Earthquakes, floods, sea-level rise and sudden shifts in river courses threaten many of the 150 million Bangladeshis living in the low-lying Brahmaputra River delta. Scientists from Lamont-Doherty, Dhaka University and other institutions have begun a five-year project to understand the hazards and the possible hidden links among them. Lamont geophysicist Michael Steckler keeps us up to date on the work.
Geohazards in Bangladesh
Finishing the GPS Scouting
Columbia University researchers are part of a team that is exploring a plate boundary that crosses three countries: Bangladesh, India, and Myanmar. Click here to read the previous blog posts in this series.
After the drive yesterday, it was clear the car needed fixing. No need to rush out early in the morning and I got some much needed sleep for my jetlag and my cold. After a later (for us) breakfast, Bulbul, our driver took the car to be fixed. We took an autorickshaw to the first site to add the chain and lock security system and see the sky view without the trees. This time we had neither a ladder nor a truck to climb on. Keith and Sanju scaled the building, but I was still shaky from the cold and stayed
below. I worked on my blog until I ended up showing a group of kids my photos. That was where I was when they found me after completing the short job. My choice to stay down was reinforced by learning that Sanju had fallen on the way down. A piece of the concrete roof had broken off in his hand and he fell backwards onto the cut down tree. Luckily he was OK. His glasses frame was broken, his elbow banged up and had a some scratches from thorns, only minor injuries. With the car still being repaired,
we had some enforced free time. We went to a famous shop outside of Srimongal, past a rubber tree plantation, where they serve 7-layer tea. In fact, this was where it was created. Carefully pouring (I presume), they float 7 distinct layers of different colored teas on each other. Refreshed, we headed back to wait for the car, and Keith repaired Sanju’s glasses.
It was too late for an installation that was
an hour drive away, so we turned our attention westward. We were reoccupying a site at a college (high school) in Chunarughat, but we also had one more place to scout. This one was to be co-located with a seismic site, B4. The advance team found a home, but it would require constructing a monument. We went to see for ourselves if it would work for us, passing one of the two seismic teams joining us in Srimongal – Nano, Céline, Alissa and Karim. A few minutes of greetings and
we were both back on our way. Driving across the rice fields, with a few wrong turns, we found the direct road had a bamboo bridge we could not cross. We had to double back and take a longer, more roundabout route ending with bumpy dirt roads that were not meant for cars. Finally, we hit another bamboo bridge less than a kilometer from the site. We walked there and met the owner of the house. It would be usable
for seismometers, but there was no open sky view for us. We walked another kilometer farther, but this time we had no luck. The school was surrounded by trees. We were told that there was another school at a place called Kalenga with no trees. By now it was dark, so we headed to the dinner with the seismic team. They were having a more difficult time. Permissions were not finalized and appeared to be harder to get.
The next day we went to Chunarughat to do the reinstallation. I have been here a few times since the initial visit in 2007. The last time I saw the antenna, it was loose and assumed it was a problem with the mount. Instead, it was more serious. The rod itself was loose and had rotated. Two silver threads on the rod were visible
beneath the green weathered ones. Looking at my photos we pieced together that the antenna cable came loose and the straightening of the loops to relieve tension had rotated the antenna 1.5 times so the north end was pointing south. The unscrewing created a 3.5 mm increase in the height of the rod. I will have to look at the data carefully to see if we can figure out when it happened and correct it. Keith then carefully unscrewed it, added a really strong epoxy and screwed it back to its original level. Sanju and I took rickshaws into
town to buy more electrical wire for the solar panel and for grounding. After a while, Chunarughat was up and running again.
After some tea and snacks, it was time for the last task – finding the final GPS site. We went off in search of the now mythical Kalenga. I didn’t understand why everyone we asked seemed to know the direction to Kalenga until I realized there was a Forest Reserve of the same
name. We continued along progressively worse roads until the colorful school at Kalenga appeared. It was indeed open, surrounded on two sides by rice fields. Although it was on the anticlines, the rivers eroding it had created valleys suitable for rice. The school principal quickly agreed to the installation. We didn’t have more equipment with us, but we had the drill. That would save us some time tomorrow, so we drilled until the power ran out of the batteries. None of these schools had power, so instead of the large drill, we had to use the smaller battery-powered
one. We had been needing to recharge the batteries to do all the drilling, but with this early start, perhaps we would not. In any case, sites for all the GPS had been located and arranged. All that was left was the mechanics of the actual installation for the last two sites.