BRIN Finds Rekahan Allegedly Cianjur Earthquake Fault Line

Rekahan is suspected of being part of the fault lane that caused the earthquake in Cianjur Regency, West Java, Friday (28/7/2023). (ANTARA/Asep Firmansyah)

JAKARTA - Researchers from the National Research and Innovation Agency (BRIN) found fractures that were suspected of being part of the fault line/earthquake that hit Cianjur Regency in November 2022.

"So we found a fairly wide fracture and then caused the foundation of the pool wall to move approximately 15 cm to the right," said Head of the Geological Research Center for the Ground and Maritime Research Organization BRIN Adin Tohari in Cianjur as reported by ANTARA, Friday, July 28.

The discovery of the fracture was in Rawa Cina Village, Nagrak Village. The village became one of the locations that was destroyed by an earthquake with a magnitude of 5.6.

Rekahan, which has a depth of 15 cm, is known from the foundation of the fish pond rock that shifted to the right. With this fracture, BRIN researchers suspect the fault caused damage to the building.

To prove this hypothesis, researchers are still conducting geophysics research to determine whether the fracture is associated with fractures from within the soil.

"With this fracture, we believe that below there are faults that cause severe damage to buildings. Now we want to prove it with research," he said.

The foundation of the pond extends up to 25 meters to the north, but his party cannot identify further the length of the fracture because it is covered in building debris.

Meanwhile, to the south, the length of the fracture was identified as far as 10 meters or towards the residents' rice fields. He suspects that the location is one part of the fault line which extends to the vicinity of the Tapal Kuda Cugenang area.

"The people here are telling stories about the shaking (up and down) not swinging again. This (up and down) means very close to the source of the earthquake, so it's shaking," he said.

However, researchers still need further confirmation of these allegations through research by Geoelectric Multichanel Resistivity and Ground Penetrating Radar.

The results of the study are targeted to be completed in December 2023, so that it becomes a guide in mapping areas of earthquake risk and targeted mitigation measures.

In line with Adrin, one of the residents of Rawa Cina Yuyun Yunengsih (48) told that the earthquake felt very strong and made the house seem to jump. The sound of an earthquake was like a lightning explosion.

He admitted that he had never felt an earthquake with the characteristics of shaking up and down. Usually, if an earthquake occurs around the south of West Java, the vibrations only swing.

"(The sound) exploded upward, (the atmosphere) immediately went dark. The house went up and down. The pool immediately broke, the fish ran out. There were four houses that collapsed into the ground," he said.