Opened for ship traffic on August 14, 1914, the Panama Canal is one of the great wonders of the modern Era and allows for ship traffic between the Pacific and Atlantic shipping lanes without having to make the arduous trip around the southern end of South America. However, the size of trans-ocean ships has increased tremendously, and many do not fit through the existing locks. Consequently, the Autoridad del Canal de Panamá (Panama Canal Authority, or ACP) has begun the process of modernizing and expanding the Canal to accommodate the increased transit demands and larger sizes of the newest post-Panamamax ships. As part of that process, we have been studying the faults of Panamá for almost four years, under contract to the ACP. Prior to our work, no active faults were recognized in Central Panama, although excavations for the canal in the past have exposed numerous faults and plenty of other evidence of crustal deformation. The results of our new work have caused a total paradigm shift in the perception of seismic hazard for one of the most important commercial structures in the world.

Our studies began with an effort to map tectonic geomorphic features along the faults that can be obviously seen from DEMs and airborne imagery. This was immediately followed by a field recon phase for the several hundred square kilometers centered on the Panama Canal, much of it covered in dense rain forest. Based on their geomorphic expression alone, it was clear that many of these faults had Holocene activity, and probably with non-trivial rates.

Following the geomorphic assessment, we completed paleoseismic investigations for the Gatún, Limón, and Pedro Miguel faults, including 3-dimensional trenching to resolve slip in the most recent events. Based on these trenching studies, we have developed slip rates, recurrence intervals, slip per event, and the timing and displacement for the last two-three events for all three faults. We also have trenched the Miraflores and Agua Dulce faults to determine their surface rupture threat to the Canal. All of these results are incorporated into the seismic design calculations for the new Canal Expansion structures, and for the retrofit of the existing structures. Our presentation will cover the gamut of studies that we have conducted for the Canal Expansion, will touch on the challenges of working in a place that receives three meters of rainfall per year, as well as provide an overview of the expansion project itself.

Eldon Gath - President of Earth Consultants International - BS University of Minnesota, PhD candidate at UC Irvine, with almost 30 years of experience in engineering geology in southern California and increasingly, over the last 10 years, international experience. He was President of the Association of Engineering Geologists in 1997-98, was active in the Southern California Earthquake Center for many years, and has served on numerous professional practice committees at local, state, and national levels. For the past several years, he has been trying to complete a PhD dissertation on the neotectonic evolution of The OC, while still commuting to Panama every couple of months. For the Panama work, he was the project manager for all nine of ECI's contracts with the Autoridad del Canal de Panamá. He is identified as the lead geologist on CH2M Hill's team for the Program Management of the Panama Canal Expansion Project.

Tom Rockwell, PhD, is a Senior Partner of Earth Consultants International and has been a Professor at San Diego State University for the past 25 years. He served as the head geologist for the Southern California Earthquake Center for 8 years, has served on numerous State and Federal funding panels, and has published over 400 papers, journals articles, book chapters, and guidebooks over the past 28 years. Rockwell is an expert on the tectonics and earthquake hazards of southern California and Baja California, has conducted extensive trenching programs to date earthquakes on faults in the western U.S., Middle East and Asia, and routinely uses soil stratigraphy and geomorphology combined with various radiometric dating techniques to assess rates of fault activity, determine recency of faulting, and date past earthquakes. His research focuses on understanding earthquake occurrence in time and space. Current projects include the characterization of fault systems behavior by understanding patterns of past recurrence of large earthquakes on faults in southern California, northern Mexico, Argentina, Portugal, Mongolia, India, Turkey, Israel, and of course, Panama. This work includes resolving information on slip per event, as it relates to understanding the controls on segmentation and rupture termination. He has also worked extensively on the affects of tectonism on the landscape, and the use of geomorphology to constrain rates and timing of tectonic events. Included in this latter aspect is detailed mapping and dating of marine terraces along the west coast of North America and assessment of paleosea level during the late Quaternary. In Panama he was the technical lead for all of the trenching studies and participated in all of the seismic hazard workshops.

Tania Gonzalez, Senior Partner of Earth Consultants International and a past Section Chair of the AEG's Southern California Section, received her BS and MS degrees in Engineering Geology, with a Minor in Archaeology, from Texas A&M University. She has almost 20 years of experience in geologic investigations, especially fault studies, here in southern California, in addition to Mexico, Turkey, and Central America. She has experience in absolute and relative dating techniques, including radiometric, thermoluminescence, and paleomagnetic sampling and interpretation, in addition to the use of soil development as a dating tool. Ms. Gonzalez has also managed and prepared dozens of municipal planning studies with emphasis on seismic and geological hazard mitigation. In Panama, she was the field manager for most of the geologic/geomorphic mapping and paleoseismic trenching studies.