KamLAND Tohru Watanabe Dept of Earth Sciences University of Toyama Japan Todays Talk Geophysical observations around KamLAND Laboratory data on seismic velocities in rocks around KamLAND ID: 377352
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Slide1
Geophysical observations of the 100 km region around KamLAND
Tohru
Watanabe
Dept. of Earth Sciences
University of Toyama (Japan)Slide2
Today’s Talk
Geophysical observations around
KamLAND
Laboratory data on seismic velocities in rocks around
KamLANDSlide3
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) EPSLSlide4
Depth Contours of Pacific and Philippine Sea Plates
Nakajima et al. (2010)
KamLAND
NKTZSlide5
Seismological Studies on Crustal Structure
Nakajima et al. (2010)
NKTZ
Iidaka
et al. (2003)
Kato et al. (2006, 2007)
Nakajima et al. (2010)Slide6
Iidaka et al. (2003)
Seismic refraction survey
6 explosive sources
391 seismic stations
L~250 kmSlide7
P-wave velocity structure (
Iidaka
et al., 2003)
N
S
Toyama Plain (sediments)
KamLANDSlide8
Kato et al. (2006, 2007)
2006
2007
Travel-time
Tomography
Explosive
sources
+
Local Earthquakes
Nakajima et al. (2010)Slide9
P-wave velocity structure (Kato et al.,2007)
Toyama Plain (sediments)Slide10
Nakajima et al. (2010)
Nakajima et al. (2010)
Trave
l-time
TomographySlide11
P-wave velocity perturbations
D=0 km
D=5 km
D=10 km
D=15 km
D=25 km
D=40 km
Nakajima et al. (2010)Slide12
Structure along Atotsugawa
Fault
Hakusan
Tateyama
Nakajima et al. (2010)Slide13
Velocity Perturbations across Atotsugawa
Fault
S
N
Nakajima et al. (2010)Slide14
Summary of Seismological Observations
Seismological observations have revealed
A complicated configuration of
subducted
plates
Low velocity regions associated with active volcanoes
Surface low velocity regions caused by thick sedimentsSlide15
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)Slide16
Surface geology around
KamLAND
after Yamada et al. (1989)
11 rock samplesSlide17
P-wave Velocity vs Confining Pressure
D~
7km
D~2
km
Granodiorite
(TKA-b1)Slide18
Density vs
Vp
(180MPa)
Hida
granites
Hida
metamorphic rocksSlide19
Vs vs
Vp
(180
MPa
)
Hida
granites
Hida
metamorphic rocksSlide20
Comparison with Observed Velocity
Hida
metamorphic rocks (+
Hida
granites)
Kato et al. (2007)
KamLANDSlide21
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
Slide22
Measured Velocity at High T and High P
Nishimoto
et al. (2008)
D~25 kmSlide23
Inference of Lower Crustal Material
Nakajima et al. (2010)
D=25 km
Rock +
aqueous fluids
D=25 kmSlide24
Pyroxene
amphibolite
Hornblende-pyroxene
gabbro
Nakajima et al. (2010)Slide25
Summary of Laboratory Data
Upper and middle crust
Hida
metamorphic rocks
Hida
granites
Lower crust
Pyroxene
amphibolite Hornblende-pyroxene gabbro Slide26Slide27