Baja Reconnaissance – Heading to the Epicenter
After spending a good part of the day in El Centro and Calexico our Degenkolb reconnaissance team split in two. Lisa Everingham and Jeremy Callister stayed in Calexico to observe the damage in the downtown area. Chris Poland, Ricardo Hernandez, Silvia Mazzoni, Travis Sanders and I (Daniel Zepeda) headed down to Mexicali to observe the damage near the epicenter.
Most of what we had seen and read on news reports indicated that Mexicali had been hit the hardest. News reports such as yesterday’s article by LA Times had reported that a parking lot had collapsed, a Hospital evacuated and 5,200 homes damaged. A fireman in Calexico informed us that his department had spent a good part of the week in Mexicali distributing food and water. Our team eagerly drove to Mexicali to witness the reported damage. Given our limited time, we decided to head straight on Mexico’s Highway 5 towards the epicenter (32miles from Calexico) and work our way back.
Once we crossed the border, we noticed people were going about their business as if nothing had happened. While driving through downtown Mexicali, we only observed minor damage on a few structures. Some of us started to wonder if the media had exaggerated the earthquake damage. However, as we proceeded on HWY 5 towards the epicenter we began to encounter cracks in the road that had been filled with gravel. The side of the road began to show sand and water and in many areas we saw what appeared to be sand boils. It was quite interesting given that most of us had never seen this.
About 20 miles from the US border we noticed a church on the side of the road that had a partial collapse. It was made of concrete frames with masonry infill. The church had a small concrete tower in the front that had collapsed and damaged other areas of the roof and walls on it’s way down. There were also some partial out of plane masonry infill failures towards the back of the building and severe damage to the ceiling. As we got out of the car a local woman greeted us. She informed us that she was in charge of the church when the priest was away. She proceeded to give us more information on the building. The church was named Nuestra Senora de la Merced and had been incrementally constructed over the past 50 years. The loss of the church was a big loss to the community. It was a depressing moment as she told us that they had been told by others that they may have to demolish the church. In our opinion the church had performed fairly well. It did have partial collapse but the main structure remained stable. Our new friend was glad to hear our opinion given that importance of the church to the community.
After spending some time at the church we got back on the road and proceeded towards the epicenter. The lady at the church encouraged us to stop by 4 neighboring communities, who had suffered lots of damage, Sacamoto, Nayarit, Cucapa, and La Puerta. In simple terms she described how homes were destroyed by soil liquefaction and lateral spreading. Unfortunately, our limited time did not permit us to stop in these areas. However, after leaving the church we did come across a couple of areas where people who had lost their homes were living in tents. A gas station attendant informed us that there were rumors that the government will not let these people re-built in the same areas due to fear of future soil damages. It was not clear where these poor people would be relocated to. I wondered to myself if the government would do an engineering evaluation prior to taking these measures.
After driving for some time we finally reached the epicenter, or close to it. It was not clear whether we got there or not but the location was close to the one published by USGS. After minutes of rest and taking some photos we headed back to the US. Ricardo Hernandez returned the next day with the EERI team and informed us that he saw some structural damage to major structures in the Mexicali downtown area which were caused by soil liquefaction and lateral spreading.
Thinking back to our experience in Mexicali, El Centro and Calexico I wonder how resilient these cities were after the earthquake. All 3 cities had some structural damage to their downtown areas. However, with exception of some school buildings in Mexicali (see Ricardo’s blog), much of the structural damages happened in retail areas rather than essential facilities. A couple of Hospitals were evacuated in Mexicali after the earthquake; however, Ricardo visited the Hospitals and informed us that the evacuation was mostly out of precaution rather than severe structural damage. According to the LA Times, Mexicali did have 5,200 homes damaged but this is in a city with over 1 million residents. The media has reported that only two people have died in what is the largest earthquake the region has seen this century. In my opinion it seems that all 3 cities were very resilient, and I hope that this earthquake like many in the past shows us that building code enforcement not only saves lives but helps cities get back on their feet after a major seismic event.
