Variation of Rock Electrical Resistivity in Andesitic-Trachytic Volcanic Geothermal Areas. A Case Study of Lili-Sepporaki, Sulawesi island- Indonesia

Abstract

The objective of this paper is to investigate how electrical resistivity changes as electromagnetic waves penetrate deep into the subsurface of Lili-Sepporaki geothermal prospect, using Magnetotelluric data. Lili Sepporaki is an andesitic-trachytic volcanic-rich area located in western Sulawesi-Indonesia. Magnetotelluric data was processed using SSMT2000 and MTEditor software programmes. Results show that resistivity of rocks generally increases with decreasing frequency, that is; less than 100 Ohm-m for frequencies greater than 100 Hertz; and fluctuates between 100-1000 Ohm-m for frequency range 1-0.1 Hertz. Resistivity also increases with depth of penetration of electromagnetic waves. Weathering, hydrothermal alteration, and many times fluids increase the conductivity of rocks. A low resistivity anomaly is seen around the hot spring, northwards. Presence of fluids in an intensively fractured volcanic rock lowers its resistivity. In the future, another Magnetotelluric sounding should be carried with much more measurement stations followed by a three-dimensions interpretation.

Sediment Transport and Suspension Analysis to Support Development Planning for Port Pota, East Nusa Tenggara, Indonesia

“…The port serves as the center of the community's economy, used for the purposes of entry and exit of goods (exports and imports) and human activities. In order to be in accordance with its functions, a complete port must have a pier, breakwater, port pool, shipping lanes, passenger and goods terminals, fish landing terminals, processing , and waste disposal facilities (reception facilities/garbage and sewage treatment and disposal facilities), emergency response systems, as well as port operation supporting facilities such as warehouses, container processing facilities, stacking yards, fish auction places, cold storage for fishery products, road networks, electricity networks, telecommunications networks, clean water networks, drainage networks, various loading and unloading equipment, workshops and different hydro-acoustic surveys [1][2][3] Suspended sediment mainly consists of sediment types, namely fine sand, silt, and clay (with an average size of 63 m), carried to rivers and streams from the highlands and transported downstream [4][5][6] . Over time, under certain conditions, such as reduced flow velocity and momentum, sediment can, therefore, temporarily accumulate in channels or riverbeds, and under most common hydraulic systems, entrained and remobilized sediments return to the outflow [7][8].…”

Synthesis of Silica Coating Derived from Geothermal Solid Waste Modified with 3-Aminopropyl Triethoxysilane (APTES) and Silver Nano Particles (AgNPs)

“…The remaining contents of the geothermal solid waste consist of several inorganic materials in trash composition, such as arsenic, barium, boron, cadmium, chromium, copper, lead, mercury, selenium, silver, and zinc 24) . The selection of geothermal solid waste as a source of silica is very appropriate due to its geothermal abundance potential of approximately 28 GW [25][26][27] .…”