NSF Award
2410685
The Eastern North Pacific basin is one of the most active areas globally for hurricane development. Western Mexico, in particular, is often impacted by powerful hurricanes, capable of causing catastrophic storm surge and/or torrential rainfall, as demonstrated by the devastating impacts of Otis in 2023. Unfortunately, observational hurricane records for Western Mexico only go back about 75 years, making it challenging to understand how often hurricanes strike this area, and the climate mechanisms that drive such activity. Both challenges make proper risk assessment difficult. During this project, sediment cores will be collected to help reconstruct past environmental conditions and evidence of past hurricanes going back hundreds to thousands of years. Field research will take place in Jalisco and Nayarit. These two states represent a vast spatial gap with limited research data about previous environmental conditions and hurricanes. Improved assessment of regional coastal risk will help policymakers, stakeholders, and residents make sounder, more scientifically based decisions. This project includes a new collaborative network with universities in Guadalajara, Jalisco (ITESO) and Quintana Roo (ECOSUR). As part of this collaboration, PI Bianchette will deliver seminars for interested students on natural hazards and related topics at ITESO, and will also host a field school where students will gain experience with sediment coring and field techniques.<br/><br/>Reconstructing hurricanes along Mexico’s Pacific coast is complicated by the vast dimensions of beach ridge plains, frequency of tsunamis, and difficulty locating depositions from historic (modern) hurricane events. Currently, there is no scientific consensus regarding the proper identification of extreme event deposits (i.e., hurricanes, tsunamis) along Mexico’s Pacific coast, since studies often lack significant spatial coverage and comparisons to modern analog deposits. Thus, there is a notable lack of understanding of geological processes along typical coastal environments of Western Mexico. Coupled with past research experience from Mexico’s Pacific coastal environments which includes sampling multiple sites and extracting ~100 meters of sediment, an analysis of aerial images from hundreds of kilometers of coastline has helped PI Bianchette to identify at least 10 sites likely to contain modern hurricane deposits. Identifying and characterizing these modern signatures is essential for detecting paleohurricane deposition and accurately differentiating it from tsunami-induced runup layers. Multi-proxy analysis (e.g., geological, biological, chemical methods) of these recent deposits will help determine the marine and terrestrial impacts of both modern events and paleohurricanes, further improving regional risk assessment and mitigation. Results will be aligned to paleoclimatological datasets to understand the mechanism(s) (i.e., ENSO, ITCZ) responsible for hyperactivity, leading to sensible prognostications of future activity to aid climatologists and modelers. Notably, these methods, both field and laboratory, can be applied to other similar coastal regions throughout the world, where extreme event deposition has been challenging to pinpoint and identify its provenance.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
