Duration: 2016-2022
The aim of the IPSIN project is to increase the understanding of intraplate earthquakes both in India and Norway by applying advanced techniques to available high quality data sets. We address several important issues of intraplate seismicity such as spatial distribution, models, properties and causes, in selected areas.
Background
Majority of earthquakes occur on the boundaries of tectonic plates referred to as inter plate, but earthquakes also occur within plates, known as intraplate. Intraplate earthquakes have longer recurrence intervals and are not expected to reach magnitudes greater than M~8.5. However, they can have severe consequences for the following reasons: 1) unexpected due to long return periods; 2) more energy release than interplate earthquakes with the same seismic moment; and 3) less attenuation of the seismic waves due to more stable tectonics near their source.
The largest and best-known intraplate earthquake sequence is that of New Madrid, eastern US, that occurred in 1811-12 with estimated magnitudes of M~8. In India, the largest known intraplate earthquake occurred near the town of Bhuj in 2001 with M7.6. The 1993 Latur earthquake of M6.1 is a rare stable continental region (SCR) earthquake, globally the deadliest intraplate earthquake with a death toll of over 10,000. In Norway, an M6.1 earthquake in 2008 was the initiation of an intraplate earthquake sequence in the Storfjorden area, south-eastern Svalbard. In 1819, an earthquake of magnitude 5.9 occurred in the Rana area, northern Norway.
Approach
With available data sets in India and Norway, a thorough characterization of the intraplate / SCR seismicity in a number of regions is feasible. There is a compelling need to improve databases in terms of seismicity, structures and their geological association with earthquake history. Modeling studies based on the data sets can lead to a better appreciation of the mechanics of earthquake genesis and a more realistic seismic hazard assessment of the intraplate regions.
The work is divided into the following tasks:
- Develop improved models
- Build catalogues of improved locations, mechanisms and source parameters
- Compute horizontal strain rates from GPS velocities
- Understanding the mechanism of reservoir triggered seismicity
- Integration and interpretation of results from all the tasks