Paleoseismology Along the Newport-Inglewood Fault Zone

SAFRR M.S. student Robert Leeper is continuing work that may lead to a better understanding of late Holocene seismicity along the Newport-Inglewood fault zone. Multiple sediment cores taken from the Seal Beach wetlands have shown organic-rich sediment at greater than 2 meters depth. Robert's hypothesis is that the organic-rich sediment represents the relic marsh surface that abruptly subsided during a major earthquake approximately 1800 years ago. Next steps include identification of exotic pollen and determination of the depth at which Cs-137 spikes, which will help establish an age model for the marsh sediment. Microfossil analyses near 200-cm depth will also help determine if an abrupt change in the depositional environment occurred in the past