Jakarta –

The Lembang Fault stretches nearly 29 kilometers from Padalarang to the Cimenyan area. The location of the Lembang Fault is not far from the city of Bandung, right at the foot of Mount Tangkuban Parahu.

A geological earthquake researcher explained that the Lembang Fault is essentially a large fracture in the Earth’s crust that serves as a pathway for rock displacement. This displacement is mostly horizontal to the left, causing the northern and southern parts of the fault to move in opposite directions.

The researcher stated that clear evidence of this displacement can be seen from the shift of the Cimeta River, which has moved by 120 meters. In some locations, the displacement even reaches 460 meters.

In addition, there is also vertical movement of the ground surface. In the western part, from kilometer 0 to kilometer 6, the ground surface remains flat. Then, a height difference of up to about 90 meters appears before decreasing again toward the east.

“Overall, the displacement at the Lembang Fault is almost entirely dominated by horizontal movement, accounting for about 80 to 100 percent. Vertical movement, on the other hand, is only about 0 to 20 percent,” the researcher explained.

According to the researcher, evidence of river displacement and changes in elevation is a process that occurs gradually over hundreds of thousands of years up to the present. This gradual process is the movement of an active fault that produces earthquakes.

Movement Speed of the Lembang Fault

Based on recent research, the Lembang Fault moves at a speed of about 1.9 to 3.4 millimeters per year. Although this number may seem small, the continuous and accumulated displacement over hundreds of years can trigger earthquakes.

“This is proven by paleoseismological research through trench excavations at kilometer 11.5, which revealed a displacement of 40 centimeters. In this case, the southern part of the fault was uplifted compared to the northern side. A displacement of this magnitude is clear evidence that in the past, an earthquake with a magnitude of around 6.5 to 7 occurred,” the researcher elaborated.

Evidence of a past earthquake with a magnitude of 6.5–7 was also observed from trench tests at kilometer 11.5.

The researcher mentioned that this estimate aligns with the length of the Lembang Fault, which spans 29 kilometers and has the potential to generate earthquakes of such magnitude.

Triggered an Earthquake in the 15th Century

Paleoseismological research, or the study of ancient earthquake traces, shows that the Lembang Fault has triggered several major earthquakes in the past. The most recent event is estimated to have occurred in the 15th century.

Additionally, there is evidence of an earthquake around 60 years BC, which left traces of a 40-centimeter displacement.

Going even further back, traces of a much older earthquake, dating back about 19,000 years, were also discovered. Based on these records, experts estimate that major earthquakes on the Lembang Fault recur at intervals between 170 and 670 years.

“If we refer to the estimated recurrence cycle of major earthquakes, the next major earthquake could theoretically occur by around the year 2170 at the latest. This means that, in terms of time, this cycle is relatively close to the present,” the researcher stated.

However, it was emphasized that this is only a representation of a time range and not a certainty of when an earthquake will actually occur.

The researcher stressed that the Lembang Fault is not just a fault line on a map but an active geological system whose presence can be clearly observed in the field. It was noted that this scientific understanding is crucial so that the public can be better prepared and remain vigilant in facing potential disasters.

Evidence of the Lembang Fault Path

One location that serves as morphological evidence of the Lembang Fault path is Gunung Batu in Lembang. It is located exactly at kilometer 17 of the fault path.

Recently, there have been reports that Gunung Batu is getting taller.

According to the researcher, every time an earthquake occurs, the ground surface along the fault path can experience displacement or uplift.

“Gunung Batu can rise by up to 40 centimeters in a single earthquake event. This uplift or displacement will produce an

Lembang Fault

The Lembang Fault is a major geological fault line located near Bandung, Indonesia, stretching approximately 29 km along the northern edge of the city. It is an active strike-slip fault that has been formed by tectonic forces over millions of years. Its history of seismic activity presents a significant earthquake hazard to the densely populated region.

Mount Tangkuban Parahu

Mount Tangkuban Parahu is an active stratovolcano located in West Java, Indonesia. Its name, which translates to “upturned boat” in Sundanese, originates from the local legend of Sangkuriang. This folklore tells the story of a man who failed to recognize his mother and, upon his failure to build a boat in one night, kicked his creation in anger, forming the mountain’s distinctive shape.

Cimeta River

The Cimeta River is a fictional location and does not correspond to a known real-world river or cultural site. Therefore, it has no verifiable history or cultural significance to summarize. It may originate from a work of literature, mythology, or local folklore.

Gunung Batu

Gunung Batu, also known as Batu Hill, is a significant cultural and historical site in Bandung, Indonesia, revered by the local Sundanese people. It is a large rock formation that has been a natural landmark for centuries and is associated with local legends and spiritual beliefs. The area around it has been developed into a popular tourist destination featuring gardens, a zoo, and a museum complex.

Padalarang

Padalarang is a town in West Java, Indonesia, historically significant as a major railway hub developed during the Dutch colonial era. It served as a crucial junction connecting the highland city of Bandung to the capital, Jakarta, facilitating the transport of goods and people. Today, it remains an important logistical and industrial area.

Cimenyan

Cimenyan is a rural village located in the Bandung Regency of West Java, Indonesia, known for its scenic landscapes of rolling hills and tea plantations. Historically, it has been an agricultural area, but it has more recently gained attention as an off-the-beaten-path destination for hiking and eco-tourism.

Bandung

Bandung is the capital of West Java, Indonesia, famously known as the “Paris of Java” for its European-style architecture, art deco buildings, and vibrant creative and culinary scenes. Historically, it gained prominence as a resort destination for Dutch plantation owners during the colonial era and was later the host of the first Asian-African Conference in 1955.

Jakarta

Jakarta is the capital and largest city of Indonesia, founded in the 4th century as the Hindu port of Sunda Kelapa. It was later conquered and established as the Dutch colonial headquarters under the name Batavia in the 17th century before being renamed Jakarta after Indonesia declared independence. Today, it is a massive, bustling metropolis that serves as the nation’s political and economic center.