The 8 x 16 km Suoh (or Suwoh) depression appears to have a dominantly tectonic origin, but contains a smaller complex of overlapping calderas oriented NNE-SSW. Historically active maars and silicic domes lie along the margins of the depression, which falls along the Great Sumatran Fault that extends the length of the island. Numerous hot springs occur along faults within the depression, which contains the Pematang Bata fumarole field. Large phreatic explosions (0.2 km2 tephra) occurred at the time of a major tectonic earthquake in 1933. Very minor hydrothermal explosions produced two 5-m-wide craters at the time of a February 1994 earthquake.
Steam clouds rise above the Danau Asam fumaroles on the west side of lake Asam within the 8 x 16 km Suoh depression in SE Sumatra. Numerous hot springs occur along faults within the depression, which contains the Pematang Bata fumarole field. Prior to the largest explosive eruption in Sumatra during historical time, which took place in 1933, the floor of the Suoh depression was a broad marsh 13 km long in a NNW-SSE direction. The depression appears to be primarily of tectonic origin, but contains historically active maars and silicic domes along its margins.
Anonymous photo, 1990.
Last updated 2019-08-04 00:28:02