Co-seismic and post-seismic displacements in Andaman and Nicobar Islands from GPS measurements
IR@C-MMACS: CSIR-Centre for Mathematical Modelling and Computer Simulation, Bangalore
View Archive Info| Field | Value | |
| Title |
Co-seismic and post-seismic
displacements in Andaman and Nicobar
Islands from GPS measurements
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| Creator |
Jade, Sridevi
M B, Ananda P, Dileep Kumar |
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| Subject |
GNSS/GPS Geodesy
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| Description |
We calculate the displacements of four sites in Andaman
and Nicobar islands from Diglipur (13.16N) to Car Nicobar
(9.22N), using GPS measurements made at these sites
in September 2003 and repeated in February 2005, assuming
that the inter-seismic displacements at all these
sites can be represented by the 14 2 mm/yr convergence
between CARI near Port Blair and Bangalore,
reported earlier on the basis of GPS measurements
made by us between 1996 and 1999. Since the latest
measurements were made after about a month of the
great Sumatra event of 26 December 2004, and several
moderate earthquake ruptures had since occurred
adding to the co-seismic surface displacements, the values
reported here also represent the contributions of aftershocks.
Rigorous analysis of the two epoch GPS datasets
from these sites yields precise displacement vectors,
among which the one at Car Nicobar has the largest
horizontal magnitude (6.49 0.009 m to the WSW)
with a significant 1.1 m subsidence. The horizontal displacement
at Chatham Island near Port Blair is also
similarly oriented, but smaller (3.53 0.010 m) with
reduced subsidence. Further northeast of Port Blair,
the Havelock Island site shows an even smaller horizontal displacement (1.6 0.013 m) to SW and nothing significant in the vertical while Diglipur, the northernmost
Andaman site shows a much larger horizontal displacement
(4.78 0.008 m) to the SW, and a significant
uplift of ~0.6 m. While these results are broadly consistent
with the largely thrust component of earthquake
fault slips reported by several workers on the basis of
seismic fault mechanism studies, the southern components
in the displacements of the northern sites require
significant dextral slip contributions that may have
been made by some of the moderate aftershocks or by
slower ones or by aseismic strike-slip movements along
the northern subduction boundary.
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| Publisher |
Indian Academy of Sciences
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| Date |
2005-06-25
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| Type |
Article
PeerReviewed |
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| Format |
application/pdf
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| Identifier |
http://cir.cmmacs.ernet.in/133/1/currsci05.pdf
Jade, Sridevi and M B, Ananda and P, Dileep Kumar (2005) Co-seismic and post-seismic displacements in Andaman and Nicobar Islands from GPS measurements. Current Sciences , 88 (12). pp. 1980-1984. |
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| Relation |
http://www.ias.ac.in/currsci
http://cir.cmmacs.ernet.in/133/ |
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