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J R Kayal Formerly: Head (Gepphysics), Geol Surv India
CSIR Emeritus Scientist, Jadavpur University, Kolkata& Adjunct Professor, Indian School of Mines, Dhanbad
Seismic Environments in Northeast India Region: An Appraisal
1997
19931967
Tibet
India
Kyona Killari
JabalpurBhuj
Large and Great Earthquakes in Indian Sub-continent
Kayal, 2008
IMD, 2005
Earthquakes at the Burma-Andaman-Sumatra-Java Subduction Zone
Rao et al., 2006
Tectonic Map of Northeast India Region
Kayal et al., 2006
Isoseismal map of the 1897 great Shillong Earthquake (Oldham, 1899)
Picture showing the up thrown boulders (Oldham, 1899).
Kayal, 2010, GNHR
(a) Isoseismal map of the 1950 Assam Great earthquakeTandon, 1954).
Inset: Damaged bridge in the maximum Intensity zone (Poddar, 1950).
(b) Fault plane solutions of the earthquakes in the Assam syntaxis zone (Holt et al.,1991)
Kayal, 2010, GNHR
Tectonic Evolution in NE India Region
Nandy, 2001
Regional Seismicity (1964-96) in NE India Region
Data source : USGS, 1964-1996
Kayal, 1998, J Geophys
Gravity Map of Northeast India Region
Kayal, 1998, J Geophys
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
0 100 200
Depth (Km)
Lat
itu
de
ArunachalPradesh
Upper Assam
Nagaland
Manipur
Mizoram(Eastern)
Bagan(Myanmar)
Irrawaddy(Myanmar)
(b)
Sanoujam, Kayal, Arefiev et al., 2009
EHB relocated events: 1980-2007
0
50
100
150
200
90 91 92 93 94 95 96 97 98 99 100
Zone C
Kopili Fault Naga Thrust CBB
0
50
100
150
200
90 91 92 93 94 95 96 97 98 99 100
Zone B
Sagaing Fault
0
50
100
150
200
90 91 92 93 94 95 96 97 98 99 100
Zone D
Meghalaya EBT Sagaing Fault
0
50
100
150
200
90 91 92 93 94 95 96 97 98 99 100
Zone E
Sagaing FaultBangladesh
0
50
100
150
200
90 91 92 93 94 95 96 97 98 99 100
Zone G
0
50
100
150
200
90 91 92 93 94 95 96 97 98 99 100
0
Zone F
Mizoram
0
50
100
150
200
90 91 92 93 94 95 96 97 98 99 100
Zone A
A
B
C
D
E
F
G
CBB
CBB
CBB
CMT
EBT
Sagaing Fault
Sagaing Fault
Sagaing Fault
Section parallel to Lohit & Mishmi thrusts
Sagu (Myanmar)
Sanoujam, Kayal, Arefiev et al., 2009
Degree East
Degree North
Sanjoum, Kayal, Arefiev et al., 2009
3D view of the Subduction zone below IBR
Rao & Kalpana, 2005, GRL
Subduction Tectonics: Indo Burma range
Microseismicity Map of Northeast India: Local Network Data (1982-1992)
Kayal, 2008
Microseismicity recorded by local networks (RRL-J/NGRI Bulletin 1993-1999)
Bhattacharya & Kayal 2002
Microseismicity Map of NE India (1993-99)
(Bhattacharya & Kayal, 2002
b-value Mapping in Shillong Plateau Region (1993-99)
9 0 . 5 9 1 9 1 . 5 9 2 9 2 . 5 9 3 9 3 . 5 9 4 9 4 . 52 5
2 5 . 5
2 6
2 6 . 5
2 7
2 7 . 5
2 8
0 . 3
0 . 4
0 . 5
0 . 6
0 . 7
0 . 8
0 . 9
1
K o p i l i L i n e a me n t
S h i l l o n g P l a t e a u
U p p e r A s s a m V a l l e y
Bhattacharya & Kayal, 2002
Fractal Dimension Mapping in Shillong Plateau Region (1993-99)
9 0 . 5 9 1 9 1 . 5 9 2 9 2 . 5 9 3 9 3 . 5 9 4 9 4 . 52 5
2 5 . 5
2 6
2 6 . 5
2 7
2 7 . 5
2 8
0 . 8
1
1 . 2
1 . 4
1 . 6
1 . 8
K o p i l i L i n e a me n t
S h i l l o n g P l a t e a u
U p p e r A s s a m V a l l e y
Bhattacharya & Kayal, 2002
2~)( DrrC
Seismic Images beneath the Shillong Plateau Region (1993-99)
(Bhattacharya & Kayal et al., 2007, AJES)
9 1 9 2 9 3 9 4 9 5
2 4
2 5
2 6
2 7
2 89 1 9 2 9 3 9 4 9 5
2 5
2 6
2 7
2 4
2 8
[ 5 - 1 5 k m ] [ 1 5 - 2 5 k m ]
[ 2 5 - 3 5 k m ] [ 3 5 - 4 5 k m ]
[ 1 0 k m ] [ 2 0 k m ]
[ 3 0 k m ] [ 4 0 k m ]
+ 1 5 %
- 1 5 %
0
M H
M B T
MC T
D F
D T
N T
S P
M H
KL
D F
S P
M H
M B T
M C T
D F
D T
N T
S P
M HKL
M B T
MC T
D F
D T
N T
S P
KL
+ 2 0 %
- 2 0 %
0
+ 5 %
+ 5 %
Pop-up Tectonic Model: Shillong Plateau
(Kayal et al, 2006, Curr Sci.)
(Bilham & England, 2001, Nature)
Fault plane solutions of recent earthquakes (2000-2009)
Kayal, Arefiev, Dorbath et al., 2011 (submitted).
(a) Pop-up Tectonic Model, Bilham & England, 2001
(b) Depth section of the events across the Shillong Plateau
© The fault planes at depth
Kayal, Arefiev, Dorbath et al., 2011 (submitted)
Transverse Tectonics along the Kopili fault
Kayal, Arefiev, Dorbath et al., 2011(submitted)
Paleoseismic Evidences at the Epicentre Zone: 1897 Shillong Earthquake
(Sukhija et al., 1999, Tectonophys)Recurrence period : 500 + 100 yrs
Kayal , Arefiev et al., 2010, GNHR
Recent Two Felt Earthqukes in NE India Region
Kayal , Arefiev et al., 2010, GNHR
The Two Recent Felt EQs on the Kopili Fault
Assam Valley EQ: Mw 5.4Aug 19, 2009
& Bhutan Him EQ: Mw 6.3Sept 21, 2009
Teleseismic stations used for Moment Tensor solutions
THANK YOU !
Tista River, Sikkim Himalaya