TECTONIC STUDY AROUND INDORE (CENTRAL INDIA) WITH EMPHASIS ON SEISMOLOGY
USING VISUAL & DIGITAL IMAGE PROCESSING TECHNIQUES
Soni S.K.
Reader in Remote Sensing, Department of Civil Engineering,
Shri G.S. Institute of Technology & Science, Indore (MP), India.
ABSTRACT
In the recent past, region in and around Indore forms one of the interesting seismie zone. in August 1982
till December 1982, about 50 shoeks lasting till five seconds approximately were felt. In October 1990, similar
shocks were felt but their time duration and intensity of shocks was more. Geologically, Indore is part of
Deccan trap basalts having different sets of joints, additionally, 60 Kms. away from Indore river Narmada
flows in a rift zone flanked with faults & fractures. Geomorphologieal & quaternary geological studies have
indieated that the area is teetonieally disturbed.
In the recent studies, the author has used Landsat TM and IRS LISS II data to prepare the lineament map
using visual & digital image processing techniques. Statistical analysis has been carried out and the results
have been interpreted emphasizing the tectonic origin of the structure lineaments. From the results obtained
so far, it is difficult to conclude the exact cause for the origin and cause of the shock waves, but only infe-
rences could be drawn presently. Looking to the tectonic set up, the author feels this may be due to normal
faulting and fold axis which give rise to wedging under tension, as the area under study lies just above Narmada
Tapti Rift and there is also Aravalli axis of folding which takes turn near the study area continue further
to meet the Aravalli strike. The author is also of the opinion that such tremors may be due to slicken side
effects in black cotton soil or the presence of vertical, angular, horizontal and columnar joints. The author
also feels that such shocks can be attributed to voleanic phenomenon.
KEYWORDS
TECTONIC, INDORE, SEISMOLOGY, REMOTE SENSING, STRUCTURAL ANALYSIS.
1. INTRODUCTION ments.
Data on earth quake occurrence, geological and 3. REVIEW
tectonic set up of the area and evidences of move-
ments in geological recent times are utilized to 3.1 Tectonic Evaluation in Relation to Seismology
identify seismotectonic lineaments capable of gene- of India
rating an earthquake. No unique methodology
has so far been evolved to account for all the The tectonic evaluation of the earth's crust in
uncertainties in geological data for estimating India has been done in two main stages
earthquake probailities and evaluation of seismic
risk for practical applications. Greater reliance i. Geosynelinal stage.
is thus made on earthquake occurrence and strong ii. Platform stage.
ground motion records for prediction of ground
motion with the assumption that same pattern 3.2 Geosynclinal Stage
of earthquake will be valid for the future. In
case some seismological data is meagre or not Tectonic classification of aterritary by the age
available, extrapolation of information from regions of main folding that completes the geosynelinal
of past earthquake to potential source of regions development is a well known principle outlined
in the vicinity of the site is attempted for the by Argand (1924), Arkhangeloky (1941) and Shastky
evaluation of ground motion. (1960). Five folded regions constituting the base-
ment of the Indian platform could be distinguished
On August 15, 1982, people living in Joshi Guradia in Indian peninsula. They are five folded regions
situated about 18 Kms. from Indore have felt constituting the basement of Indian platform.
ground shocks lasting for about 2 seconds. The They are
maximum duration of shocks was about 5 seconds.
About 50 shocks were felt till December 1982. i. Dharwar folding.
Occurrence of siumilar shoeks was also reported ii. — Aravalli folding.
at village Datoda about 5 Kms. west of Joshi iii. Eastern Ghat folding.
Guradia. An important observation made by the iv. Satpura folding.
author was that the Village Shiv Nagar situated v. Delhi folding (Krishnan 1953 and Narayan
2 Kms. north of Joshi Guradia and Tincha 1 Km. Swami 1966-a).
south of Joshi Guradia was devoid of this activity.
On October 6, 1990, occurrence of similar shocks 3.3 Platform Stage
was reported from Village Machal 20 Kms. west
of Indore. Here, the intensity of shocks was more The platform stage of evolution begins with the
as compared to the earlier one. consolidation of geosynelinal areas to form the
basement of platform. The Indian platform is
2. OBJECTIVE characterized by the folded basement of Archaean
and Proterotoie rocks. A number of sedimentary
In the present study, the author has used Landsat basins forms the parts of Indian platform.
MSS TM and IRS LISS II data to prepare the linea-
ment maps using visual & digital image processing Tectonic evolution of the Indian platform has
techniques. Statistical analysis has also been attemp- been traced through the six sedimentary covers
ted and the results have been interpreted empha- of the platform. Each of these sequences limited
sizing the tectonic origin of the structural linea- by pronounced unconformities of wider extent
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