| Title | Geofluids of Avachinsky-Koryaksky Volcanogenic Basin, Kamchatka, Russia |
|---|---|
| Authors | Alexey KIRYUKHIN, Yuri MANUKHIN, Sergey FEDOTOV, Vasily LAVRUSHIN, Tatiana RYCHKOVA, Gennady RYABININ, Andrey POLYAKOV, Pavel VORONIN |
| Year | 2015 |
| Conference | World Geothermal Congress |
| Keywords | Avachinsky, Koryaksky, volcanogenic, basin, methane, magma, aquifers, CO2 springs |
| Abstract | Avachinsky-Koryaksky volcanogenic basin with area of 2530 km2 is located in the city of Petropavlovsk-Kamchatsky city and includes five quaternary volcanoes (two of which Avachinsky (2750 m.a.s.l.) and Koryaksky 3456 (m.a.s.l.) are active), sub-basins of volcanogenic and sedimentary Neogen-Quaternary deposits, located in a depression formed at the top of Cretaceous basement rocks. Magma fluids emplacement zones are clearly detected by local earthquakes distributions below Koryaksky and Avachinsky volcanoes at depth elevations -5.5 - +2.0 km and -1.5 - +2.0 km correspondingly, water isotope (ƒÂD, ƒÂ18O) data shows, that those volcanoes are also acts as recharge areas for adjacent the thermal mineral springs (Koryaksky Narzans, Isotovsky and Pinachevsky) and wells of the Bystrinsky aquifer. ƒÂ13„R in „R„O2 from CO2 springs in NW foothills of Koryaksky volcano are formed as a result of mixing of magmatic gases and melting glaciers waters. High sensitivity of thermal springs to regional and local seismic activity events pointed to hydraulic connection between magma emplacement zone beneath Korykasky volcano, adjacent hydrothermal systems and methane reservoirs. Hydrodynamic TOUGH2-EOS9 model of Avachinsky-Koryaksky volcanogenic basin was developed and calibrated, based on water level data in 13 deep wells. Inverse modeling yield estimates for the total rate of meteoric recharge 6 m3/s and maximum groundwater head below volcanoes +900 m.a.s.l. It is proposed, that shallow methane CH4 reservoirs penetrated by wells in Neogene - Quaternary layer around Koryaksky and Avachinsky volcanoes, and Pinachevsky extrusions may be formed as a result of heating from magma emplacement reservoirs beneath volcanoes to hosted gas hydrates and organic sediments. The area of potential methane accumulation is accounted ~650 km2. |