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 seismologist Michael Steckler keeps us up to date on the work.
Humayun and I arrived in Sremongal and were reunited with the others. After dinner, the gravity meter that Céline will use for measurements here after we leave finally arrived, making Céline very happy. It had been stuck in customs getting clearance for days as she impatiently waited for it to arrive. As time was growing short, Céline suggested that we should split into two installation teams and each do one of the far northern sites. Alissa, Humayun, Sanju and I went to BN05 while Celine, Nano, Paul and Karim went to BN04. Both are
2-3 hours away, but potentially longer if the roads are bad. Traveling through extensive fields of rice, the road was surprisingly good for someplace so remote and easily flooded. As was often the case, the scouted site was not good, so we called the chairman. While he wasn’t home, his brother was and after a long conversation with Humayun, offered his family’s home. It was large enough that there were several options, but one was clearly better than the others and we installed one of our smaller waterproof seismometers, just in
case of flooding. We were now experienced and completed it in less than 2 hours. More tea and photos and we were on the long road back. Céline’s team was also successful; two sites in one day put us back on track.
We again split the next day, with Céline, Alissa, Humayun and myself going to install B9, while the others went to look at the geology in the hills farther east. along the way they also stopped off at a tea garden to scout BN01. B9, officially BA09, had already been scouted, so we
quickly installed and took pictures with the family. After that was done, we went to service some stations, collecting the few days of data to make sure everything was working well and analyze the noise levels at the sites. We stopped at B10, where the owner treated us to his boroi, small apple-like fruits. Then we went to B8 located at a manager’s house in a tea garden. We wanted to do B7 as well, but they had important guests visiting and did not want us to come by today.
The next day was our last installation in this region, the Sylhet Division of Bangladesh. We again split into teams for the final installation, for doing field geology, and for servicing. Karim and I did the service runs. We did B3, outside a private home, then B2 in a tea garden manager house. We only saw the 6 servants that maintained the property. As we left, Karim pointed out that he thought two of them were transgender. Next was the long hard drive to B1. As we came close we called the manager to
ask about sending his jeep to drive the last stretch of road. However he had guests, so we had to walk the last mile to the tea garden. Along the way, we passed crews fixing the road. This time, we were invited to join his guests for tea and cookies in the gazebo when we finished. It was very welcome after the long walk in the hot sun. While we were having tea, our driver showed up. They had finished fixing the road sufficiently for our van to come up. The next people to visit for servicing will appreciate that. We ended the day servicing BN03 as B4 was also
having important visitors at the tea garden. We got back before the others and then went for a final dinner together.
The next morning, Humayun, Alissa and I headed to DUET in Gazipur, where we started this trip. We met Jim’s team and put all the empty boxes into storage. Then we dropped Jim and Alissa at the airport, while Chris and I dove into Dhaka. My first time here this trip. We have the final station to install in the morning and then we fly out the next
day. Nano and Paul and Sanju will do geology for a few more days then meet us in Dhaka. Nano flies out with us, Paul heads to India the next day. Céline will continue to stay in Srimongal doing a gravity survey with Karim for the next week.
The last station is south of Dhaka between the Dhaleshwari River and the Padma, the combined Ganges and Brahmaputra. It is at a health service complex. We met and had tea, then
looked around the grounds for a good site. The first were vetoed as not secure. Too many drug addicts near the clinic. Finally we found a good spot in the open near some people’s homes, including the night security guard. It went quickly and in the middle they climbed a tree and got us some fresh green coconuts. Coconut water is very refreshing on a hot day. We finished, but not earliy enough to visit the Padma. We still had to store the remaining equipment at Dhaka University. It has been a very successful
trip. As is my experience here, people find a way to get done what needs to be done. It is a country that is resilient out of necessity. We have installed 6 GPS, 28 seismometers, Céline is getting gravity measurements that have help up a project, and Paul has at least one good geological transect across an anticline with a few more days of work. Some of us have been working together for years, but others are new to our group and Bangladesh. Over 3 weeks in the field together will help change us into a team.
I spent two more days with Jim’s team. The first day we went to scout two of the sites and then install one that was already scouted. Humayun had sent a team of students out to scout the 28 seismometers we were installing, but some of the sites were good and some were not. B11 was too close to the highway and without an out of the way place with a good place for a solar panel. After tea and fruit, the owner walked around the village with us and we found a better site. It was at the edge of a yard next to the cow shed and at the edge of a slope. The family was ready to host it
there, so we moved on to Scout B12, the one site that was not scouted. I could see there were no roads to where I have located the site. I chose a new place as we tried to drive to it. We went as far out on the road as we could drive and started talking to people. We met the local chairman and walked around with him. There were a couple of larger, more elevation homes and we went to one and discussed it with the family. They were positive, but would make a final decision tonight.
We went on to B13, already scouted, to
install. It was on the other side of the Meghna River. We unloaded our gear and got ready, but the family backed out. He thought the installation was for 2 hours, not 2 years. We went looking for a new site. First locally, then driving a little farther afield, then as a school but we struck out. It was the end of the day and we have not put any seismometers in the ground.
The next day was better. In the morning we went to install B11. When that was
done we decided to try a different road for B12. We went out on it as far as we could and beyond that point there were no homes. We turned around and stopped at every house to inquire about putting a seismometer there. Actually, Sam did and without speaking Bangla, there was little we could do. Some weren’t interested or scared of the equipment, some had no good location. After about a half dozen homes, we waited outside one promising place, but the owner wasn’t home. Finally his brother said we could put it at his house.
Not quite as good, but it was a bird in the hand. That night Humayun and Sanju arrived with Paul, who flew in to see the geology on the way to NE India. After dinner, Paul and Sanju went east to join the other team, while Humayun joined ours.
The next day, Jim, Chris and Sam went build a fence at B11, while Humayun and I went to scout. I felt that with the problems both teams were having as some sites, we might not be able to finish
on time. Adding a third team for scouting would help save time and let the other concentrate on the actual installations. We went to the government building for B10. When it turned out to not be good, we went to the local chairman and he ended up offering his house, an excellent site. Then it was time for B13 once again. We tried on the other side of the Old Brahmaputra River. The Brahmaputra shifted about 60 mi west of here about 200 years ago leaving a smaller river and a broad low area with rice fields and
brick factories. We took smaller and smaller roads, ending in a heavily rutted dirt road. We saw a government building that looked good, but it was locked. We talked to the neighbor and decided to put the instrument there. Not an ideal location, but after 2 days of failed attempts to get B13, we took it and headed east to join the other seismology team, stopping to say goodbye to the team finishing up B10.
With the scouting done, we just that the installation of the final two GPS sites to do. Since we started drilling the hole for the antenna rod at Kalenga, we went there first to finish the installation. This time, the new road surface had dried enough for us to go over it. We arrived and went to work, becoming an experienced team for the installation. As promised, they had built us a ladder, a rickety one, but functional. After competing the job, we were surrounded by kids when we returned to the ground from the installation. We once again
handed out chocolates to all the students and teachers, had tea and went on our way.
It was still afternoon, so we drove to Chunarughat where the seismic team had just finished installing a station in the college where we reoccupied. We all had tea, some fresh pineapple, snacks and caught up. They went off to another site, while we went to scout two sites farther along that were on tea plantations. We had had problems
getting permissions as some were large corporations with headquarters in Dhaka. We headed to the first one, the Chundeecherra Tea Estate. We found the office and explained the situation. As first we were dismissed, but Sanju persisted, making friends with the assistant, who called the manager back and we were invited to his bungalow. We went there and discussed the project, and had tea and snacks. The Tea Garden and bungalow – a term meaning a house in the Bengali style – date from 1876. He
needed to confirm with his higher ups in Dhaka, but had been won over to allowing our deployment. In fact, later we received approval to place seismometers in any Tea Garden belonging to the National Tea Company.
He directed us to the next Tea Garden, although we got lost before finding the right place. While we call these places Tea Gardens, they can be miles of tea plants in every direction, major operations to run. We had trouble
finding the correct entrance. We again showed up at the manager’s house and were welcomed with tea and snacks. Sanju did his magic again, making friends and persuading him to allow us to install the seismometer at his bungalow. This tea company is privately held and the manager gave approval pending confirmation with the owner, his uncle. A productive day.
The next day we went back to install the last GPS station, again bringing chocolates for the students. The drilling was slow as the concrete was hard and the batteries didn’t last. We sent our driver to recharge them at the nearest town with electricity.
He went with the principal on his motorcycle. After finishing the job we took our last group photos and had tea and cookies with the teachers.
Again we went to stop at a Tea Garden for permission. This was at Finley’s a large multinational company. We were turned away at the gate. Sanju did not give up. He persisted and argued with them for a long time, although it seemed fruitless. He then tried going above them calling the local chief of police and elected representatives. He would not give up. Eventually the assistant manager came out and spoke to us. We explained our situation. He had previously spoken with the scouting team. He agreed that we needed to speak to the Chief
Operating Officer of Finlay. He would be in the next morning at 9. We had succeeded in getting out foot in the door thanks to Sanju’s determination. And with all of the GPS stations completed, we could turn our full attention to scouting the seismic stations for the one day before Keith leaves to return to the U.S.
The next morning we arrived and were let through the gate. We drove to the COO’s office and waited until he was free. Again we explained what we were doing, reassured him, as the others that the seismometers only listen to earthquakes from around the world. They do not interfere with anything or cause earthquakes. His concern was not being able
to provide security to watch the instruments, but we reassured him that we usually left them unattended. He tentatively agreed pending some paperwork. We headed to the offices of the managers of the individual Tea Gardens we would be installing in. We drove past miles of tea to the first. When we showed the manager to location, he pointed out that it was not in Finlay’s but another Tea Garden beyond their property.
We headed off farther into the hill. The roads got progressively worse, although the road cuts showed some good geology. Finally, we hit a rut we could not drive through and walked the last mile. After waiting for him in the gazebo to finish his shower, we again had tea and snacks. We got an agreement and chose a site in his yard next to the satellite dishes (after reassuring him it would not affect reception). Another site successfully done. We walked back and then got a ride the last part of the way
from his jeep, carrying the head of another tea company. We drove to the other site on Finlay’s property, but the manager was not home. He would be back in 2 hours at 4. We left and went to pick up some gift bags of tea that Sanju’s father had left for us. It was on top of the next anticline. After several wrong turns, and more cups of tea, we got our packages. It had only taken an hour and a half to get there. On the way back, we got a call from the manager, he would meet the COO tonight to discuss the seismometers, so no need to come today. We had done what we could today. This part of the trip was a success.
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.
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.
We headed to the next area. One of Humayun’s students scouted for a location and found a reinforced concrete building, but it was not on the anticline as I wanted. It was farther west on the flatter land adjacent to the hill. It was on the wrong side of the rice/tea transition. We met the owner of the property and he accompanied us as we searched for another place. We could see why he stopped. Farther on the driving was more difficult and the houses were all thatch and tin. Walking around, we were shown a reinforced concrete building
under construction, but it wouldn’t be finished for two years. We kept hunting and then we found it. There, in a clearing, was a brightly colored primary school. Again, the headmaster quickly agreed to let us install the GPS on the roof. I even was presented to the classes. The students are a mixture of Bengali, Khasi and Garo. The later two are groups that are mainly in the eastern and western Shillong Plateau (Meghalaya). We are finding that many of the villages in the hills are part of the 2 percent of the non-Bengali population of Bangladesh. The Bengalis like the plains and rice farming, the others are hill people growing other crops. The Khasi here are Christian, we passed a church on our way in. Later we met their tribal leader.
This time a short ladder was found, allowing us to climb to the ledge over the window and then onto the roof. Much easier going up than going down
with the roof overhang. We again went to work, drilling holes in their roof and mounting the antenna, the solar panels and chaining the receiver box down for security. They had no electricity so we had to use the cordless drill until it ran out of power. Then we had to send our driver to the closest village to recharge them. Meanwhile, they served us tea and cookies on the roof. We couldn’t quite get the antenna rod as far in as I like, but plenty for stability.
The next day we had another site in a building that was too far from the hill. Again we went forward into the hills. This time, however, there was no local school. One of the Khasi villagers showed us around, but even the open fields had too many tall trees around. The best we could find was the corner of the rice of our guide. He would sell us the little plot of land we need, but it would be expensive since it would permanently removed it from productive rice farming. Sanju pointed out that there were some
Manipuri villages to the south, so we went back to the main road to try them. We discovered the maps of the area were not accurate; we failed to get to Islampur. We tried some other roads farther south. Our car could not make the direct route, so we took a detour that led us into dirt roads through a tea estate. It led us off in the wrong direction and our van was sounding worse and worse. It sounded like the CV joint was failing. We circled back to the main road on an unmapped road. We picked up someone who would show us how to
drive to Kolabonpara, our last option to the south. Beyond that is India. Again, there were no local concrete buildings. The best we could find was a newly planted field of tea. Since the tea is kept waist high, we could put the monument in the middle of the field. However, the only way to get to it was over a bamboo bridge. It would be very difficult to get a welder and generator over that. We took the name and phone number of the
manager, who was away in Dhaka, and headed off. On the way back north, we decided to make one last try by going to a village north of where we started. We got most of the way there and found a newly rebuilt section of dirt road. It was too soft for the van, so we walked the final half hour to the village. We went past the rice fields in through the beautiful woods next to the first high hill. Finally, at the end, we saw it: the land opened up and there in the clearing was another brightly colored reinforced
concrete school. Since it was Friday, it was closed, but we got the name, address and phone number of the headmaster and went off to meet him. He turned out not only to be Manipuri, but to also be Sanju’s “uncle”. With permission in hand, we headed back to our hotel. Scouting had taken the entire day, but we now had a location for the next GPS.
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.
Unlike the GPS in your car or phone that gets a location within about 10 feet, the much more expensive systems we are putting in will get daily position estimates to about 2 millimeters. To do that, they need a clear view of the sky in all directions. We have two options for mounting the GPS antennas. If we can locate solid reinforced concrete buildings, we can cement a stainless steel rod into one of the columns. If not, we can build a braced monument out of vertical and diagonal stainless steel rods driven into the ground and welded
together to make a solid base. We came prepared for either situation. The first can be done in a day, but the second requires at least two days and finding a local welder. This part of Bangladesh has the sediments folded up into linear hills where they grow tea and broad flat valleys where they grow rice. We will put six GPS devices on different parts of multiple hills and valleys.
Walking through the grounds of Lemon
Garden in the morning fog, there were no appropriate buildings and no sufficiently open space. We did find their grove of lemon trees (actually limes). We considered a hill nearby, but there was a tree at the top. As we saw later, the slopes are planted with pineapples that were being harvested. If fact, the hills here are either heavily forested or covered in tea. The tea plants are kept short for ease of picking leaves, but trees are scattered among them. We headed over to my backup for this area, a village
nearby where perhaps there might be some homes, government buildings or schools that would be suitable. As soon as we got to the village, we saw the local school. It is the only reinforced concrete building in the village. It seemed promising, but there were some trees around it that blocked the view. We met with the school officials and amazingly they agreed to cut down the trees. However, we needed final permission from the Upazila (county) Education Minister. We drove down to Srimongal, and got our permissions, along with cups of tea and cookies. It is amazing how accommodating the Bangladeshis are to us.
Our next hurdle was a ladder to the roof. When none was found, used the truck as our ladder, climbing onto its roof and then the building’s. It was now the afternoon, so we quickly went to
work, drilling an 18-inch hole in the roof and epoxying in the rod for the antenna, assembling the solar panel frame and attaching it to the roof, and finally setting up the waterproof box that will hold the GPS, the batteries, and the modem that will send the data to UNAVCO in Colorado. While we were working, the woodcutter arrived. Sanju is an ethnic Manipuri from the others side of this hill or anticline. He used his contacts to find a woodcutter, who arrived along with his uncle and younger brother. His tools
were a machete and a rope. Because we needed two trees cut down and he needed to avoid a nearby home, he raised his price. In the end, it cost us 1400 taka, almost $17, a tiny fraction of the cost in the U.S. Part of the tree falling killed a lemon tree, so we will have to pay the owner for the loss. Sanju is still negotiating the terms. As is almost always the case, it was dark before we finished the last part, installing the grounding rod for lightning protection.
The next day, we traveled two and a half hours to our farthest site. This is a reinstallation of one that was installed in 2007. The GPS, borrowed from UNAVCO had to be returned in late 2016. That makes this a simpler installation as the rod and cables are already in place. It is in a medical clinic with the equipment box located in the birthing room. The people I had met in 2007 have moved and there is a new doctor and his family living in the clinic. Since 2007, a number of trees have grown up. We again need to have trees cut down. Sanju negotiated with
the neighbor and she agreed to cut the tree for a fee, which she will sell for the wood. The branches of another tree will be cut back once the boroi fruit, like miniature apples are collected. Lunch was again tea and snacks. Two days and two sites installed. After delays of a few more days, the seismic group finally got their equipment and started testing them as we finished the second site. Things are going well for us.
I am back in Bangladesh to start deploying equipment for a large new project. Results from our last project showed there is a large earthquake hazard here. We demonstrated that the Sumatra subduction zone, where India plunges beneath Asia, continues to the north under Bangladesh. The subduction down at Sumatra caused the 2004 earthquake and tsunami that killed over 230,000 people. Even though the plate boundary comes onshore, which is unusual for subduction zones, is it still active with the world’s largest pile of sediments, the Ganges-Brahmaputra Delta, entering it. We have designed an experiment to investigate this plate boundary across three countries: Bangladesh, India and Myanmar.
Our first step is to install 29 seismometers and 6 GPS receivers in Bangladesh. To do this, we have a team of 11 people. Most of us will be here for three and a half weeks. There are five of us from Lamont, two engineers from PASSCAL and UNAVCO, organizations that provide support and equipment to NSF projects like ours, and four from Dhaka University. Ahead of us, we shipped over two tons of seismic equipment and carried over 300 pounds with us on the plane. Thanks to a two-hour delay due to fog in Dhaka, our flights lasted a full 24 hours, and longer for the two engineers coming from Colorado and New Mexico. We then spent the next several hours at the airport getting all our luggage, getting them through the huge backup at customs from all the delayed flights, changing money, and getting local phone numbers.
At a lunch stop, four members of our team who have never been here before tasted their first Bangla food. So far, they are all enjoying it. We then arrived at the Dhaka University of Engineering and Technology (DUET), north of that city to set up our base.
When we arrived we found out that the seismic equipment is being help up by customs. Since the packing list mentions the GPS antenna that gets exact time for the seismometers, customs referred it to the Telecommunications Regulatory Commission. Humayun went back to Dhaka and spent the day there dealing with it, while Alissa and I tried to find the documents he needed to show the antennae only receive signals and do not cause not interference.The paperwork is slowly going through the bureaucracy and we hope it will be released tomorrow.
Meanwhile, we spent the time running around Joydebpur shopping for the materials we need. The seismologists need to build underground vaults to hold the instruments, while the GPS team needed grounding rods and wire. Most of seismic supplies were bought or ordered, so they should be ready to move out ahead of schedule even with the delay, if they get it tomorrow. The GPS team finished our shopping so tomorrow we will pack up, hopefully be able to fit everything in one van, and take off. It will be Keith from UNAVCO, Sanju from Dhaka University and myself.
When they are done shopping and testing, the seismic team will split into two 4-person groups for the installations, starting with the dense central line of stations. We will hopefully see one of them by the end of the week when they arrive in the Srimongol area, where we are going. The other team will initially work from here at DUET. These are the two ends of the dense lines in Bangladesh and they will spend the following week deploying towards each other.
Of course we had too much stuff for the van, so the truck will come with us to carry our equipment and then return to DUET. We had the mandatory meet and greet with the president of DUET. In the end, our leaving first thing in the morning stretched to 12:30. We had hoped to stop at one of the sites on the way, but instead we went straight to the Lemon Garden Resort in the hills near Srimongal. The hills in Sylhet in the northeast part of Bangladesh are covered in tea estates. There are a growing number of resorts in the hills as well. Lemon Gardens has beautiful grounds, and tomorrow we will see if there is a good spot for a GPS.
From Khulna in the SW, we are heading to Rajshahi on the Ganges River, but first we are stopping at Kushtia, Humayun’s home town. Because the road on the more direct route is supposed to have bad road conditions, we took a longer route, way longer. It wiped out any chance to get to Rajshahi in time for some fieldwork, but it did boost my districts (states) of Bangladesh visited to 40 out of 64. After many hours on the road, we reached Kushtia and out goal – jordibaja, a fried noodle snack that is only available here. Chris bought 10 500 gram bags, about 11 lbs, at the bakery that makes
the best, of course. We then had a late lunch and continued to Rajshahi where we were once again joined by a police escort. Different teams stayed with us until we left the area. After finding our hotel, we all had our first hot water shower since we left Dhaka. Living on boats is great, except for the complete lack of hot water. Once cleaned up, we went to Humayun’s sister for a delicious dinner. After dinner, the commissioner of police, a former student of Humayun’s stopped by. He suggested we visit some of the chars (sandy river islands) close to Rajshahi rather than the places we went
to other years, an hour or more drive away. Chris and Dan checked their satellite images and found that the nearby chars would work, probably saving 2-3 hrs of driving.
The next morning, we headed off with out new escort, that included two policewoman. However, that had to switch off when we crossed from one precinct to another. Renting a country boat we crossed the Ganges to the chars. While Dan and Chris (with Humayun) made salinity, moisture and spectroscopic measurements, Liz and I
scouted for the proper sediment samples for her OSL needs. After wandering about the island we found what she wanted and collected a sample. Until now, her studies of the delta did not have any samples from the Ganges itself. For Dan and Chris to get the observations they wanted, we visited several chars before ending up back at the first one for them to study the transition from sandy sediments to rice fields. As soon as the chars have deposits of the right kind of sediments, people start planting crops. If the char continues
to grow and stabilize, they will move there as well. They are great places to live 9 months of the year, but a struggle during the high water of the monsoon season. The islands with migrate, eroding from one side while sediment deposits on the other. The char people have to move frequently as the chars move out from under their homes. Liz and I wandered off and found another place to sample. Now she have both a sand and a silt samples from the Ganges. It only took a few hours to accomplish the more specific tasks of this field program. When we first started visiting chars 12 years ago, we explored then from the morning
until dusk. We needed to see and explore all aspects of this new environment for us. Now, we are building on our work with much more focused activities.
Off the river by early afternoon, we drove across country to Bogra near the Jamuna River, as this part of the Brahmaputra is known. We were able to arrive around sunset, avoiding the sometimes frightening driving in the dark. For old times sake, we skipped the new hotel that was booked and stayed at the colorful Parjartan Hotel that we first used
in 2005. It is literally painted the colors of the rainbow, as well as having more character, even if everything is not quite working. This was the hotel where my room once had electric outlets of 4 different shapes, requiring every adapter I had to recharge my equipment. Now I always bring an outlet strip so I only need one adapter.
We had planned to go north to Gaibandha, but a new satellite overpass showed that we could get all the data we needed farther south at Sirajganj. We could cut out a day. As it turns out, this was fortuitious. I have a family
emergency and have to return to the U.S. From Sirajganj we could return to Dhaka, rather than stay at Tangail. Chris and the others can do the rest of the field work as day trips from Dhaka. It is more driving for them, but will enable be to catch the evening flight back to the U.S. We packed up and headed to the embankment at Sirajganj, which protects the city from the shifts in the Jamuna River. We walked down the embankment (the river level is about 7 m or 23 feet higher during the summer monsoon season). We headed for a large char that
we first visited in 2005. It has grown and become attached to other chars. It also has much more agriculture, they are growing rice, peanuts, lentils, corn and more. The complex history of changes in the char provides lots of different sediment types for Chris and Dan and plent of cut bank surfaces for Liz to get a good silt sample. A few hours of exploring, sampling, measuring and we were done. Since it is Friday, the Muslim holy day and the weekend here, traffic is light until we reach Dhaka. Near the university and our hotel, the streets are packed with people and rickshaws. Still we manage to get to the university to drop off equipment and for me to get 7
GPS receivers that finally have to be returned to UNAVCO after 10 years. This is the last of the 11 we were lent in 2007 by them. They provide geodetic data and services for NSF and allowed us multiple extensions that enabled us to get this much needed data for so long. It is the basis for our paper on the potential earthquake hazard in Bangladesh as we can see the slow motion of the surface (0-17 mm/y) that indicates the buildup of strain in the earth. Then back to our hotel to meet Dhiman and have a final dinner together before an Uber takes me to the airport. I am leaving to return
home, while they will carry on without me a few more days. They will visit the confluence of the Ganges and Brahmaputra Rivers, and the Padma, as the combined river is called. For me, my main goals for this trip were accomplished.
My critical equipment repairs were now done. Chris and Dan still had several days of work in the area, but Humayun and I were interested in traveling to Hiron Point near the coast in the Sundarban Mangrove Forest. We want to take advantage of being so close. We hoped we could do it in a day, with the tides and broad open channel to the south, it would take two, too much for Chris to spare. We worked out that Humayun, Liz and I could take Bachchu’s smaller boat, the M.B. Mowali. Mowali are the honey collectors in the Sundarban and Bawali are the wood cutters.
Before we leave, we have one day with Chris and the others. After, Matt and Tanjil, our forest guide from 2015 who stayed with us for a day, departed, I went out with them to Polders 32 and 31 for their afternoon run. They are making soil salinity measurements to see if it is possible to determine soil salinity from satellite imagery. Saline soils are a large problem in this part of Bangladesh. We took the country boat to shore and scouted for the appropriate place. At each one Chris and Dan laid out a grid of probes to measure salinity and moisture
content. Kingston and Zahan did similar measurements at the surface and at the root level. As always, we attracted a crowd of onlookers curious as to what these foreigners were doing.
Later, after dinner, the M.B. Mowali arrived and our group split once again. We traveled to the edge of the Sundarbans that night, to pick up our guide and our armed guard for the tigers. The Mowali is much smaller. I
haven’t seen her since she was renovated. Now there is one cabin, which Liz got, and a larger room for Humayun, myself and our guide. In the early morning we headed south. Once the fog lifted and we entered smaller channels, we started seeing deer and monkeys on the banks and in the forest. We stopped in a small side channel and had lunch before crossing the over 10-km wide estuary in our speed boat, a 40-min. ride. I could see that a lot of fresh land had grown at the mouth of the channel with the forest station and our GPS since the
last time I was here, two years ago.
We brought along lots of extra equipment in case anything had broken down. Humayun and I worked on downloading the GPS data while Liz and the guide went for a walk and climbed the observation tower. They got to see deer, wild boar and a monitor lizard, while Humayun and I sat in a dark room. As usual, we struggled to remember how to connect and download data exacerbated by unfamiliarity with the Windows OS on the PC we were using.
Eventually, we got it right and were happy to see that the system was working perfectly, with data files for every day since I last visited. Obviously, because we had brought all the equipment along, we didn’t need it. We downloaded all the data and then changed the SIM card in the modem. We had set up cellular communications when we installed the station, but the signal was too weak to collect any data. Now there is a good signal here from a different cell phone company. When we get back we will have UNAVCO check to see if it works. In any case, we now have enough data to measure the subsidence here. The sinking of the land exacerbates the impact of rising sea level. Only the vast sediment supply of the delta counters it to maintain the land. And that is at risk from human intervention.
We had tea and cookies with the forest ranger and then headed back before low tide trapped us in the channel. As things went well, we stopped on the newly emerged char land and Liz and I walked around examining the sediments, surprisingly sandy for a tidal estuary. Back in the speed boat, we crossed the broad channel and then paused to watch the sunset on the water. Once on the Mowali, we sailed to where we would spend the night in the Mangrove Forest, and now I got to see deer and boar on
the way before darkness descended. There was even a herd of nine or 10 just across from where we rejoined the Mowali.
In the morning, we started heading north. Because it was very foggy, we stayed in smaller channels for a few hours before entering the main channel of the Pussur River. I spent the early morning before breakfast watching the forest go by and spotted a few more
deer. By noon we were out of the Sundarbans and ready to drop off our guard. I actually hadn’t seen him for the entire trip. We continued past the Rampal power plant. This is a coal-fired plant being built less than 20 km from the Sundarbans. Most of the coal for it will likely be transported up the Pussur River through the Sundarbans. It is the subject of a lot of protests, including the hartal we had last week, but they are not likely to stop it from being built. A short time later we met up with the Bawali and
moved back across. Then, work here being done, both ships sailed up to Khulna for the night. Tomorrow morning we disembark for the next phase of the trip.
After a night in Dhaka, our group temporarily split up. Chris and Dan headed to Khulna in the SW at 4 a.m. to avoid the hartal (general strike) that was planned for 6 a.m.-2 p.m. Liz and I stayed in Dhaka for a day. I spent it mostly editing material for a new project. The next day, Liz, Humayun, my partner from Dhaka University, and I followed the others to Khulna, crossing the Padma (combined Ganges and Brahmaputra) River by ferry at Mawa. After waiting an hour, Humayun used a connection from a former student to get us on the next
ferry, a fast one. It is impressive how much the river has silted up since the last time I crossed here. Another few hours and we arrived at our compaction meter site SE of Khulna. We picked up one of the four sons from the family that takes care of the site. Mofizur, the second son, now a student at Chittagong University, is returning home for the first time in six months. Making the weekly measurements has been passed along from the oldest to youngest sons. It made for a great welcoming by the Islam family when we arrived mid-afternoon.
The last time I was here, the river adjacent to the site was being dredge and widened. It had gone from 200 m wide to just a few and was now too small for boats except at high tide. The widening cut into the bank that held our instruments. While the engineer tried to leave us enough room, it clearly didn’t work. The pillar that holds the GPS antenna is tilting badly towards the stream. They have secured it with ropes to keep it from completely falling over. We got hold of a ladder and removed the unusable antenna. Mofizur climbed up, afraid that I weighed too much for the fragile system. Next, Humayun and I surveyed the monuments for the compaction meter wells. We had to dig out the sediments
covering the base. Liz measured the thicknesses, which were 4-7 inches. We could clearly see the finely layered sediments deposited from before the river was enlarged to the thick muds that accumulated afterwards. The sedimentation rate had clearly increased due to the river widening. The survey will give us the relative heights of the wells. When we get back we will compare it to earlier measurement to see if the wells have shifted, too. Without the GPS we cannot determine the absolute elevations. Our last task was to measure the lengths of the optical fibers in the wells. We brought along a new laptop to work with the electronic distance meter (EDM), but we found the recharger was still in Dhaka. We had forgotten it. With a dead battery and no way to recharge it, the measurements will have to wait until Humayun can send the recharger.
While we were there, we were served lunch, a huge banquet. Three kinds of fish, chicken, rice, vegetables, two desserts. The three of us sat a table outside in the yard, while the family plied us with the delicious home-cooked Bangladeshi food. The more important the guests, the more food, and were were suitably overwhelmed. And since it was after 3 p.m., we were famished and did our best make a dent in it. Since the GPS is no longer usable, we left them the battery and solar panel that was powering it, doubling their electricity supply. Before we installed the
equipment in 2011, they did not have electricity at all. After some heartfelt farewells, we headed to Khulna to meet up with Chris, Dan and Matt Winters, my teaching assistant from the class I taught in 2015. Fluent in Bangla, he has been working with Chris on field observations for his master’s thesis at Columbia. He and some of his assistants will join us for a few days. The three of them had a dinner meeting, so my group headed to the M.B. Bawali, our home for the next four days. Smaller than the M.B. Kokilmoni, it is a perfect size for our group.
The next morning, we headed for Polder 32, the embanked island we have been studying. Humayun and I will visit the GPS station we set up there in 2012. It has a cellular modem so data can be downloaded remotely every day, but stopped working in November. It seemed that the receiver was not recording satellites, so we brought along replacement antennas, cables and lightning protectors. Another GPS station had a similar problem, and there the cable had to be replaced. When we arrived at the school, we found the receiver was tracking satellites. We didn’t
have to track down a break in the system. But why wasn’t it recording data? The best we could ascertain was the modem had hung up; rebooting it fixed the problem. It was working, but I don’t understand what happened enough to be sure it won’t happen again. Hopefully, now that it is working, the engineers at UNAVCO can log in and work on it. When we double checked everything, we found that the grounding wire was missing. This is unsafe. If there is a lightning strike, the lightning protector blows the connection
to the equipment inside and shunts the electricity down the grounding wire. We cannot put a school full of children at risk. The only wires we had were the coaxial antenna cables. We stripped the ends off a partial cable and wired it between the cut ends on the roof and near the ground. We made a visit to the Hindu goddess of education and headed back to the ship having done all the repairs we could, and satisfied that the school was safe.