Lacustrine evidence reveals spatially and temporally distinct holocene ruptures on the Sawtooth Fault, Central Idaho, USA

The Sawtooth Fault in central Idaho, USA, is a range-bounding normal fault with Late Pleistocene–Holocene scarp near the up-valley ends of several range-front lakes. Cores from Redfish Lake, which spans fault, exhibit evidence catastrophic sediment re-mobilization two sequences consisting variably intraclastic mud-clast conglomerate, massive homogenite, and graded silt clay. Event strata younger sequence are unconformable contact Pleistocene sediments cores on northern lake-basin slope, suggesting transport down-valley portion lake toward basin center. A cap associated event preserved at all coring sites. sequence, distributed lake-wide, dates to ca. 4300 cal bp, while additional Lake pre-date 7627 bp Mazama ash. We propose seismic triggering disruptions. Asynchronous stratigraphy Pettit 15 km south suggests distinct ruptures along portions Fault. sedimentology geochemistry remobilized both lakes indicates that sources included early Holocene lake-floor failures cut deeply into sedimentary sequence. collected Stanley (17 northwest Lake) following nearby 2020 M6.5 earthquake thin, sandy horizon documented delta collapse. Subaerial slope left no widespread disturbance Lake. conclude large-magnitude remobilization events probably required rupture sections proximal