Recent hydrothermal systems of Kamchatka

Study of the largest manifestations of the recent hydrothermal activity in Uzon-Semyachik, Pauzhetka-Kambalny and other regions in Kamchatka enable us to conclude: in the area of recent volcanism characterized by a general increase of conductive heat flow, some regions can be distinguished with an especially intense geothermal regime specified by an additional supply of heat by deep fluids. Within such anomalies the formation of hydrothermal systems can be observed. Recent hydrothermal systems of Kamchatka are natural hydrodynamic systems belonging to the type of small artesian basins and artesian slopes having porous-bedded, fissure-bedded and more seldom fissure-veined permeability and containing high-temperature underground waters. They are associated with volcano-tectonic grabens and circular depressions filled with a series of tufaceous material of mainly acid composition and two-membered structure. Localization of certain thermal manifestations within the systems is determined by disjunctive tectonics and outflows of thermal waters to the surface. The same factors are responsible for the position of the recharge areas of the systems with infiltration waters forming the main mass of their water reserves. Usual hydrodynamic methods can be used for a quantitative estimation of these reserves. Heat recharge of the systems is realized by the supply of an over-critical fluid. This is confirmed by hydrogeothermal data, similarity of the chemical composition of high temperature hydrothermal water and their thermo-physical parameters. Manifestations of hydrothermal activity do not reveal any connection with recent andesite-basaltic volcanism of Kamchatka; on the contrary, they are associated with the acid volcanism of the Middle and Upper Pleistocene stage of its geological history, testifying to their genetic similarity. Hydrothermal activity is one of the manifestations of the general geothermal activity of the interior. It is closely related, in time and space, to a certain stage of the volcano-plutonic process and tectonic evolution of mobile belts. The perspectives of obtaining heat and electric energy from hydrothermal systems are considered

ON THE CONDITIONS OF WATER AND HEAT FEEDING OF THE PAUZHETKA HYDROTHERMAL SYSTEM (SOUTH KANCHATKA, USSR)

The Pauzhetka hydrothermal system is located in a volcano-tectonic depression near active volcanic centers. Temperatures at depths of 300-800 m are 180-210 C. The natural discharge of the hydrothermal system includes the discharge of the Pauzhetka springs and a concealed discharge in the bed of the Pauzhetka River (95 kg/s) and the steam discharge in the Kambalny Ridge (15 kg/s). Only the upper part of geothermal reservoir was penetrated by drillholes (up to 1200 m), therefore they have used a mathematical modeling to assess the conditions of water and heat feeding of the hydrothermal system. The hydrothermal system belongs to a linear fracturing zone of NW trend, therefore the two-dimensional model was used in the calculations. It has been defined that (1) the source of heating is a magma chamber located at a shallow depth; (2) the heat and mass transfer in the geothermal reservoir is defined by free and forced hydraulic convection, (3) the conductivity coefficient of a linear fracturing zone is 400-600 m{sup 2}/day, its width is 2 km and length is 10 km, and (4) the water feeding is defined by infiltration in the recharge area. Calculations of temperature and velocity fields agree with real data obtained in the Pauzhtka geothermal area, therefore they may be a base for assessment of water and heat feeding of the hydrothermal system. In accordance with these assessments, the main part of water resources is derived from infiltration. Heat feeding may be maintained by cooling of the magma chamber with a volume of 18 km{sup 3} that is in accordance with the volume of Holocene igneous rocks

The Coupling of the Numerical Heat Transfer Model of the Pauzhetka Hydrothermal System (Kamchatka, USSR) with Hydroisotopic Data

The application of the two-dimensional numerical heat-transfer model to the Pauzhetka hydrothermal system allowed us to establish that: (1) a shallow magma body with the anomalous temperature of 700-1000 C and with a volume of 20-30 km{sup 3} may be a heat source for the formation of the Pauzhetka hydrothermal system. (2) The water feeding source of the Pauzhetka hydrothermal system may be meteoric waters which are infiltrated at an average rate of 5-10 kg/s {center_dot} km{sup 2}. The coupling of the numerical heat-transfer model with hydroisotopic data (D,T,{sup 18}O) obtained from the results of testing of exploitation wells, rivers and springs is the basis to understand more clearly the position of recharge areas and the structure of water flows in the hydrothermal system

On the possibility of using heat stored in the magma chamber of the Avachinsky volcano and the surrounding rock for heat and power supply

The results of geological and geophysical studies, including recent ones, which make it possible to verify the existence of a liquid magma chamber below the Avachinsky volcano on Kamchatka, and to estimate the chamber depth and approximate dimensions, are analyzed. The heat stored in the host rock heated by the volcanic magma chamber from the time of chamber origination to the present is estimated, taking variable chamber dimensions during the process of evolution into account. The geological-geophysical prerequisites for using the thermal energy of the heated rock which surrounds the magma chamber to supply heat and power to Petropavlovsk-Kamchatskii are analyzed. The creation of an underground geothermal circulation system (fracture heat exchanger) using deep boreholes is proposed

On a Possibility of Heat Utilization of the Avachinsky Volcanic Chamber

The sources of geothermal energy of Kamchatka are hydrothermal systems, local blocks of high heated rocks, and peripheral magma chambers of active volcanoes in particular. According to gravimetric, magnetic and seismic data, under the Avachinsky volcano there exists an anomalous zone which is suspected to be a peripheral magma chamber. It is localized at the boundary of the Upper Cretaceous basement and an overlying volcanogenous stratum at a depth of 1.5 km from sea level. Its geophysical data are as follows: the radius is 5.2±0.9 km; the density of rocks is 2.85 to 3.15 g/cm3, the velocity of longitudinal waves is 2200 m/sec, the viscosity of rocks is 105 to 108 poise. The temperature distribution in the near-chamber zone was calculated by clcctrointegrator at 0°C at the Earth's surface and 1000°C at the chamber surface for stationary and non-stationary (the period of 20 000 years) heating. Heat extraction may be possible if a system of artificial jointing iscreated. The capacity of a thermal reservoir with a volume of one cubic km at a depth of 5 km and a distance of 6 km from the volcano would be 2 x Ю14 kcal, extractable under non-stationary conditions, which could provide the work of power stations with a total capacity of 250 MW for a period of 100 years