DIGITAL DATA COLLECTION TECHNIQUES IN NATURAL HAZARD EVENT RESPONSE: EXAMPLES FROM THE CALIFORNIA GEOLOGICAL SURVEY’S EVENT RESPONSE EFFORTS (Invited Presentation)

The California Geological Survey (CGS) responds to natural hazard events to document hazards and risk to life-safety and property, and provides emergency response managers this information, enabling them to make informed public safety and land-use decisions.

CGS uses the ArcCollector application on mobile devices for event response. This cloud-based platform enables collection of consistent data attributes, real-time editing, use of multi-layered datasets, and timely evaluation and distribution to emergency management agencies. Attribution fields within ArcCollector are customized for various response efforts, such as post-wildfire assessment, debris flow inundation, flooding and tsunami inundation, and earthquake ground failure mapping.

During the Ridgecrest Earthquake response in 2019, collaborative field teams used ArcCollector to record surface rupture displacement and ground failures using a combination of points and line streaming features, in a multi-layered dataset. Office-based optical image correlation identified potential surface ruptures were added as a layer in ArcCollector (Morelan and Hernandez, 2020). Helicopter overflight paths were recorded using line streaming, and observations of ground failures were collected with points, which allowed field teams to target impacted areas. The optical image interpretation layer guided field teams to verify evidence of the interpreted surface displacement, resulting in accurate location of measurable surface rupture.

Post-wildfire watershed evaluation teams mapped values at risk to debris flows in response to the 2017 Thomas Fire. Within days of the fire being extinguished, a large storm cell blanketed the area resulting in deadly debris flows from multiple canyons in the Montecito area. CGS and USGS field teams collected inundation observation data from this event in coordination with State (CAL FIRE) and local agency partners. Inundation boundary and flow depth information was collected and distributed to the local agencies, along with geologic information, that was directly used in redevelopment and hazard mitigation and evacuation planning.

In all response settings, the CGS use of ArcCollector allows field teams to rapidly collect important data and distribute findings to emergency management agencies.