The active faults for the fundamental survey were selected according to the following standards, with the purpose of efficiently conducting an active fault survey in "Plans for Fundamental Seismic Survey and Observation" by the Headquarters for Earthquake Research Promotion.

(Standards)

In "Active Faults in Japan, Revised Edition" (1991, University of Tokyo Press), selection is to be made from among certainty I or II, and activity A or B, and those that meet the following standards, in principle.

1) The length of the fault is 20 km or more.

2) When the length of the fault is less than 10 km, and multiple active faults with almost the same strikes are distributed close by within a distance of 5 km or less, and the full length is 20 km or over, thus forming an active fault zone (group).

When existing survey materials are inadequate, and it is necessary to reevaluate the data themselves, due to such factors as geological conditions, or when the active fault is distributed on a land area, including extensions into the ocean area, the full length of the fault has a high possibility of being 20 km or longer. These factors were considered for the selection.