Long-term earthquake monitoring and seismic-hazard assessment

The BGS has pioneered long-term seismic monitoring in the UK and research in seismic-hazard assessment. The earthquake seismology team rapidly analyses data to provide objective information on significant seismic events around the clock, helping to allay public concern and support the appropriate emergency response. Rapid access to information has helped to minimise economic losses and develop safe operating practices in industry. The work on seismic-hazard assessment has helped inform regulatory decisions and the setting of appropriate guidelines for engineering in high-consequence industries such as the nuclear, water and hydro-electric industries. Improved models of seismic hazard have had cost benefits in the construction of critical facilities.

Background

image to be added.

Although seismic hazard and risk in the UK are low by world standards, there are numerous examples of earthquakes that have caused moderate damage and widespread public alarm (e.g. Folkestone, 2007) particularly when they have occurred in densely populated areas (e.g. Manchester, 2002; Dudley, 2002) or affected large areas (Market Rasen, 2008). Objective information is essential to allay concern, to coordinate an appropriate emergency response and to plan for future events. Earthquake activity is also at a level that could pose a potential threat to sensitive structures such as nuclear facilities, chemical plants and dams. This work is supported by NERC National Capability funding (1991–present) with additional funding from private- and public-sector partners.

Long-term seismic monitoring and hazard modelling at the BGS

image to be added.

We began installing seismograph stations in the UK in the late 1960s and over the next thirty years the network grew in size, reaching a peak of 146 stations by the late nineties. In 2005, we started the development of a network of broadband seismograph stations across the UK to provide high-quality, near real-time data for monitoring and research. Development of unique stochastic modelling software for probabilistic seismic-hazard assessments (PSHA) began in the late 1990s. This has continued to be developed and is used for modelling seismic hazard at numerous sites around the world.

Industry, UK Government and the public are concerned about the hazard posed by earthquakes and the immediate effects of felt or damaging vibrations on people and structures. The BGS is the sole provider of UK-wide capability in the detection and measurement of earthquake activity and provides a constant, near real-time response to significant earthquakes, as well as developing methodologies for seismic-hazard assessment. We have expertise in seismic data processing, analysis and interpretation, including near real-time determination of earthquake parameters (location, time and magnitude) and we are recognised internationally as an authority on seismic hazard through our involvement in numerous seismic-hazard projects in the UK and overseas.

Importance of long-term, near real-time seismic monitoring to the UK

image to be added.

Among the beneficiaries of long-term seismic monitoring are:

Near real-time information helps the nuclear and water industry operators rapidly identify false alarms, react appropriately, and minimise potential economic losses resulting from unnecessary and costly shutdown procedures for inspections of plant. Continuous long-term monitoring and improved assessments of seismic hazard in the UK by the BGS has helped inform regulatory decisions in the nuclear industry, where the consequences of failure are severe and reliable hazard assessment is critical. Greater understanding of uncertainties and the development of improved models for seismic-hazard estimates have also resulted in reduced engineering conservatism, leading to significant cost benefits when constructing nuclear facilities, chemical plants and dams.

Examples

The BGS routinely undertakes commercial seismic-hazard work for engineering projects in the public and private sectors all around the world, which has a significant impact on construction methods and operating procedures.

  • Continuous monitoring and reporting of significant earthquakes in the UK and immediate offshore area over the last 20 years. For example, the Folkestone earthquake of 28 April 2007 resulted in emergency measures being taken by local authorities, power outages, transport disruptions and localised damage of a severity not seen in the UK in at least 50 years. BGS was able to provide rapid source parameters and expected ground shaking for the earthquake. This information was used to avoid costly shutdown of the nearby Dungeness Nuclear Power Station and the Channel Tunnel.
  • BGS has provided both data and scientific expertise to assess the hazards from induced earthquakes resulting from shale gas exploration and production, and helped inform regulatory decisions taken by DECC in 2012 on hydraulic fracturing operations.
  • BGS contributed to the public enquiry following the Buncefield Explosion providing evidence helping to constrain the timing and size of the explosion. The Buncefield Incident, 11 December 2005: The final report of the Major Incident Investigation Board (2008)
  • Reports commissioned by Defra into tsunami hazard in the UK (2005 and 2006) led to later work on establishing the seismic component of an early warning system and informed for consideration (by Government) on the UK role in the Intergovernmental Oceanographic Commission of UNESCO North-eastern Atlantic, the Mediterranean and connected seas Tsunami Warning System (NEAMTWS).
  • BGS participated in COBRA/SAGE meetings convened after the Tohoku earthquake in Japan, March 2011, advising on aftershock probabilities and estimated ground motions around the Fukushima Nuclear Power Station.
  • BGS provides information and expertise on earthquakes to the Natural Hazards Partnership).

Contact

Brian Baptie: head of earthquake seismology

David Kerridge: director of NERC Geophysical and Geodetic Services and Facilities

John Rees: science director, earth hazards and observatories

Publications

Near real–time earthquake

BGS earthquakes

Sargeant, S. 2008. Things That Go Bump in the Night, Planet Earth

http://planetearth.nerc.ac.uk/features/story.aspx?id=177

Baptie, B. 2011. Could It Happen Here? SECED Newsletter, 23, 1

http://www.seced.org.uk/index.php/newsletters/35-seced-newsletter-vol-23-no-1

Science in the Dock, Material World BBC Radio 4, 25/10/2012

http://www.bbc.co.uk/programmes/b01ngnwg

Musson, R. 2009. How to map an earthquake. Mapping News (35). 24–25.

http://nora.nerc.ac.uk/7165/