides?

During the Disaster Briefing on the Handling of the Cilacap Landslide, on Monday (17/11/2025) afternoon, Abdul Muhari stated that Central Java is one of the provinces most frequently affected by landslides and flash floods after West Java.

If viewed from its topography, both West Java, Central Java, and East Java have areas that are prone to landslides, primarily in the central to southern regions. In West Java, there are Garut, Tasikmalaya, and Ciamis. In Central Java, there are Cilacap, Banjarnegara, and Kebumen. Meanwhile, in East Java, there are Malang, Batu, and Trenggalek.

"If we look at its characteristics, the soil in West Java and Central Java, particularly in the central to southern regions, is loose. Its porosity is significant. For instance, if there are cracks, or even in the absence of cracks, when exposed to heavy rainfall, there is a risk of landslides. There is a saturation point, which will then cause the upper layer of soil to slide," explained Muhari.

The Professor of Geophysical Disaster Science and Natural Resource Exploration at Brawijaya University, Malang, Adi Susilo, stated that the central to southern part of Java Island is formed from limestone resulting from uplift from the sea. Limestone is a sediment from the sea that has subsequently been buried under layers of soil.

The soil layer in that area was once anchored by numerous plants. The roots of the plants penetrated deep and served as natural anchors. However, recently, many plants have begun to disappear due to human activities. On the other hand, the southern region of Java generally consists of hills with fairly steep slopes. This condition makes the area prone to landslides.