Phys.org December 12, 2024
An international team of researchers (USA – UC River Side, Japan, New Zealand) observed and further exhumed curved slickenlines on fault planes associated with paleo-surface rupture of the Alpine Fault in New Zealand’s continental transform plate boundary. Rupture modeling indicated that the geometry of such curvature provided a record of past earthquake rupture directions. They studied three sites that spanned a region known to variably halt or allow passage of past earthquakes to contribute rupture direction constraints to the fault’s paleoseismic record. In two sites they observed both convex-up and convex-down curved slickenlines on and adjacent to principal slip surfaces which indicated past ruptures from both the northeast and southwest of these locations. According to the researchers their results demonstrated the utility of curved slickenlines as a valuable new paleoseismological tool for determining past rupture directions, applicable to surface-rupturing faults globally… read more. Open Access TECHNICAL ARTICLE
(A) Simplified active tectonic map of the South Island of New Zealand with Alpine Fault in red… Credit: Geology (2024) 52 (12): 917–921.