ESTUARINE RESPONSE TO DISTURBANCES: A HOLOCENE RECORD OF STORM EPISODES, TECTONICS, AND CLIMATIC SHIFTS AS PRESERVED IN COASTAL SYSTEMS IN SOUTHERN CALIFORNIA

Southern California is highly susceptible to hazards related to seismic activity and shifts between drought and large precipitation events such as those associated with El Nino ocean circulation patterns and atmospheric rivers. These hazards are capable of incurring flooding, landslides, and coastal erosion and threaten the state’s large coastal population centers. The scale of damage associated with past events (IE the winter storms of 1861-62 A.D.) is significant enough to warrant the USGS to create the ARKStorm Project to better model future occurrences of events of this magnitude. While valuable, these predictions are based on a relatively short period of scientific observation and historical record (<200 years). Efforts to improve the record of the frequency, timing, and duration of these large scale storm events include the study of lacustrine sediments as well as offshore basin sediments; however, little is known regarding the preservation potential and scale of these events recorded in coastal systems such as estuaries and lagoons. Here we present a detailed textural and geochemical analysis of a suite of sediment cores from several estuarine and lagoon systems from coastal Southern California. This collection of cores provides a detailed record of Holocene storm episodes as well as climatic shifts across coastal Southern California. Clustering of the deposits accompanied by high degrees of correlation throughout the study region may also better reveal phases of prolonged drought and increased precipitation in Southern California. Our results are significant in the context of both increasing urbanization of coastal areas and global warming, as some models suggest the magnitude and frequency of large-scale precipitation events accompanied by flooding and erosion could increase with general warming.