| Session Details | |
| Section | SE - Solid Earth Sciences |
| Session Title | Seismogenesis of Large Intraplate Earthquakes Occurring in Strong Continental Crust |
| Main Convener | Dr. Prantik Mandal (NGRI (CSIR), Hyderabad, India) |
| Co-convener(s) | Prof. Jnana Ranjan Kayal (Jadavpur University, India) |
| Session Description | Earthquakes have struck stable plate interior at a number of locations, including the New Madrid zone (Mw 7.8, 1811-12), United States; Tennant Creek (Ms 6.7, 1988), Australia; Ungava (Ms 6.3, 1989), Canada; and Latur (Mw 6.3,1993), Jabalpur (Mw 5.8, 1997) and Bhuj (Mw 7.7, 2001), India. Among these, only the New Madrid and Kachchh (Bhuj) regions have the distinction of having stable continental region events of magnitude nearing 8.0. These earthquakes are rare which account for only 0.5% of total annual seismic energy released globally. Large intraplate continental earthquakes like the 1811-12 New Madrid (Mw ³ 8.0) and the 2001 Bhuj (Mw 7.7) were highly destructive because they occurred in shield areas and their seismogenesis is not well understood. It is enigmatic that such large strain can accumulate in a region away from active plate boundaries. Generation of these earthquakes in the upper crust have been attributed to the sudden movement along the pre-existing weak zones due to local stress perturbation either/or resulted from the regional plate boundary forces, surface as well as subsurface loading, reservoir loading, presence of fluids and intersection of crustal weak zones. However, the intermediate to deep crustal earthquakes of moderate-to-large magnitudes have occurred in several continental rift zones like Amazonian (Brazil), East African (Africa), Baikal (Russia), Rio-grande (North America), Narmada (India) and Reelfoot (New-Madrid, USA), which have been explained in terms of failure of old rift due to local stress perturbations associated with substantial crustal as well as astheonspheric thinning, intruded magmatic material from the underlying mantle and deepening of the brittle-ductile transition depth. Since recent years, the rapid development of theoretical and numerical tools has led to several possible models for explaining the occurrence of large intraplate earthquakes. The recent occurrences of large intraplate earthquakes have caused substantial damages and deaths due to the growing population and poor constructions. However, in comparison, in most of the developing countries/regions with high seismic activity and earthquake disasters, there is still lack of enough understanding regarding the seismo-genesis of devastating intraplate earthquakes. Modeling of source processes, observations and earthquake hazard associated with large intraplate earthquakes in these regions are very much needed for the safety of society with the threatening of earthquake disasters. Meeting these dual challenges is one of the tasks of seismological and engineering communities in the coming decade. To reflect the up-to-date advancements in modeling of source processes and earthquake hazard associated with intraplate earthquakes, and to foster inter-disciplinary international exchange and cooperation in these fields, this session will be focusing on, but not limited to, the following topics: 1) Seismogenesis of devastating intraplate earthquakes, 2) Evaluation of seismic hazards associated with the large intraplate earthquakes, 3) Study of source scaling of intraplate earthquakes, and 4) Source Modeling of large intraplate earthquakes. |