What’s it like to witness an impending earthquake?

Humayun Akhter inspects equipment at his site in Madhupur. (Photo credit: Jessica Mudditt)

Humayun Akhter is a seismologist who has been running the Dhaka University Earth Observatory (DUEO) network in Bangladesh since it was set up in 2003. Earthquake preparedness is a cause for concern in Asia – witness the recent earthquakes in Japan and Myanmar – especially in densely populated and disaster-prone countries like Bangladesh.

His task on the day was to visit two earthquake-monitoring stations – the first at Madhupur, around 160 km to the north of Dhaka.

During the six-hour journey to Madhupur, past pineapple plantations and through patches of the Madhupurer Gor forest area, Akhter expressed deep concern about Bangladesh’s lack of preparedness for an earthquake.

His main worry is that although the government gave DUEO permission to install seismic equipment on its property, the data is not shared with the government’s meteorology department, which lacks nationwide seismic data coverage.

“Although it’s not possible for any government to handle this alone, our government is not giving enough importance to the issue.”

Akhter believes this may be the result of misconceptions about the likelihood of a massive earthquake in Bangladesh.

“Although earthquakes do not occur frequently in Bangladesh, high magnitude earthquakes can occur in low frequency zones,” he told IRIN.

Furthermore, Akhter warns that the effects of an earthquake would be catastrophic for the densely populated capital, Dhaka, which the World Bank ranked as the world’s ninth largest city in 2010. The city is surrounded by several active faults, and it mostly lies on alluvial sediment, which makes buildings more vulnerable to shaking.

He said compliance with the national building code is low, so most buildings lack adequate foundations, and the code has not been updated since it was published in 1993.

The city is surrounded by several active faults, and it mostly lies on alluvial sediment, which makes buildings more vulnerable to shaking.

“In other nations, seismic risk maps are updated every two to three years – it’s a continuous process.”

In 2009, a study by the government’s Comprehensive Disaster Management Programme estimated that a 7.5-magnitude earthquake from the Madhupur Fault would instantly kill more than 130,000 people.

 

DUEO’s work

DUEO is conducting long-term research on plate motions and seismic activity in Bangladesh and surrounding areas by collecting data from two of the nation’s six portable GPS (Global Positioning System) stations. While the GPS stations provide three-dimensional images of plate motions, which are responsible for built-up energy in the Earth’s crust, the country’s 16 seismic stations record seismic wave forms.

Data from the six portable GPS stations is collected every two months, enabling seismologists to calculate the probability of the region being struck by an earthquake, and its likely magnitude. Although only three GPS stations can provide real-time displays of motion to network members, Akhter said the others will be upgraded to provide connectivity in the near future. In any event, DUEO must physically visit each site to conduct maintenance. To calculate and assess tectonic movement, including the location of an earthquake’s epicentre, data is required from three different sites.

DUEO is a consortium of universities working in collaboration with Lamont-Doherty Earth Observatory of the USA’s Columbia University. "DUEO operates [a] network of 6 permanent seismic stations, 6 portable seismographs and 18 continuous geodetic GPS stations in the country," says the network’s website. The government has four seismic stations, which are operated separately. It does not operate any GPS stations.

 

Theft

Once at Madhupur, which has one fixed GPS station and a portable seismograph, it quickly becomes apparent – while preparing to copy the data by connecting the laptop (a Personal Data Assistance) device to a seismic data logger – that the power supply is out.

Akhter discovers that both solar panels, worth US$1,100, have been stolen from the roof. “This seismic station is dead,” he says.

Akhter removes the memory sticks to analyse the time of theft – the second in two years. He hopes that the Incorporated Research Institutions for Seismology (IRIS), will replace the panels, but says it will take time.

Portable seismic stations (seismographs) are deployed after an earthquake. In 2008, one such device was moved from Sylhet in northeastern Banglasdesh after an earthquake measuring around 3.0 on the Richter scale along the Madhupur fault, near Tangail.

At dusk Akhter and his team (a driver and a research assistant) arrive at the Manikganj site (central Bangladesh), which has a seismograph but no GPS, to collect data and replace the power system, which involves connecting a new electronic device to the solar panel and DC battery. Monitoring seismic activity at Manikganj is particularly important, as the government has proposed the construction of a nuclear power plant in nearby Ruppur and is relying on DUEO’s results.

The team returns to Dhaka later that evening, but Akhter’s work is by no means over: Further field trips will be required to collect data from four other sites; then about a week’s work is needed to process the results, which will be sent to Columbia University and IRIS, which provides instrumental and technical support.

 

The article was first published in IRIN in April 2011.