Discussions with the Ecuadorian military, who were in charge of the emergency response following the earthquake.)
Fiona Hughes is a Student Member of EEFIT (Earthquake Engineering Field Investigation Team). In 2016 she participated in an EEFIT mission to Ecuador. Here she describes her part in the mission and the significance of a new report.
I was part of the 2016 Earthquake Engineering Field Investigation Team (EEFIT) that visited Ecuador following the Mw 7.8 Muisne Earthquake. The earthquake caused an estimated 668 fatalities, 6,300 severe injuries and widespread damage in the northern Ecuadorian province of Manabi. The EEFIT team visited the area for around two weeks.
Our objectives were to carry out a general assessment of damage to the building stock and other structures; to document and observe soil failures, landslides, liquefaction and faulting; to obtain measurements and acquire data whenever possible; to develop a view on the response to the event, and to investigate the socioeconomic effects of the disaster by interviewing people from the region.
The team that was deployed in Ecuador consisted of Harriette Stone, Bayes Ahmed (both University College London), Nina Jirouskova (Imperial College) and myself (University of Cambridge), all working on our PhD theses in the UK, plus Sebastian Kaminski and Jorge Lopez, earthquake engineers at Arup, and Guillermo Franco from reinsurance broker Guy Carpenter.
Above: Inspecting reinforcement bars from collapsed buildings
Above: Looking at column detailing
Together we covered several disciplines including structural and geotechnical engineering, social sciences, and risk management. Our report contains many analyses of the vast amount of data collected, a large number of photographs of the damage observed, and discussions on the patterns we observed.
Key findings include:
• Very high levels of structural damage were seen in non-engineered, low-rise reinforced concrete buildings with masonry infills. Through several walking surveys, we collected valuable information that may be used to produce vulnerability functions to improve our earthquake risk models.
• Following discussions in the refuge shelters, it was found that most of the families that had been affected had lived in multi-storey buildings made of reinforced concrete or reinforced concrete combined with timber and bamboo. Following the earthquake most wanted to relocate into single-storey buildings that were made of lighter materials such as timber and bamboo.
• We saw many instances in which geotechnical failures were aggravated by elevated river levels and a high water table at the time of the main shock, due to previous flooding.
• Liquefaction induced damage was widespread, particularly lateral spreading along river banks.
Above: drone image of landslide at a cattle ranch near San Isidro, which destroyed three buildings and killed 80 cattle.
Collaborating with the British Geological Survey (BGS), we were able to pinpoint many of these failures using innovative satellite imagery. We conducted a ground-truthing exercise to validate that this type of remote sensing information helps to quickly obtain an estimate of landslides in the affected areas. We also saw some instances in which these forecasts failed, which will be useful to identify the limitations of these methods.
The EEFIT mission was during the first year of my PhD and it provided me with an invaluable opportunity to observe earthquake damage, learn more about disciplines related to earthquake engineering, and to begin to appreciate the difficulties of disaster response and emergency relief. In addition, I was able to use several case histories for my PhD research.
It was also great to meet and work alongside other professionals and to expand my involvement within the seismic community working in the UK and beyond. I am grateful to my PhD supervisor for encouraging me to apply to be part of this mission and to EEFIT for giving me this great opportunity. I strongly recommend others to do the same.
Read EEFIT's Ecuador report and browse past mission reports