Subduction zone mechanics

Ancient Faults & Water Are Sparking Earthquakes Off Alaska

Ancient faults that formed in the ocean floor millions of years ago are feeding earthquakes today along stretches of the Alaska Peninsula, and likely elsewhere, a new study suggests.

by |November 16, 2015
The drillers insert the larger diameter 4" PVC pipe into the well.  Handling the 10 meter pipe is challenging.

Last Sample and Home

We finished our work at the river transect. Now we had one more sample to collect. Alamgir had arranged for drillers at this new site, but they were delayed because of a knife fight between two villages over some property.

by |October 20, 2015
Hammering the OSL sampler, which is at the end of many auger extension rods.  The sampler fits inside the 3" PVC pipe that had been installed.

OSL Samples at Last

The success of the tube wells for drilling and obtaining samples was a great boon to our field program. We drilled three additional tube wells to complete a five-well transect across the abandoned river valley. When we date the samples, we will find out if the river switched position suddenly, possibly from an earthquake.

by |October 20, 2015
Standing ankle deep in mud by the resistivity meter.  The smokestack of the brick factory can be seen in the distance.

Tubewells to the Rescue

The resistivity testing was hampered by bad roads and flooded fields. The augering was proving similarly difficult in the thick muds of the abandoned channel. It was time to change to our alternative plan: drilling with tube wells. That worked better and we had turned a corner.

by |October 17, 2015
The large abandoned channel we hoped to work in is completely flooded.

Pani, Pani Everywhere

Heading out to our field area, we discovered that the abandoned river valley we planned to study was completely flooded. There was pani—the Bangla word for water—everywhere.

by |October 14, 2015
The Taj Mahal. You can see its enormous size from the line of people waiting to get inside standing on the pedestal. The line completely circled the tomb on this holiday weekend.

Bangladesh and India, Too

Returning to Bangladesh for additional fieldwork, I stopped off in India for several meetings, but we found time for some sightseeing, too. We were able to see the Qutub Minar complex in Delhi as well as the Taj Mahal and Agra Fort in Agra. Plus all the meetings in Delhi, Kolkata and Dhaka were very successful.

by |October 13, 2015
Map of hazards data points

Mapping Tool Lets Users Pinpoint Hazards Data

The SEDAC Hazards Mapper is designed for disaster risk managers, humanitarian response organizations, public health professionals, journalists and others needing a quick assessment of the potential dangers posed by a major hazardous event or developing emergency.

Overhanging rooks and slumps reveal the much larger amount of erosion and land loss in the Indian Sundarban

Indian Sundarban

We arrived in Kolkata, and filmed by the Hooghly River. While it is no longer the main channel of the Ganges, it is still the Holy Ganges and we saw a funeral procession spreading ashes of a loved one while filming there. Then a 5 hour trip by car, ferry, rickshaw and boat to the Indian Sundarbans. The mangrove forest here is undergoing more erosion and land loss than in Bangladesh, where more river sediments can replenish it. The water here is more saline and the trees are small. A tiger was spotted by another boat, but was gone when we got there.

by |March 30, 2015
The M/V Katundu in port in Nkhata Bay, Malawi.

Mapping Faults Hidden below Lake Malawi

Marine seismic studies like ours are routinely done in the oceans using scientific equipment and research vessels outfitted specially for these purposes. Collecting comparable data in a great lake in Africa requires creative repurposing of available vessels and adaption of scientific equipment.

by |March 26, 2015

Upcoming Scientific Fieldwork, 2015 and Beyond

On every continent and ocean, Earth Institute field researchers study the dynamics of climate, geology, ecology, human history and more. Here is a list of expeditions going on this year, and beyond.

by |March 10, 2015