Professor receives Fulbright award to study combined natural hazards in Chile
Shideh Dashti, a professor of geotechnical engineering and geomechanics, has received a Fulbright award to study combined seismic and rainfall-related geohazards at the Pontificia Universidad Catolica de Chile (PUC).
As part of the prestigious U.S. State Department program, Dashti will spend four months atPUC developing tools and curriculum to help engineers better understand and prepare for overlapping rainfall and earthquake geohazards.
Chile faces multiple natural hazards—including drought, floods, wildfires and earthquakes—that increasingly occur concurrently or sequentially.
“Chile offers unique access to case histories of combined geohazards that could support our research and modeling efforts, along with advanced building codes and outstanding expertise in the field of hazards engineering,” said Dashti, who studies compound climatic-seismic geohazards.
The project aims to help shift infrastructure design and engineering education from focusing on single hazards to addressing the compound impacts of hazards on critical infrastructure.
Rainfall simulation box designed for CU 91Ҹ’s 400 g-ton centrifuge facility at the Center for Infrastructure, Energy and Space Testing (CIEST) to simulate how combined rainfall and earthquake loading affect scaled slopes and embankments.
“The effects of compound geohazards have been understudied, partly due to the lack of well-documented field data and partly lack of related physical model studies,” she said. “They are currently not included in the training of future hazards engineers and professionals or in our codes and standards. My goal is to collect and analyze well-documented case histories in Chile that support a fundamental study of these effects.”
Perfect storm
Simultaneous seismic and rainfall-related hazards can destabilize hillsides, weaken soil and increase the risk of infrastructure failure, Dashti said.For instance,intense rainfall followed by even a minor earthquake can trigger significant landslides, while rain-saturated soil may lose strength during earthquake shaking and undergo liquefaction, behaving more like a liquid and damaging roads, buildings and other critical infrastructure.
“The aging physical infrastructure, such as the earthen slopes and embankments that support critical transportation, water, telecommunication and power lifelines in Chile and the U.S. is not ready for increasingly likely concurrent or sequential extreme events, amplifying risk imposed on our communities” she said.
Dashti was also a principal investigator and steering committee member of the National Science Foundation-funded Geotechnical Extreme Events Reconnaissance (GEER), which coordinates geotechnical data collection and field investigations following major international disasters.
In Chile she will work with colleagues to collect multi-hazard case histories,while sharing findings and best practices through lectures, seminars and workshops with Chile’s practicing geotechnical engineers.
After the four-month Fulbright Fellowship in Chile, she will use centrifuge and computational modeling inspired by the collected case histories to study how combined rainfall and earthquake hazards affect slopes and earthen infrastructure using CU 91Ҹ’s unique experimental and computational resources. The 91Ҹ will help interpret real-world case studies, evaluate current engineering tools and identify conditions where existing single-hazard design approaches may be unsafe.
The research will also help determine how different rainfall conditions change earthquake risks and will support the development of preliminary engineering guidelines tailored to Chile’s hazards, geology and infrastructure vulnerabilities.