28 Mar 2023
 | 28 Mar 2023

The seismic hazard from the Lembang Fault, Indonesia, derived from InSAR and GNSS data

Ekbal Hussain, Endra Gunawan, Nuraini Rahma Hanifa, and Qori’atu Zahro

Abstract. A growing number of large cities are located near poorly understood faults that have not generated a significant earthquake in recent history. The Lembang Fault is one such fault located near the city of Bandung in West Java, Indonesia. The slip rate on this fault is debated with estimates ranging from 6 mm/yr to 1.95–3.45 mm/yr, derived from GNSS campaign and geological measurements respectively. In this paper we measure the surface deformation across the Bandung region and resolve the slip rate across the Lembang Fault using radar interferometry (InSAR) analysis of 6 years of Sentinel-1 satellite data and continuous GNSS measurements across the fault. Our slip rate estimate for the fault is 4.7 mm/yr, with the shallow portions of the fault creeping at 2.2 mm/yr. Previous studies have estimated the return period of large earthquakes on the fault to be between 170–670 years. Assuming simplified fault geometries and a reasonable estimate of the seismogenic depth we derive an estimated moment deficit of a magnitude 6.8–7.2 earthquakes; indicating that the fault poses a very real risk to the local population. Using the Global Earthquake Model OpenQuake-engine we calculate ground motions for these two earthquake scenarios and estimate that 2.5–3.3 million people within the Bandung Metropolitan region would be exposed to ground shaking greater than 0.3 g. This study highlights the importance of identifying active faults and understanding their past activity, and measuring the current strain rates of smaller crustal active faults located near large cities in seismic zones.

Ekbal Hussain et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2022-1472', Anonymous Referee #1, 20 Apr 2023
  • RC2: 'Comment on egusphere-2022-1472', Anonymous Referee #2, 30 May 2023

Ekbal Hussain et al.

Ekbal Hussain et al.


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Short summary
The earthquake potential of the Lembang Fault, located near the city of Bandung in West Java, Indonesia is poorly understood. Bandung has a population of over 8 million people. We used satellite data to estimate the energy storage on the fault and calculate the likely size of potential future earthquakes. We use simulations to show that 2.5–3.3 million people would be exposed to high levels of ground shaking in the event of a major earthquake on the fault.