Abstract
Information on spatial and temporal distribution of stress state and fault strength within seismogenic zones is essential for improving the accuracy of long-term forecasts of large earthquakes. We would be able to specify the area with a high probability of earthquake occurrence, if we know distribution of highly stressed areas in comparison with their strengths. Although at present we don't have a method to measure stress and strength within the seismogenic zone and it is extremely difficult to establish the method, we need to make every effort to extract information on stress and strength and that on their fluctuations in time and space through observations and surveys.
