%0 Journal Article %1 julian_etal:2002 %A Julian, Bruce R. %A Pitt, A. M. %A Foulger, G. R. %C US Geological Survey, 345 Middlefield Road MS977, Menlo Park, 94025 CA, USA. E-mail; Department of Geological Sciences, University of Durham, Durham, DH1 3LE, UK %D 2002 %J Geophysical Journal International %K geophysics seismology %N 1 %P F7--F10 %R 10.1046/j.1365-246X.1998.1331540.x %T Seismic image of a CO2 reservoir beneath a seismically active volcano %U http://dx.doi.org/10.1046/j.1365-246X.1998.1331540.x %V 133 %X Mammoth Mountain is a seismically active volcano 200 000 to 50 000 years old, situated on the southwestern rim of Long Valley caldera, California. Since 1989 it has shown evidence of unrest in the form of earthquake swarms (Hill et al. 1990), volcanic 'long-period' earthquakes (Pitt & Hill 1994), increased output of magmatic 3He (Sorey et al. 1993) and the emission of about 500 tonnes/day of CO2 (Farrar et al. 1995; Hill 1996; M. Sorey, personal communication, 1997), which has killed trees and poses a threat to human safety. Local-earthquake tomography shows that in mid-1989 areas of subsequent tree-kill were underlain by extensive regions where the ratio of the compressional and shear elastic-wave speeds VP/VS was about 9 per cent lower than in the surrounding rocks. Theory (Mavko & Mukerji 1995), experiment (Ito, DeVilbiss & Nur 1979), and experience at other geothermal/volcanic areas (Julian et al. 1996) and at petroleum reservoirs (Harris et al. 1996) indicate that VP/VS is sensitive to pore-fluid compressibility, through its effect on VP. The observed VP/VS anomaly is probably caused directly by CO2, and seismic VP/VS tomography is thus a promising tool for monitoring gas concentration and movement in volcanoes, which may in turn be related to volcanic activity.

@article{julian_etal:2002, abstract = {Mammoth Mountain is a seismically active volcano 200 000 to 50 000 years old, situated on the southwestern rim of Long Valley caldera, California. Since 1989 it has shown evidence of unrest in the form of earthquake swarms (Hill et al. 1990), volcanic 'long-period' earthquakes (Pitt \& Hill 1994), increased output of magmatic 3He (Sorey et al. 1993) and the emission of about 500 tonnes/day of CO2 (Farrar et al. 1995; Hill 1996; M. Sorey, personal communication, 1997), which has killed trees and poses a threat to human safety. Local-earthquake tomography shows that in mid-1989 areas of subsequent tree-kill were underlain by extensive regions where the ratio of the compressional and shear elastic-wave speeds VP/VS was about 9 per cent lower than in the surrounding rocks. Theory (Mavko \& Mukerji 1995), experiment (Ito, DeVilbiss \& Nur 1979), and experience at other geothermal/volcanic areas (Julian et al. 1996) and at petroleum reservoirs (Harris et al. 1996) indicate that VP/VS is sensitive to pore-fluid compressibility, through its effect on VP. The observed VP/VS anomaly is probably caused directly by CO2, and seismic VP/VS tomography is thus a promising tool for monitoring gas concentration and movement in volcanoes, which may in turn be related to volcanic activity.}, added-at = {2012-09-01T13:08:21.000+0200}, address = {US Geological Survey, 345 Middlefield Road MS977, Menlo Park, 94025 CA, USA. E-mail; Department of Geological Sciences, University of Durham, Durham, DH1 3LE, UK}, author = {Julian, Bruce R. and Pitt, A. M. and Foulger, G. R.}, biburl = {https://www.bibsonomy.org/bibtex/2ece4b9c79374fab87eb985b4b70276d8/nilsma}, doi = {10.1046/j.1365-246X.1998.1331540.x}, interhash = {55a4b9c4d1a1409afb4a7c99b10134bf}, intrahash = {ece4b9c79374fab87eb985b4b70276d8}, issn = {1365-246X}, journal = {Geophysical Journal International}, keywords = {geophysics seismology}, month = apr, number = 1, pages = {F7--F10}, timestamp = {2021-02-09T13:27:05.000+0100}, title = {Seismic image of a CO2 reservoir beneath a seismically active volcano}, url = {http://dx.doi.org/10.1046/j.1365-246X.1998.1331540.x}, volume = 133, year = 2002 }