The evolution of Sidoarjo hot mudflow (Lusi), Indonesia

Abstract

A spectacular hot mudflow in Sidoarjo on May 29, 2006 seized the attention of many people ranging from the general public, government, to experts related from within the local and abroad. Sidoarjo hot mudflow until now still flowing and this geological evidence has not shown any signs of stopping in the near future and causing a great impact on the surrounding environment and socio-economic life of the community as well as raising other speculation against to this geological evidence.The regional geology of hot mud discharge areas in between the edge of a volcanic arc and back arc basin. This event shows the discharge of material from subsurface layer containing a higher pressure clay from hydrostatic pressure (over pressure shale), very plastic and possibly even in mobile (hydrodynamic) conditions. It is very common in the ellisional basin called mud volcano, although there are differences in the characteristics of LUSI with other mud volcanoes, which are temperature about 100 °C on the surface with a discharge of 150,000 m3 / day. For nearly 12 (twelve) years of flowing, observation activities and measurement of characteristics and behavior continue to be convergence with geological, geochemical, geophysical and geodetic approaches.The results of the fluid geochemical analysis show that LUSI has already related to geothermal phenomena [16,18]. The result of geological structure analysis shows the existence of piercement structure crossing through the center of eruption while the geodesy analysis using InSAR indicates there are some areas that subsidence and some are uplifted [1] . Based on the results of various approaches and a comprehensive analysis shows that the hot mudflow Sidoarjo has evolved for characteristics, the ratio of the enlarged water, the constant temperature around 100 °C that show to the of volcano signature or it is making of the Neovolcanism.