ENERGY PARTITIONING FOR SEISMIC EVENTS IN FENNOSCANDIA AND NW RUSSIA
We address the problem of energy partitioning at distances ranging from very local to regional for various kinds of seismic sources, and are now in the last year of this three-year effort. On the small scale we have focused on analysis of observations from an in-mine network of 16-18 sensors in the...
| Main Authors: | , , , , , , , , , |
|---|---|
| Other Authors: | |
| Format: | Text |
| Language: | English |
| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.500.4653 http://www.ldeo.columbia.edu/res/pi/Monitoring/Doc/Srr_2005/PAPERS/03-05.pdf |
| Summary: | We address the problem of energy partitioning at distances ranging from very local to regional for various kinds of seismic sources, and are now in the last year of this three-year effort. On the small scale we have focused on analysis of observations from an in-mine network of 16-18 sensors in the Pyhäsalmi mine in central Finland. This analysis has been supplemented with 3-D finite difference wave propagation simulations to investigate the physical mechanisms that partition seismic energy in the near source region in and around the underground mine. On the local and regional scale (20-220 km) we have targeted events from the region offshore Western Norway where we have both natural earthquake activity as well as frequent occurrence of underwater explosions carried out by the Norwegian Navy. Since the previous reporting of this project at the 2004 Seismic Research Review (Bungum et al., 2004), we have extended the finite difference simulations in the 3-D geological model of the Pyhäsalmi mine. This model, which encompasses a geologic volume 500 meters in each direction, includes 3-D representations of the ore bodies, exca-vated regions, tunnels, and voids. The model is discretized on both 2 and 4 meter grids making it possible to simulate seismic energy up to 100-200 Hz. We perform a variety of sensitivity tests to determine the mechanisms that produce shear energy in an underground mine environment. For example, we conduct a suite of 15,000 (2-D) explosive source simulations to quantify the influence of source location on the amplitude of generated shear energy. In fact, most of |
|---|