Coordinator: Dr. Mala Bagiya
Team members : Dr. S. Pandey, Dr. Rabin Das +
Introduction
Geohazards are events coupled to geological and geophysical processes, which can potentially cause damage to the environment and pose serious danger to society. Geohazards can be small features and at times can attain huge dimensions and affect local and regional socio-economics to a large extent. Understanding potential interlinkages between different aspects of geohazards is key to mitigate the socio economy effects and human sufferings.
Seismicity is one of the potential sources that can affect the lithosphere-atmosphere- ionosphere system at different scales prior to, during or after an earthquake occurrence. Indian Institute of Geomagnetism (IIG) is investigating various aspects of major Geohazards with a multi-disciplinary approach using land and space based geophysical techniques.
Earthquake Seismology, Magnetotelluric (MT) monitoring techniques, Geodetic measurement using GPS and InSAR and monitoring of atmosphere-ionosphere system including radio instruments are core geophysical techniques being used by the Geohazard group, which can clearly indicate where potential Geohazard concerns exist.
Earthquake seismology deals with subsurface velocity structure, source characterization, seismic hazard evaluation, attenuation characteristics, seismic risk analysis,earthquake tomography and seismotectonic. Currently, IIG is running a network of eleven broadband seismometers in the NE Indian region.
Use of Magnetotelluric monitoring experiments in diverse Geohazard environment (seismically active region, hydrothermal system, dam safety, cavities and sinkholeetc.) aim to observe the associated electrical conductivity changes as a result of changes in fluid composition, heat source and stress-induced structural changes. Stationary MT network is deployed in the NE Indian region for monitoring neotectonic activities.
Geodetic technique deals with crustal deformation, strain distribution, crustal displacements. Atmospheric-Ionospheric measurements may allow to decipher the energy cross talk between ground and space during a hazard event. Co-seismic ionospheric disturbances have been investigated in detail and are reasonably well understood.An attempt to develop tsunami early warning based on ionospheric measurements is in progress.
Activities of the Geohazard Group:
• Earthquake Monitoring
• Seismic hazard assessment
• Seismic risk analysis
• Ionospheric Seismology
• Geoelectrical characterization
• Structure and Evolution of the Tectonosphere
• Magnetotelluric Monitoring experiments
• Crustal deformation
• Tsunami assessment & Early Warning System
Significance of this Research
Predicting Geohazards is not feasible yet. However, risk reduction/mitigation measures are important to reduce the devastating impacts of Geohazard on communities. Understanding the causes and mechanisms of natural disasters and potential inter linkages between different aspects of geohazards is key to mitigate the socio economy effects and human sufferings. Various aspects of major geohazards with a multi-disciplinary approach using land and space based geophysical techniques are being examined by the GHG at IIG.
The ongoing studies will enable us to develop an early warning system about the Geohazard events and its timely dissemination will help mitigate the human misery.
Instruments and locations
Campaign mode, time-lapse and monitoring experiment are run with the following equipments as per survey objectives:
Instruments in use
1. GPS & GNSS receivers.
2. Broadband Seismometers (STS2.5, REFTEK151 and Trillium240 with REFTEK130S data loggers)
3. Magnetotelluric equipments (MTU5A, MTU-RT & MTU-5C) for campaign mode and monitoring experiments.
4. Resistivity Imaging system (Syscal Pro 48 switch)
5. Radon monitors
6. Atmospheric Electric Field Monitors
7. Automatic Weather Station (AWS)
Contact details
Prof. A. K. Singh
ajaykishore[dot]s[at]iigm[dot]res[dot]in
