Policy Update
Urvashi Singhal
Background
Seismological Monitoring is the continuous observation, measurement, and analysis of earthquake-related activities. It typically involves:
- Seismographs/seismometers to detect and record ground motion.
- Data networks to track earthquake location, magnitude, and depth in real time.
- Analysis of seismic waves to understand earthquake patterns, potential hazards, and regional seismicity.
Microzonation is the process of dividing a geographic area into smaller zones based on their seismic hazard potential.
It involves detailed studies of:
- Geology (rock type, soil conditions, faults)
- Seismic history (past earthquakes)
- Geotechnical data (soil amplification, liquefaction risk)
The goal is to produce a microzonation map that shows which parts of an area are more or less vulnerable to earthquake damage. This helps in urban planning, building codes, and disaster risk reduction.
Seismic Microzonation data is produced by the Ministry of Earth Sciences (MoES) through the National Centre for Seismology (NCS) and is based on guidelines framed by MoES.
Seismic Microzonation study is important as it helps to generate inputs for constructing earthquake-risk-resilient buildings/infrastructures/dwellings to reduce and mitigate the impacts of earthquake shaking and for minimising damages to structures and loss of life for safer urban planning.
Seismic observatories of the National Seismic Network have increased from about 150 stations in 2020 to 168 operational observatories till date, with real‑time data reporting via VSAT.
Functioning
Earthquake monitoring on a 24×7 basis through the National Seismological Network (NSN) of 160 stations is the prime activity of the center. A dedicated team maintains NSN to make available real-time data for real-time monitoring of earthquake activity all across the country. The Central Seismological Observatory (CSO) Shillong was established in 1902 as the second observatory in India; it maintains a 20 station network of northeast India, a part of 160 station national network. The center also deployed a temporary network.as and when required for monitoring swarms or aftershock activity near affected regions
Besides earthquake monitoring, NCS is engaged in Seismic Hazard Microzonation (SHM) studies of populous urban centres. ‘Seismic Hazard Microzonation’’ is a process of classifying a region into zones of relatively similar exposure to various earthquake-related effects and has emerged as a major tool towards our efforts for preparedness and mitigation of losses due to earthquakes. NCS has completed microzonation of the Delhi region on a 1:10,000 scale and played a key role in various studies relating to the seismic microzonation of other cities, such as Jabalpur, and Guwahati. Currently, microzonation studies of Chennai, Coimbatore, Bhubaneshwar, and Mangalore are in progress.
NCS provides Earthquake Data and seismicity reports of specific regions to various user agencies such as insurance companies, industrial units, powerhouses, river valley projects, etc., on a payment basis. Seismological data and earthquake-related information are also provided to different agencies dealing with relief and rehabilitation measures, earthquake disaster mitigation and management related matters, seismic zoning, etc.
As part of the systematic archival of historical analogue charts, state-of-the-art facilities have also been established for raster scanning and vector digitisation of seismic analogue charts. These facilities have enabled raster scanning of a lakh of old analogue charts and vector digitisation of significant earthquake waveforms.
In order to generate trained manpower in the field of seismology and allied subjects, NCS organizes training courses/awareness programmes in Seismology and allied subjects at various levels for station operators and scientists of departmental and various non-departmental agencies.
Performance
India’s National Centre for Seismology operates around 160 observatories equipped with digital instruments connected via real-time communication systems. These can normally identify and pinpoint earthquakes of magnitude 3.5 within five to ten minutes and send alerts to the concerned authorities through SMS, email, or mobile applications. These systems provide near-real-time notification of seismic activity and facilitate timely decision-making and response.
Impact
Good seismological monitoring greatly improves public safety by facilitating early warning and quicker emergency response. It also facilitates microzonation studies where local site effects such as amplification, liquefaction, and landslides are delineated and comprehended by furnishing the fundamental seismic recordings for analysis.
Microzonation maps furnish necessary information on site-specific amplification, resonance frequencies, and geological hazards essential for urban planning, retrofitting, and secure construction practices. These researches guide building code decisions, foundation design, and zoning of land use to minimise damage and loss as a result of earthquake occurrences. The Italian case showed generally high correspondence between experimental amplification values and numerical models in bedrock sections. However, differences appeared where soft sediments were encountered, showing the necessity of detailed modelling for difficult geologic conditions.
Way Forward
- Extend and intensify real-time seismic monitoring networks, especially for high-risk urban environments and underserved areas.
- Utilise machine learning and AI algorithms to enhance the efficiency and reliability of event detection and location.
- Increase integration of seismological data more strongly with early-warning systems and urban resilience planning.
- Apply multidisciplinary approaches through the integration of geological, geophysical, geotechnical, and seismological data as being done in some regions of South Asia to increase microzonation precision. For instance, research suggests that applying “micro-, nano-, pico-, and femto-zonation” levels in strategic urban locations should inform resilient design in response to climate change and urbanisation.
- Sophisticated remote-sensing and computing capabilities such as machine learning-based ground motion prediction models (e.g., based on stratigraphic and morphological parameters) can effectively produce hazard maps for extensive regions.
- Implement multi-criteria decision-making, GIS-based AHP (Analytic Hierarchy Process) and other statistical methods to assist in consolidating various hazard factors for South Asian cities such as Guwahati, Chennai, Kolkata, and others.
- Strengthen codes and regulations, integrating microzonation findings into official building codes, and land-use planning procedures like Italian guidelines will guarantee long-term resilience.
References
About the contributor
Urvashi Singhal is a master’s student at DTU, simultaneously pursuing actuarial science. She is currently working as a research intern on an ICSSR project focused on menstrual leave policy.
Acknowledgment: The author sincerely thanks the IMPRI team for their valuable support.
Disclaimer: All views expressed in the article belong solely to the author and not necessarily to the organisation.
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