APPLICABILITY OF SLIP TENDENCY FOR UNDERSTANDING LONG-TERM FAULT ACTIVITY: A CASE STUDY OF ACTIVE FAULTS IN NORTHEASTERN JAPAN

Abstract

The assessment of fault activity is necessary to mitigate against damaging earthquakes. To adequately assess long-term fault activity, a new technique that complements chronological investigations is required. Here we examine the applicability of the slip tendency (ST) method, based on physical models, to assess fault activity in Japan. We computed the ST using a friction coefficient of 0.6 for the faults, a common friction coefficient for rocks, and the stress state estimated from earthquake focal mechanisms in northeastern Japan. Calculated ST values are high for the most active faults (e.g., the Senya segment) and are low for inactive fault (e.g., the Sakunami-Yashikidaira segment). Therefore, we propose that the ST method can be applied in assessments of fault activity. However, the ST method sometimes underestimates fault activity, and we have explored the necessary input parameters to obtain reliable results. To use the ST method, the determination of these parameters is critical for the robust assessment of fault activity based on physical models.