| Title | Microearthquake (MEQ) Investigation Reveals the Sumatran Fault System in Hululais Geothermal Field, Bengkulu, Indonesia |
|---|---|
| Authors | Aditya A. JUANDA, Astha D. K. WARDHANI, Imam B. RAHARJO |
| Year | 2015 |
| Conference | World Geothermal Congress |
| Keywords | Sumatran fault system Musi and Ketaun segment, Hululais geothermal field, microearthquake (MEQ), single event determination, joint hypocenter determination |
| Abstract | Hululais field is located in Bengkulu province, about 30 km north of the Bengkulu city. During April to July 2012, microearthquake (MEQ) monitoring was undertaken for about 120 days consisting of 6 surface stations (three channels each, 4.5 Hz natural frequency and 200 sps sampling rate). Numbers of events were detected with magnitude ranging from 0.1 up to 2. The P and S wave arrival times of each event are manually revised the picking and the hypocenters determinations are determined by applying the Single Event Determination (SED) and Joint Hypocenter Determination (JHD) techniques. The hypocenter distributions from both techniques are similar however the JHD results have smaller error RMS and location parameters. The hypocenter distribution pattern depicts the Sumatran fault system with its associated faults within Musi and Ketaun segment that dominantly have a NW – SE trend. Three clusters of hypocenter are observed with depth varying from 1 to 10 km. There is MEQ cluster depict faults or fractures zone from the Musi segment. There are also two clusters that clearly show faults system in Ketaun segment, one has relatively the same orientation with fault plane in the Musi segment and the other one has opposite orientation with relatively the same dip magnitude. The clusters of faults are regarded as high permeable regions. By far these faults regions have been the main target for exploration drilling in Hululais field. |