Annual Report 2000-2001

Scientific Research

Seismicity Programme

The Seismicity Programme has been evolved with a view to understand the earthquake processes/mechanism related to the Indian Lithosphere, their recurrence interval and their manifestation on the surface towards developing knowledge and techniques for hazard mitigation. During the last few years, a good infrastructure has been created at various identified locations and lab facilities have been established at different institutions. New groups, especially from Northeast were infused to take up the earthquake related studies. With the increased interest of the scientific community in the programme, new geographical areas like Delhi region, Bihar plains and peninsular shield were also taken up for carrying out integrated studies. Special initiatives were launched for Northeast region and Modern seismological observations have been set up at selected locations.

Ongoing Activities

The strong motion Array of Delhi region has generated a good data set on Chamoli earthquake. The data have been used to carry out a study for prediction of ground motion in Delhi due to future large earthquakes in Chamoli region. Strong motion data, generated from the Himalaya region, have also been used for designing earthquake resistant structures. Most of the Broadband observatories, established under World Bank Project, in peninsular region have become operational. Under a project entitled" Imaging of seismic faults in Killari and adjoining region of Maharashtra, a seismological observatory is being set up at Nanded. Efforts are being made to instrument a few selected buildings in Delhi to get data on the structural response behavior and soil characteristics. The data so generated will be of great value for design of structures.

A project database, established at WIHG, Dehradun has started functioning. In addition, a modern telemetered seismic system has been set up at Tejpur, Assam with the support from DST to NGRI. A TL dating facility has also been set up at Manipur University. A project on "Upgradation and modernization of Shake Table Facility at Department of Earthquake Engineering", University of Roorkee is being implemented. The facility will help in earthquake disaster mitigation research related studies.

A project has been sanctioned to National Informatics Centre Services Inc. (NICSI), New Delhi to link the seismological observatories and National Seismological Data Centre (NSDC), IMD through V-SATs. The project is being implemented in close coordination with IMD and NICSI. Indigenous development of of geo-instrumentation has also been initiated. In this direction, a project was sanctioned to CSIO, Chandigarh to design and develop 16-bit and 20-24 bit seismographs. Also, a proposal to design and develop a multi-element telemetry system at Bhabha Atomic Research Centre for Koyna region is under consideration.

Two state-of-art seismic telemetry systems, procured for Khandwa and Koyna-Warna region, are under testing and will be installed shortly.

Achievements under the completed projects

• In a project entitled "Seismic Hazard in the Himalayas and North-East India Regions", following achievements have been reported:
  
  Moment magnitude catalogs have been complied for the different time periods and magnitude ranges for the Himalaya and Northeast India (areas covering longitude 69-830 E & latitude 25-360 ) as detailed below:
• Catalog of large earthquakes for the period 1762-1999.
• Catalog of moderate earthquakes for the period 1950-1999.
• Catalog of small earthquakes for the period 1964-1999.

From the above catalogs frequency-magnitude relationship has been established.
It has been reported that there is a Quiescence of Major earthquakes since 1952.
Also it has been concluded that the Wadati-Benioff Zone has a predominant down-dip tensional stress regime and the subduction in the Indo-Burma region is possibly active.

• In a project entitled "Estimation of Moment Rate Function in Himalayas and Koyna Regions using Empirical Green's Function" Source time functions of selected events has been estimated as empirical Green's functions. The source time function for the Koyna events (M=3.1) appears to be unipolar Pulse, while for Chamoli event (M=6.5) it is relatively simpler and represent simple rupture process as expected from the rupture of earthquake of such size.
  
• The project entitled "Neotectonic and Palaeoseismic Studies in Katchchh and adojoining Areas" provides information for better understanding of tectonic aspects of Kachchh Mainland. Following are the specific achievements:
  • The Karol Hill Fault Zone (KHFZ) has experienced at least three major events of uplifts, one coinciding with the inversion event, which resulted in the large-scale drainage reversal and other, two post dating it. Also, chronology of the later is inferred on the basis that three individual paired terraces are carved in early Pleistocene miliolite rocks exposed within the KHFZ.
    
  • The morphometric analysis of the KHFZ shows that Krol Hill Fault is one of the most active faults in the Kachchh region.
    
  • Studies related to the genesis of Allah indicate that the faulting involved was of normal nature.
    
  • The seismic hazard analysis indicates the presence of four major seismo-active zones in Kachchh region.
• In a project entitled "Active tectonics of the Western Gangetic Plains including the Piedmont Zone" following achievements have been reported.
  • Four major types of landforms - Aeolian Plain, Piedmont, Plains associated with rivers and Interfluves are identified from the area.
    
  • A soil chronoassociation with five QGN1 -QGN5 with ages of < 500 years, > 500 years, 2.5 ka, ~5 ka and 8.5 ka respectively has been recognized from the study.
    
  • Four tectonic blocks i.e. Solani, Khoh, Solani-Ganga, Upper Ganga-Yamuna, Lower Ganga-Yamuna and Ganga-Ramganga blocks are deciphered.
    
  • Using a soil-geomorphic approach developed at UOR, significant neotectonic movements have been inferred. For example- (i) uplift of Lower Ganga-Yamuna, Ganga-Ramganga and Upper Ganga-yamuna blocks took place at about 8.5 ka, 5 ka and 2.5 ka respectively, (Ii) Westward tilting of the Ganga-Ramganga block took place at about 2.0 ka (?) and 1 ka leading to shifting of the Ganga river in the same direction (iii) these dates give a recurrence interval of 1000-3500 years for major movements in the area.
    
  • A cold and dry climate prevailed in the area from early Holocene to about 6000 B.P. and resulted in accumulation of pedogenic salt and calcrete in the soil. Later a warm and water climate accompanied by improved drainage caused leaching down of salts and calcrete from the soil in certain areas.

New Initiatives

Setting up of Earthquake Risk Evaluation Centre (EREC)

A proposal to establish an Earthquake Risk Evaluation Centre (EREC) in Northern India has been approved by the Committee of Secretaries (COS) at its meeting held on September 19th, 2000. The EREC will primarily concentrate its activities in northern India, which is contiguous to the Himalaya and forms a part of global seismic belt. The fast population growth, changing land use/land cover and economic development in the Himalaya and its contiguous region demands, a very focussed attention.

The Centre will undertake/promote all tasks related to earthquake risk evaluation. The specific outputs are

• To provide earthquake risk related knowledge products for designated areas: earthquake hazard, vulnerability as well as risk maps and figures.
  
• To develop suitably distributed Information Systems for ready collation of primary data from different national sources, their archival, availability and retrieval, their quality indices, and also develop advance level integrated databases.
  
• To develop a vibrant user Interface in order to constantly interact with various agencies involved in risk mitigation as well as with local communities with the express objective of a) communicating to them the knowledge products of the centre and their implications, and b) to continually reappraise the relevance and usability of these products, through specially designed feedback activities.
  
• To articulate well considered legislative and regulatory measures for effective mitigation of risk, and advise/request appropriate agencies to implement these.
  
• To catalyze development of evermore-effective risk assessment and mitigation approaches and systems by sponsoring such programs that may be warranted in the light of new emerging national priorities as well as new developments globally in exploiting up-to-date S & T systems towards mitigation.

An Indo-Italian Workshop on "Seismic Risk Evaluation - Methodology and applications" is being organized at NGRI, Hyderabad. The over all idea of this workshop is to identify certain collaborative projects of mutual interest in the field of seismic risk evaluation. The workshop also includes a field visit to Jabalpur, which has been identified for carrying out a sample survey for microzonation studies.

Under the Jai Vigyan Technology Mission project on Natural Hazard Assessment in Himalaya, activities have been initiated to set up the Geophysical Research Laboratory (GRL), Allahabad.

A special volume on seismicity, containing the research papers emanated from the various DST supported projects is being published through Indian Geological Congress.

The first issue of the newsletter containing scientific developments taking place globally and also contributions from the projects supported under the programme has been brought out.

Short Term Courses/Workshop

• An international workshop on "Seismic Electromagnetics and Space Sciences" was organized at R.B.S. College, Agra during Dec. 19-21, 2000. About 90 participants from India and abroad participated.
  
• A training course is being organized on "Broad Band Seismographs" at India Meteorological Department, New Delhi. About 30 participants, from the institutions/universities, engaged in operation and maintenance of BB observatories are expected to attend.
  
• A training course on "operation and maintenance of strong motion instruments" is being organized at Department of Earthquake Engineering, University of Roorkee, Roorkee. About 20 participants, from different organizations, are expected to attend the course.