THE CALIFORNIA "RECENT LANDSLIDES" DATABASE: A TOOL FOR IMPROVED UNDERSTANDING OF LANDSLIDES AND LANDSLIDE TRIGGERING MECHANISMS IN CALIFORNIA (Invited Presentation)

The nascent California “Recent Landslides” database compiled by the California Geological Survey (CGS) is an innovative data repository for the collection and communication of statewide landslide data. The data repository is presented to the public as an online interactive ArcGIS Online map displaying landslide locations and data to show varying scales of landslide processes affecting Californian citizens, businesses, and infrastructure. Currently the landslide database comprises thirty-eight (38) landslide events that occurred as early as July 21, 2018 until as recently as March 26, 2019. Landslide events are classified by forty-nine (49) data fields and include (if available) a representative photograph to increase the educational impact of the landslide processes attributed to each event. Of the data fields, seven (7) are public facing: Landslide Date, Nearest Place, Info Source, Impacts, Damage Description, Latitude, and Longitude. The remaining forty-two (42) data fields are for internal scholarship and analytic purposes, designed to promote a deeper understanding of the landslide processes responsible for each event. When available, rainfall intensity data recorded in the vicinity of landslide events is collected and categorized as antecedent and/or in-storm. Triggering observations are recorded per event. Interpretation confidence is based on a combination of remote sensing and field reports, and classified as “probable” (75% confident), “definite” (100% confident), or “questionable” (50% confident). Reported landslides are field checked by CGS personnel if possible to verify their interpretation confidence. When possible, a landslide “Quick Report” may be generated for noteworthy landslide events. With the continued development of this database, the CGS endeavors to reach Californians and California governmental agencies with data useful for education and planning purposes. The development of the "Recent Landslides" database is considered vital to better describing the causes of storm-induced landslides. It is the aim of the CGS to eventually implement the database as a tool to provide statistical insights into frequency of given landslide types.