2:15 PM - 2:30 PM
[S02-5-04] Seismic hazard assessment for induced seismicity in the Middle Urals, Russia
Traditionally common methods of seismic hazard assessment for wide territories including countries or large regions take into account only natural tectonic earthquakes. Such approach is obviously correct if the natural seismicity is dominant. But in some regions the contribution of induced earthquakes as well as nontectonic seismic events may be comparable to tectonic one or even prevail over it.
We have tried to estimate the contribution of induced earthquakes occurring in the Middle Urals that is the region of moderate seismic activity, where hundreds of deposits of different mineral types are under exploration. To obtain reliable result we followed the idea of probabilistic-deterministic forecasting of dangerous seismic processes according to common methodology offered by V.I. Ulomov. To estimate an actual seismic hazard for some mining districts, we used the data set of hundreds of natural and induced earthquakes and macroseismic data for the strongest ones. It was elaborated two prognostic models. The first one is the model of seismogenerating zones, describing parameters of whole variety of induced and man-made seismic sources that may occur in the region. The second one is the model of the seismic effect generated by induced earthquakes. Both models differ sufficiently from ones elaborated earlier only for natural seismicity by other researchers.
As result, a set of new maps in terms of seismic intensity and peak ground acceleration for the Middle Urals had been obtained. They show earthquakes only from three mine districts may generate the most significant seismic effect. In two districts there are conditions for generating shallow Mw 4.5 tectonic events, that caused by stress-strain changes due to deep mining. The third district may generate strong collapses. Hundreds of other zones are not able to induce events that produce effect greater than background normal level (5 points of MSK-64 scale).
We have tried to estimate the contribution of induced earthquakes occurring in the Middle Urals that is the region of moderate seismic activity, where hundreds of deposits of different mineral types are under exploration. To obtain reliable result we followed the idea of probabilistic-deterministic forecasting of dangerous seismic processes according to common methodology offered by V.I. Ulomov. To estimate an actual seismic hazard for some mining districts, we used the data set of hundreds of natural and induced earthquakes and macroseismic data for the strongest ones. It was elaborated two prognostic models. The first one is the model of seismogenerating zones, describing parameters of whole variety of induced and man-made seismic sources that may occur in the region. The second one is the model of the seismic effect generated by induced earthquakes. Both models differ sufficiently from ones elaborated earlier only for natural seismicity by other researchers.
As result, a set of new maps in terms of seismic intensity and peak ground acceleration for the Middle Urals had been obtained. They show earthquakes only from three mine districts may generate the most significant seismic effect. In two districts there are conditions for generating shallow Mw 4.5 tectonic events, that caused by stress-strain changes due to deep mining. The third district may generate strong collapses. Hundreds of other zones are not able to induce events that produce effect greater than background normal level (5 points of MSK-64 scale).