Wednesday, March 21, 2018

Warning and forecasting of Earthquakes

Warning and forecasting of Earthquakes

The Ministry of Earth System Science - National Centre for Seismology (MoES-NCS) maintains a national seismological network consisting of 42 digital seismographs stations to measure earthquake magnitude and monitor earthquake activity in and around the Indian region. Additionally 78 new digital seismographs have been installed recently. The ground motion data recorded by the instrument system are used for the estimation of magnitude and other earthquake parameters. However, there is no scientific technique available anywhere in the world to forecast or predict the occurrence of earthquake with reasonable degree of accuracy  with regard to space, time and magnitude.
Loss of life and damage to property due to earthquakes could be reduced through proper planning and implementation of pre- and post- disaster preparedness and management strategies by the government. Guidelines have been published by the Bureau of Indian Standards (BIS) and Building Materials and Technology Promotion Council (BMTPC) for the design of earthquake resistant structures to minimise the loss of life and damage to property caused by earthquakes. Government agencies and academic institutions are currently engaged in the following activities for warning and forecasting earthquakes.
  • Up-gradation and digitization of topographic maps with contour interval of 0.5m by Survey of India (SOI) and National Remote Sensing Centre (NRSC)
  • Sharing of seismic data being collected by IMD with other departments
  • Deployment and augmentation of observing systems such as GPS, bore hole sensors, multi-parametric observing systems, etc at identified locations for better understanding of physical processes associated with earthquakes, active fault mapping in addition to the existing conventional weak and strong motion observing systems.
  • Creation of a modern test and maintenance facility for testing and upkeep or rectification of existing sophisticated equipment and seismological instruments such as broadband sensors, SMAs, digitizers and communication systems.
  • Strengthening or augmentation of the existing data centre facility of IMD.
  • Raster scanning and vector digitization of seismic analog charts at seismological observatory. Raster scanning of remaining significant historical seismograms, their vector digitization and archival in electronic media.
  • Analysis of seismological and collateral geophysical data in near real-time
  • R & D programs in collaboration with other leading countries in development of earthquake prediction and forecasting methods.
  • Establishment of additional heavy mass vibration laboratories
  • Development of GIS based hazard and vulnerability database or digitized maps
  • Innovative earthquake resistant construction technologies for new and retrofitting of existing buildings
  • Monitoring earthquakes and conducting research for earthquake instrumentation
  • Real-time monitoring for occurrence of earthquakes
  • Setting-up earthquake scenarios for major urban high hazard areas
  • Mapping of all faults
Earthquake instrumentation and monitoring:
India has more than two hundred earthquake monitoring stations which are mainly located in high hazard areas along the Himalayas and in the north-east. In order to identify the major earthquake sources and their activity rates, dense networks of earthquake monitoring stations are required. Each such network consists of at least 90 strong motion instruments and 10 broad band instruments. These instruments are used to identify the seismic source, activity rate, strain build-up, determination of ground motion equations and for updating earthquake hazard map of the region.

Real-time earthquake occurrence monitoring:
A network of earthquake monitoring stations is used to assess the size, location, depth and wave propagation parameters of earthquake events in realtime.

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