Notes on the Yanagase Fault, Japan

Abstract

The Yanagase fault can be traced 55 kilometers as the northeastern limit of the Biwa Lake basin.1) There are fault-line valleys that follow the line of the fault. It has been inferred that the fault is of recent origin on the basis of geomorphological and geological features.2) The earthquake of Anegawa in 1909 has been suggested to be related to the fault. Releveling of bench marks across the southern extension of the fault indicated uplift on the northeast side of it (fig. 3; after A. Imamura, 1928).3) The fault may be a left lateral strike slip one on the basis of some evidences (figs. 4 and 6) including offsets of dykes (fig. 5).4) In this region some younger faults with trends nearly parallel to the Yanagase fault show evidence of left-hand displacement (fig. 1).5) The stress distribution inducing the earthquake faults is believed to be rather consistent and indigenous to the region, at least during the Quaternary period.