LANDSLIDE DATA COLLECTION AND MAPPING FROM 2017 TO PRESENT USING THE CALIFORNIA GEOLOGICAL SURVEY’S REPORTED CALIFORNIA LANDSLIDES DATABASE AND WEB MAP

Landslides are a widespread geologic hazard across California variously impacting public, private, and commercial infrastructure, as well as human life. To better understand the distribution and impacts of landslides throughout the state, the California Geological Survey (CGS) created the Reported Landslides Database (RLD) and web map in 2018. The purpose of the RLD is to catalog and map reported landslides, document triggering meteorological data where available, maintain situational awareness for emergency response, and provide accurate landslide hazard information to the public. RLD data is collected by CGS geologists assimilating available reported landslide data from multiple sources including, but not limited to: photos and event timing information from crowd-sourced reporting (e.g. X, Facebook), local news media sources, state, county, and municipal agency reporting, California Highway Patrol (CHP) data, National Weather Service (NWS) data, and review of firsthand reports provided by the public. Key data included for the RLD includes photos and video footage, latitude and longitude, rainfall totals, landslide type classification, reported infrastructure damage descriptions, landslide triggering information, and reported timing information. Publicly available RLD data is mapped using an ArcGIS online web map. The RLD now has 2,331 documented landslides and is valuable as a tool for situational awareness: during severe winter storms in the 2022-2023 and 2023-2024 water years, respectively, the RLD was instrumental in providing state and federal officials with critical information regarding the most highly impacted areas of the state. CGS staff collectively utilized RLD and web map data and worked to provide situational awareness of statewide landslide hazards to the State Geologist through partnership with various government and community sources. These data directly contributed to information relayed to the Governor’s Office of Emergency Services and federal officials by the California State Geologist that resulted in multiple state of emergency declarations from the Governor of California and the President of the United States, as well as 13 landslide assessment CGS mission tasks to highly impacted areas in 2023.