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Geophysical observations of the 100 km region around KamLAND Tohru Watanabe Dept. of Earth Sciences University of Toyama (Japan)
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Today’s Talk 1.Geophysical observations around KamLAND 2.Laboratory data on seismic velocities in rocks around KamLAND
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Toyama KamLAND Niigata-Kobe Tectonic Zone (High strain-rate zone) Atotsugawa Fault 1858 Hiestu Earthquake (M7) Geophysical Observations Seismological Obs. MT surveys Gravity Obs. 1. Geophysical Observations Iio et al. (2002) EPSL
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Depth Contours of Pacific and Philippine Sea Plates Nakajima et al. (2010) KamLAND NKTZ
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Seismological Studies on Crustal Structure Nakajima et al. (2010) NKTZ Iidaka et al. (2003) Kato et al. (2006, 2007) Nakajima et al. (2010)
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Iidaka et al. (2003) Seismic refraction survey 6 explosive sources 391 seismic stations L~250 km
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P-wave velocity structure (Iidaka et al., 2003) NS Toyama Plain (sediments) KamLAND
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Kato et al. (2006, 2007) 2006 2007 Travel-time Tomography Explosive sources + Local Earthquakes Nakajima et al. (2010)
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P-wave velocity structure (Kato et al.,2007) Toyama Plain (sediments)
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Nakajima et al. (2010) Travel-time Tomography
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P-wave velocity perturbations D=0 kmD=5 kmD=10 km D=15 kmD=25 kmD=40 km Nakajima et al. (2010)
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Structure along Atotsugawa Fault HakusanTateyama Nakajima et al. (2010)
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Velocity Perturbations across Atotsugawa Fault S N Nakajima et al. (2010)
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Summary of Seismological Observations Seismological observations have revealed (1) A complicated configuration of subducted plates (2) Low velocity regions associated with active volcanoes (3) Surface low velocity regions caused by thick sediments
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2. Laboratory Data on Seismic Velocity Upper, Middle Crust (D<10 km) Kagami and Watanabe (2009) Surface rocks Lower Crust (D>20 km) Nishimoto et al. (2008) Xenoliths (Rocks collected by magma during its ascent)
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Surface geology around KamLAND after Yamada et al. (1989) 11 rock samples
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P-wave Velocity vs Confining Pressure D~7kmD~2km Granodiorite (TKA-b1)
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Density vs Vp (180MPa) Hida granites Hida metamorphic rocks
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Vs vs Vp (180 MPa) Hida granites Hida metamorphic rocks
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Comparison with Observed Velocity Hida metamorphic rocks (+Hida granites) Kato et al. (2007) KamLAND
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Ichino-megata KamLAND Ichino-megata mafic-ultramafic xenoliths Lower Crust Xenoliths Iio et al. (2002) EPSL Nishimoto et al. (2008) (1) Hornblende gabbro (2) Hornblende-pyroxene gabbro (3) Amphibolite (4) Pyroxene amphibolite (5) Hornblendite
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Measured Velocity at High T and High P Nishimoto et al. (2008) D~25 km
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Inference of Lower Crustal Material Nakajima et al. (2010) D=25 km Rock + aqueous fluids D=25 km
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Pyroxene amphibolite Hornblende-pyroxene gabbro Nakajima et al. (2010)
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Summary of Laboratory Data Upper and middle crust Hida metamorphic rocks Hida granites Lower crust Pyroxene amphibolite Hornblende-pyroxene gabbro
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