Abstrak
This study concerns the activities, forms, and spread of mud eruption in Ciuyah as a part of Java-Madura axial depression zone. Landsat interpretation and detailed field observation were conducted to find out the eruption activity, the conduit system, and the host rock. Both physical and chemical properties of erupted material were tested to track down the mud origin, movement dynamic, and changes during transportation. Active bubbling which bring fluid, claystone- to sandstone-size solid particles, gas, and heat as well as crusting material inside conduits are detected in Ciuyah. The high similarity of rock composition and fossil contained indicated that the mud comes far below the surface passes the rock layers of the Late Tertiary sedimentary rock (Pemali and Halang Formations), and then ejected to the surface through conduits. The temperature of extruded mud reaches 6.9° to 13.6° compared to air temperature (hyperthermal). Conduits where the mud comes out mostly show NW-SE direction as a minor pattern of existing morphological lineament directions. Changes seen in pH, TCD and EC, besides hydro-chemical composition (level of Na+ , Cl- , SiO2, Mn2+, K+ , Li+ , Fe3+, Mg2+ , HCO3 – , Ca2+ and SO4 – ) caused by water formation as well as minerals enrichment dissolved due to heat and long-time contact to the side rock during eruption.
