On Saturday, April 16, 2016 a massive magnitude-7.8 earthquake rocked Muisne, Ecuador, with a maximum Mercalli intensity of VIII (Severe). GMS’s Ramon Gilsanz and Virginia Diaz traveled to Ecuador to help in relief efforts, assist other rescuers and collect data on the performance of structures during the event. The reconnaissance trip was coordinated by Geotechnical Extreme Events Reconnaissance Association (GEER), sponsored by the National Science Foundation, with additional support from the Applied Technology Council (ATC).
The earthquake was presaged by a magnitude 4.8 foreshock eleven minutes before the main quake struck, and followed by over fifty-five aftershocks in the first twenty-four hours. On April 20, a 6.1–6.2 magnitude aftershock struck 15 miles west of Muisne. (See the US Geologic Survey’s website for realtime updates about magnitude 2.5 or more anywhere in the world: http://earthquake.usgs.gov/earthquakes/map/)
Widespread damage was caused across Manabi province, with structures hundreds of miles from the epicenter collapsing. To date, at least 659 people were killed and over 27,700 injured. Unlike the strike-slip earthquakes in Japan, this one was a so-called megathrust quake, which occurs when one tectonic plate jams under another. In this case, the Nazca Plate is subducting beneath the South American continent at a rate of about 2.2 to 2.4 inches (55 to 61 millimeters) per year. Subduction along the Ecuador Trench and the Peru-Chile Trench farther south, has led to uplift of the Andes mountains and has produced some of the largest earthquakes in the world, including the 1960 M9.5 earthquake in southern Chile, the largest ever recorded event.
The US-Ecuador GEER team is led by Dr. Sissy Nikolaou of WSP | Parsons Brinckerhoff and Dr. Xavier Vera-Grunauer of the Universidad Católica de Santiago de Guayaquil and of the Geoestudios consulting firm. The NSF-funded US GEER team members include Prof. Kyle Rollins (Bingham Young University), Prof. Adda Athanasopoulos-Zekkos (University of Michigan), Prof. Clint Wood (University of Arkansas), Mr. Daniel Alzamora (Federal Highway Administration), and Ms. Gabriela Martinez Lyvers (US Army Corp of Engineers). The team also includes structural engineers Mr. Ramon Gilsanz and Ms. Virginia Diaz of Gilsanz Murray Steficek LLP, who are funded by ATC. The GEER Team is also working with self-funded engineers who have traveled to Ecuador, including Prof. Eduardo Miranda (Stanford University), Mr. Enrique Abel Morales (University at Buffalo), and Mr. Roberto Luque (UC Berkeley).
The Ecuador GEER team includes geotechnical and structural engineers from regional universities, agencies, and private firms: Dr. Fabricio Yepez (San Francisco of Quito University), Mr. Juan Vera-Grunauer (structural engineer), Mr. Adolfo Caicedo (geotechnical engineer researcher, Catholic University of Guayaquil), Mr. Guillermo Ponce (structural engineer), Dr. Walter Mera (structural engineer and vice president of Catholic Univ. of Guayaquil), Prof. Francisco Ripalda and Claudio Luque (geotechnical engineer, Catholic University of Guayaquil), Mr. Gonzalo Vela (structural engineer, logistic leader of Corps of Engineers-COE technical team, PNUD, United Nations), Ms. Carolina Salcedo (regional coordinator of COE technical team, Ministry of Housing), and Dr. Alexandra Alvarado (National Geophysics Institute).
The GEER team is focusing on documenting the geo-effects of the event, with special emphasis on soil-structure interaction and lifeline performance, as well as ground motions, liquefaction effects, and landslides. US GEER members are interacting with top Ecuadorian government officials through their collaboration with the top Ecuadorian earthquake professionals.
The US-Ecuador GEER team will share their findings in a report posted at the GEER website: http://www.geerassociation.org/.