Earth Sciences in Jamaica

During J Term 2013, nine students are traveling to Jamaica as part of a multidisciplinary Earth Sciences course to conduct geophysical research on earthquake risks on the Caribbean island. Jamaica’s capital city of Kingston rests precariously along the western edge of the Enriquillo-Plantain Garden Fault, which activated in the catastrophic 2010 earthquake in nearby Haiti. During their trip, the students will collect and analyze geophysical data on land and at sea, and will present their findings to Jamaica’s Office of Disaster Preparedness and Emergency Management. Taught by SMU Earth Sciences Associate Professor Matt Hornbach and Lyndon Brown of the University of the West Indies, the course is funded in part by the Society of Exploration Geophysicists’ Geoscientists Without Borders program and The Institute for the Study of Earth and Man in SMU’s Dedman College of Humanities and Sciences.

Our final day in Jamaica

The SMU group and Mr. Stewart (left), our fearless driver. The white rocks in the background show the headwall of Judgement Cliff, a massive landslide that occurred during the 1692 earthquake. The white cliff face is nearly a half-mile wide. When the slide occurred, it buried a plantation and all of its occupants.

An update from Emma, a geology and mathematics major:

Emma taking a break along the eastern shore of Port Royal, with Gun Cay and Lime Cay in the background.

I woke up on our last day in Jamaica at 7 am to finish my final paper. I was in the sediment group, and we analyzed the sand on the beach to determine its angle of repose, porosity and density, with the ultimate goal of determining the probability of slope failure in and around Kingston Harbour.

One of my jobs was to conduct a statistical analysis on all of the data we collected. I calculated the mean, standard deviation and coefficient of variation for the angle of repose for sediments of varying water content.

At 8 am everyone ate breakfast, then packed up to return to Kingston for our final night. On the drive back, we stopped in Yallahs for some traditional Jamaican Jerk and continued on to Judgement Cliff. The cliff was created in 1692 by a landslide caused by the same earthquake that destroyed Port Royal. It is an enormous landslide.

When we arrived in Kingston we dropped off our seismic and surveying equipment at the University of the West Indies campus, toured the Earthquake Unit where Lyndon works and then went to Usain Bolt’s restaurant, “Tracks & Records,” for dinner.

Connor attempting different grain-size and angle of repose measurement techniques.

After dinner we all listened to Brett and Gwen’s presentation. They were part of the surveying team and had integrated our angle of repose results with their surveying analysis to assess slope stability at Port Royal. In their presentation they came to the preliminary conclusion that only a magnitude ~5 earthquake near Kingston is necessary to cause slope failure in Port Royal. Further analysis is necessary, but their conclusion – based both on experimental and theoretical data – closely matches historical observations.

I have had an amazing time in Jamaica and learned so much. I am on the 730 flight back to Dallas, so I will be in bed early!

 

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A full day of work: Assessing slope failure in Port Royal

An update from Ben, a second-year graduate student in Earth Sciences:

Beep.
Huh.

Beep!
What?

BEEP!
Fine!

And thus the day began like any other day, with me waking up early, of course!  After my breakfast of a Jamaican delicacy, pancakes, we began our work for the day.  Unlike the past week, when we collected at least some field data each day, today was a full day of processing and analyzing the data we have gathered throughout our past surveys.

Connor, Zach and Emma working up the final Port Royal angle of repose report.

We have the sediment group – we shall call them the “dirt people” (it is not geologically correct but go with it) — who were cooking mud pies and making sandcastles in the corner. The mud pies turned out a little dry for my taste, but the dirt people seemed to enjoy the final product.  The sandcastles never got very tall.  They seemed to be having a problem getting their castles past an angle of 40 degrees (they were completing angle of repose calculations for Port Royal).

The surveying group worked on at least three different tables through the morning.  I am not sure why they tended to move so much; I guess they just got used to traversing across the landscape so much during their data collection and are now uncomfortable staying in one place.  They finally settled into a routine of combing through data to generate slope maps to compare and integrate with experimental angle of repose data provided by the “dirt people.”

Lastly, the seismology group, I dub them the “knuckleheads” (this would make sense if you met them), who disappeared into the depths of the hotel to continue their analysis on seismic data collected the past week.  They seemed to avoid the room with the other students and the shining sun.  I attribute this to their affinity for collecting data while in the shade of the surveying boat.  The sun is just too much for these people.

I was on trouble-shooting duty for those with limited programming/modeling experience. I helped generate digital slope maps with the surveying group, and taught the knuckleheads to work different seismic software when needed.

Presentations on the veranda in Morant Bay.

After a break for a dinner of goat (yes, I am serious), we proceeded to our classroom, a patio overlooking the Caribbean Sea, to see student presentations from today’s analysis projected on a whitewash wall. With the ocean in the background, the student-lead presentations began.  Each group learned from the others about different but interlinked aspects of geology and geophysics from the different surveys.  I do not believe a single person left without learning something new from the other groups.

All of the groups worked very hard throughout the day preparing, processing, and analyzing the data, and it clearly showed in tonight’s presentations.  I am lucky to be part of such a driven and bright group of both graduate and undergraduate students!

Gwen, Austen and Brett take a break to catch the sunset over Morant Bay before evening research presentations.

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A day of collecting seismic data

An update from Zach, a graduate student in geophysics:

“Cheen”, our first mate for the Port Morant shallow water survey on Day 7.

After a morning cup of coffee with fresh fruit at 7, we got the seismic chirp gear loaded into the car and sent off to Port Morant with Ben, Joey, Dr. Hornbach and Lyndon.  I then returned to the dining room for breakfast with the rest of the group.  The highlight of the morning was trying out the traditional Jamaican dish of Ackee and Fish.

While most of the group remained at the hotel for the day to process data collected earlier in the week, Conner, Gwen, Bret and I headed to the port to meet the boat and collect seismic data.  The port is roughly 1 x 2 miles in size, with beautiful blue-green water. The east side of the port has steep tree-covered cliffs, and the rest has low 10-foot rock outcrops.  To the north and west, the green John Crow Mountains dominate the landscape.

The after-dinner presentation: Cliff presented preliminary interpretations and results from the seismic survey completed on Day 5.

Our boat is a 20-foot fishing boat with long bamboo poles on both sides for fishing nets.  Today there were no nets; only our makeshift chirp system artfully set up by Joey and Ben prior to our arrival.  Making our slow tracks back and forth, we collected data over most of the port during the day. During our survey we viewed the data in real time and made some interpretations about what we were seeing and what it might mean in context with the geologic history of the area.

After collecting data until we were out of power (5 hours), we headed back to the hotel to clean the equipment, transfer and back-up data, and shower and dinner.  Dinner didn’t disappoint, with bowls full of roasted chicken, rice and beans, and vegetables.  It was all topped off with an amazing juice concoction of fresh local fruits and ginger.

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My Jamaican experience

Traveling through the jungles of Jamaica.

An update from Joey, a senior geophysics major and math minor:

Austen on the beach as others body surf.

After several long days of hard work, we decided to play tourist for most of the day. We woke up this morning, packed up and checked out of our hotel in Kingston. We headed north over the Wagwater Fault and into the Jamaican jungle en route to Port Antonio on the Northeastern Coast.

It was awesome. Around every corner a new surprise met us. As our bus driver played his CD of Bob Marley’s Best Hits, we traveled past bamboo forests, steep cliffs, giant boulders, palm trees, winding rivers, and small local villages, which kept all of our eyes glued to the windows.

As we traveled I could not help but think how lucky I am: We were passing these villages that consisted of nothing but shacks made out of anything that the locals could find. I’m talking cinderblocks on top of a section of tin roof to keep it from blowing off. Many villagers seemed to roam the streets as if there was nothing else they could be doing.

Although some of these towns appear to present little opportunity, we did not talk to one Jamaican in these towns who wasn’t upbeat or in a good mood. All were very prideful and seemed to embrace the phrase “One Love” that has been on virtually every other street sign or advertisement that we have passed. It makes me so thankful for what I have and the opportunities that are given to me.

Dr. Hornbach photographing a Hermit Crab walking across his laptop.

As we went up and over the next mountain range, we were greeted by St. Mary’s Banana Farm, which makes St. Mary’s Banana Chips, which have become the students’ favorite snack this week. We continued through the banana forest, ended up in fields of pineapple and eventually on the northern coast. We headed east to Port Antonio.

Joey drinking a coconut he and Cliff pulled out of a tree

After being given a blessing of “Peace, love, unity, brothers and sisters, we are all one people,” by a Rasta man, we found ourselves on a white sand beach between two cliffs at the mouth of a river. Ben and I headed straight for the rocks, where we hiked up, over, and through the limestone as the waves crashed around us. We headed back to the beach, where the rest of the crew had already discovered the rope swing hanging above the river. Once the rope swing got old, we took to the waves and attempted to body surf.

Cliff, Connor and I headed off on a quest to pick our own coconut. It was a success; we got our coconuts. Not only did we get them, but we popped a hole in them and drank the milk… yeah, we’re awesome.

After a couple of hours at the beach, we all got back in the van and headed for lunch. Lyndon, a UWI professor who has been co-leading the study all week, took us to a small village famous for its local cuisine. It consisted of a bunch of really cool, small, open-aired shacks with the locals preparing the food over open fire pits. We were in for a treat. We feasted on Jerk Chicken, Jerk Pork, Jerk Fish, Jerk Lobster, Yams, Festival Bread, and an assortment of local fruit juices that none of us had ever heard of. We were stuffed!

Lining up for local cuisine

We continued on to our next hotel but made one more stop. We pulled off near Holland Bay to take our best look yet at the fault line between the Caribbean Plate and Gonave Micro Plate, which is the reason for the island’s formation.

Finally we arrived in the quiet town of Port Morant, where our next hotel is located. We settled in and discussed our plans for tomorrow as we were served another amazing local meal of shrimp and rice.

We were told by Lyndon and Renee, a UWI grad student, that we were basically experiencing what it’s like to be a local. Nothing that we were doing or seeing was in an area where tourists usually go. I find that very cool. Unfortunately our day of exploring is over, but I am looking forward to what tomorrow has in store.

Sunset at our hotel outside Port Morant, our next field site.

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Piecing together Kingston’s Tectonic Puzzle

An update from Cliff, a first-year master’s student in Earth Sciences:

Cliff collecting seismic data in northeast corner of Kingston Harbor.

Today was the last day of fieldwork in the Kingston Harbor, and I got to spend it surrounded by blue ocean and lush green mountains.  At 8 a.m., our trusty driver, Mr. Stewart, arrived at our hotel, ready to haul us over to the UWI Marine Laboratory again.

We loaded all of our seismic gear onto the boat and headed out for a long day of data collection in the harbor.  Today, we were focusing on mapping out what we believed to be a strike-slip fault running northeast-southwest through the harbor, along the southern edge of the city of Kingston.

We got our system up and running, and deployed it into the water in no time flat, compared to our first excursion. It was the calmest we had seen the waters since we arrived, and we were looking forward to seeing high quality data. We also got a chance to show off our chirp seismic imaging system to our new friend and colleague, Renee, a native Jamaican who will be spending the spring semester at SMU as an exchange student working on some of these data as part of her master’s degree.

Students prepping for field work with Hugh (the UWI science officer) at the UWI Marine Lab in Port Royal.

With the gear deployed, it was a simple case of shooting as many seismic lines as we could cram into the day. For every pass we made across the harbor, we pieced together another small but important part of Kingston Jamaica’s geology.  Our preliminary interpretation from what we saw during data collection is that an old but possibly still active fault extends across the harbor in a northeast-southwest direction. Further analysis of these data will clarify this, though.

It was a great feeling knowing that by the end of the day, we would have enough data collected to begin piecing together the puzzle of how Earth’s tectonic forces shaped the area and how they might continue to shape the landscape of Jamaica for years to come.   After a long day under the Jamaican sun, we said our goodbye to Donald, our amazing boat captain who had been such a helpful guide the past three days.

Joey interpretting chirp seismic data he collected two days ago.

After a much needed dinner break, we listened to a 30-minute power-point presentation given by Emma and Joey, who spent the entire day analyzing and interpreting seismic data we previously collected on Day 3 of the study.  Now, I’m looking forward to a restful night’s sleep, a new adventure, and a new side of Jamaica tomorrow!

Emma and Joey presenting their initial analysis and results from the Day 3 seismic survey.

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Coring in East Kingston Harbor and a visit to Giddy House

Our group at the University of the West Indies’ marine campus building at Port Royal.

An update from Gwen, an engineering and Spanish major:

Gwen (left) and Emma on an anchor at Fort Charles Port Royal Museum.

Today, I woke up and rolled out of my super-cushy new bed at 7 a.m. Bleh! The earliness of the morning was quickly ameliorated by the delicious Blue Mountain coffee that was served at breakfast in the hotel, along with fresh papaya and a salted fish dish.

The 11 of us packed up the seismic chirp gear, the surveying gear, and the multiple strange long rods, kits, etc. into the bus. We then headed out to one of the University of the West Indies’ coastal labs, accompanied by Renee and Lyndon. The bus ride offered beautiful views of the Blue Mountains and the fault line that we are researching.

A sediment core collected in eastern Kingston Harbor that shows tilted bedding. The core site is in the shadow of Long Mountain, which plunges steeply into Kingston Harbor and may be tectonically active. We will use cores to help constrain deformation rates and the probability of a large earthquake.

Once at the West Indies lab, we headed out in a boat to see what the different groups (surveying, soil coring, and seismic) could do. The soil-coring group was surprisingly successful in an area near the fault line. Unfortunately, the sea was too rough for any of the other groups to get much done, and we spent a lot of time bouncing up and down in the boat, buffeted by waves, kind of like a theme park ride. We saw sea turtles and lots of jellyfish.

After a delicious lunch of Tastee Cheese (a Jamaican delicacy – cheddar cheese that comes in a can) and bread, we moved our group to Fort Charles. Fort Charles was built before the first recorded major earthquake in Jamaica in the 1600s, so it was very interesting evidence to check out.

Gwen helping hold up Giddy House.

At right is a picture of me leaning on Giddy House, which was tilted about 45 degrees sideways during the 1907 Jamaica Earthquake. Pretty cool! After a delicious dinner and some data input, it’s time for bed.

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A long day collecting 15 kilometers of seismic data

An update from Austen, a junior majoring in geophysics: 

Austen interpreting seismic chirp data real time in Kingston Harbor.

My day started at 6:30 this morning before the sun was ready to go. After our Day 2 issues with the GPS, we were finally ready to start collecting seismic data.

We headed out to meet Donald, the University of the West Indies boat captain, at the dock and set out for the southern end of Port Royal spit with all of our seismic gear on board. Upon arrival at the location, we set up the chirp system as we had the previous day, with a few modifications.

The first hour was spent surveying sand deposited by long-shore drift adjacent to the shipping channel along the southern edge of the Port Royal spit.  After completing several lines, the wind and seas picked up, and we had to pack up the system and head to more sheltered water in eastern Kingston Harbor. Once we arrived at the eastern side of the harbor, we set up the chirp system again and started surveying the eastern end of the Kingston harbor, where evidence of recent faulting exists.

Brett measuring beach slope angle change along Point Royal’s east coast.

I spent the next few hours analyzing the seismic data real time on our computers, searching for unconformities and tilted bedding in the subsurface. After a few lines were shot, I was able to notice what appeared to be a river basin that had once flowed through the region. I then asked Cliff to start marking GPS points to map out the bottom of the basin so that we could later shoot along the axis of the deepest part of the channel formation.

Around 2:15 we finished collecting seismic data at this site. We pulled in our gear, packed up our equipment and headed back to Morgan’s Harbor to clean the equipment and get ready for dinner and meetings. Following a fantastic jerk chicken wrap, we sat down and worked on downloading and updating our seismic data and prepared our nightly report. We then prepped for tomorrow’s seismic collection and processing.

Unloading seismic and coring gear at Port Royal Dock.

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Gathering data on land and at sea

An update from Connor, a junior geology major:

Renee analyzing beach slope and angle of repose analysis near Port Royal. A graduate of the University of West Indies, Renee will start a research sabbatical next month as an exchange graduate student at SMU.

Today was day one of data collection out of Morgan’s Harbor. Three groups set out for the bay, the beach and the mangrove swamp to make measurements assessing tectonics, paleoseismology and slope stability.

I spent much of the day working with the coring group. This entailed collecting data both on land and at sea. On land, we bushwhacked through the thorns to reach mangrove ponds.

The coring group encountered many interesting locals while trying to enter the mangrove. The mangroves resisted entry and failed to yield good cores when we reached the water.  Thick mangrove roots and deep water are to blame.

Evidence of a former high-energy channel was also discovered as we walked the beach-mangrove border. Better cores were acquired later in the day by boat in the mangrove swamps northeast of Port Royal. Analysis showed extremely fine black sediment in this area.

From left: Connor, Joey and Zach collecting sediment cores on a University of West Indies research boat in a mangrove swamp, northeast of Port Royal.

The slope stability survey group on the seaward beach initially experienced technical difficulties but ultimately succeeded in gathering high-quality elevation data. They were visited by wild dogs who dug a large hole near them.

Joey and Austen deploying a chirp seismic imaging system over the side of a boat.

The seismic imaging group collected seismic lines in the eastern portion of the harbor. However, part of this study suffered from a GPS that would not update, and students spent much of the afternoon fixing this issue (it now appears resolved).

A good day was had by all, and data gathered is looking to prove useful. Sunburns forming on many.

Sunset in Port Royal (photo by Joey F)

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Arrival in Jamaica

SMU students testing coring gear off the pier. (Photos by Joey F.)

An update from Brett, a geophysics major:

We flew into Kingston’s airport and arrived at Morgan’s Harbour Hotel in Port Royal at about 3 p.m. After a long day of flying, it was great to finally get settled into the hotel and be in the Tropics.

Cliff beside the seismic chirp system.

After a debriefing by Professor Hornbach, we divided into specific groups based on our project goals and interests for the week. These groups include a group responsible for seismic imaging, a group responsible for sediment coring, and a group interested in slope stability surveying. One key goal for this study is to integrate multiple datasets so that we can begin to determine areas prone to slope failure if an earthquake occurs. Today these groups tested equipment and methods to make sure everything worked smoothly for when the real research begins tomorrow.

After spending a few hours making sure all the equipment is functional, we had a dinner of fish sandwiches and burgers right on the water. I think the temperature was somewhere around 85 degrees; couldn’t get much better.

Ben examining seismic data display tests.

After dinner we then met back up and went over what each groups’ goals are for tomorrow and where they are going to conduct their research. We also began to record the methods we plan to use and present over the next several days.

Overall, it was a hectic day of travel and preparation, but after a good night’s sleep, we will all be ready for the days to come.

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