Transcript J R Kayal Geological Survey of India Kolkata e-mail:
J R Kayal Geological Survey of India Kolkata e-mail: [email protected]
GLOBAL SEISMIC NETWORKS
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WWSSN (USGS) and ESSN (USSR and allied countries) since 1960s (Short period & Long period Analog Seismographs)
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IDA (International Deployment Accelerometers, digital systems) since 1970s.
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GDSN (24 bit Digital Broad Band, USGS, FDSN and IRIS), since 1980s.
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GEOSCOPE (French Program) since 1990s.
World Seismicity (1960-2005) and Plate Bounadries Red : Divergent, Yellow : Convergent, Blue : Transform, White : Diffuse
Seismic Wave Propagation of the 2004 Sumatra earthquake www.geol.binghamton.edu/faculty/jones
www.geol.binghamton.edu/faculty/jones Seismic Wave Propagation of the 2004 Sumatra earthquake
2004 Sumatra Earthquake Recorded by the Global Network This was the first Mega thrust event recorded by the GDSN.
Out of 137 GDSN stations, 110 stations recorded the Sumatra Mega thrust event.
88 stations DMC.
provided real time data and were available within two min. through IRIS 351 FDSN stations data were freely available within couple of minutes.
Epicentre: 3.3 N, 96.0 E Depth: 30 km, O.T.: 00h 58m 53s GMT CMT: Thrust faulting, on a gentle 8 deg dipping plane.
Seismic 4.0x10
22 Moment: Mo = N m Comparable to cumulative seismic Moment of all earthquakes during the last decade. Uniform slip ~5m over 1300 from km fault, width 160-240 km assumed in the model.
were
WWSSN seismogram of the 1964 Alaska Mw 9.2 earthquake GSN seismogram of the 2004 Sumatra-Andaman earthquake Mw 9.3
Source Mechanisms of the 2004 and 2005 Earthquake Sequences (Lay et al., 2005)
CMT SOLUTIONS OF THE 2004 SUMATRA EARTHQUAKE SEQUENCE
Location of Digital Broadband stations 2 nd Jan 2006 Legend BB stations RefTek GDSN stations STS-2 HYB STS-1
Band Pass
Seismograms of the 2004 main shock at different BB stations, India
Vertical Acceleration recorded at VISK (2004 Main Shock)
Vertical Acceleration recorded at VISK (2004 Main Shock)
Vertical Acceleration recorded at BLSP, Jan 2 2005 Aftershock
Vertical Acceleration recorded at BLSP, Jan 2 2005 Aftershock
Love Wave Transverse Component Rayleigh wave Band-pass filtered (0.0078-0.00156 Hz) BB trace of 2 nd Jan 2005 (Mw 6.3) at BLSP
Waveform comparison of the 2004 main shock and the 2 nd Jan 2005 aftershock
Moment rate spectrum of the main shock & the aftershock
Sumatra Aftershock Sequence b-value Least Square Fit: b-value=1.32
Maximum Likelihood b-value= 1.34
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-0.08
2 4 6 8 10 12 14 16 18 20
Tim e (sec) Seismograms showing Acceleration, Velocity & Displacement Aftershock Investigation at Port Blair
GSI Temporary Network for Aftershock Investigation
Three component seismograms of an aftershock recorded in Andaman Islands.
Aftershocks Recorded till March 16, 2005
(a) Aftershocks located by the Global Network (USGS) (b) Aftershocks located by the GSI Temporary Network.
Fault plane solutions of the Aftershocks recorded by the GSI Temporary Network
Real Time Seismic and GPS Monitoring Network (Future Plan)
Tide gauge network for Indian Coastline NIOT
40 automated Tide Gauges having real time data communication for East and West coast of India by 2005-2007
Sea Level Monitoring Stations
HF Radar-based Monitoring of Surface Current and Wave
Okha Port Mangalore Gopalpaur Machilipatnam Kalpakkam Nagapatnam Kulachal Koodankulam Port Blair Indira Point
NATIONAL DATA BUOY PROGRAMME
SPAR Buoy
INDIA
DS1 Arabian Sea
Pipavav
SW1
Mumbai
SW2 SW3
Goa Paradip
DS4
Machillipatnam
SW4
Mangalore
NIOT
Chennai
NIOT
SW6 DS2 DS6A DS7 DS7A
Tuticorin
SW5 DS6 OT1 MB11 DS5 MB11 MB12
Bay of Bengal
MB10 DS3 DISCUSS Buoy
Challenges in Forecasting EARTHQUAKES
Microseismicity in NE India
Resistivity Precursor Study in NE India
Resistivity precursor Study (Shillong) ( Kayal and Banerjee, 1988, JGI )
( Arur et al., 1986 )
( Kayal, 1991, PAGEOPH )
( Kayal, 1991, PAGEOPH )
( Kayal, 1991, PAGEOPH )
Kayal, 1991, PAGEOPH
PRECURSOR: EARTHQUAKE SWARM ( 1984 CACHAR EARTHQUAKE, M 5.8 ) ( Gupta, 1987 )
PRECURSOR: EARTHQUAKE SWARM ( 1988 INDO-BURMA EARTHQUAKE, M 7.3 : Predicted ) ( Gupta and Singh, 1989 )
PRECURSOR: RADON CONTENT IN WELL WATER ( 1988 INDO-BURMA EARTHQUAKE, M 7.3 ) JULY AUGUST 1988 ( Kharsiing, A. D., NEC, Pers. Comm. 1988 )
( De and Kayal, 2003, BSSA )
MICROEARTHQUAKE STUDY IN SIKKIM, EASTERN HIMALAYA (De, 2000)
MICROSEISMICITY MAP OF SIKKIM HIMALAYA ( After De and Kayal, 2004 )
Gravity traverse
Gravity Traverse (Repeat Microgravity Measurement) in Skkim Himalaya
5.7
Temporal changes in gravity at selected stations in Gangtok area, Sikkim.