New GSN Station Begins Operations in Tajikistan


Representatives of the Geophysical Service and
Institute of Geology, Earthquake Engineering and Seismology at the entrance to the II.SIMI station.

With funding from the Department of Energy's Seismic Cooperation Program through Lawrence Livermore National Laboratory (LLNL), the IRIS GSN recently installed a Global Seismographic Network affiliate station in Simiganch, Tajikistan (network code II, station code SIMI). The installation of the station,
and its ongoing operation, are part of a new agreement between IRIS and the Academy of Sciences of the Republic of Tajikistan. This
agreement is an important step in renewed collaboration in earthquake studies between the US and Tajikistan.

As part of a US-USSR program in earthquake studies dating back to the mid-1970s, a number of collaborative projects were initiated between the United States, Tajik, and Russian groups in Central Asia, including an IRIS/IDA GSN station at Garm and a project to study induced seismicity at Nurek Reservoir on the Vakhsh River. During the unsettled period following the breakup of the Soviet Union and a decade of civil war in Tajikistan in the 1990s, the GARM station was destroyed and much of the local infrastructure for seismic observations in Tajikistan was lost. In 2008, the Geophysical Service of the Academy of Sciences of the Republic of Tajikistan was created to develop and operate a new system for earthquake observations in Tajikistan. With initial support from the Swiss Agency for Development and Cooperation, six modern broadband seismic stations were installed using Nanometrics Libra hardware. These stations now form the core of the new Tajikistan National Seismic Network and, as part of the agreement between IRIS and the Tajik Academy, these data are openly available through the IRIS Data Management Center (network code TJ). There are plans to expand the TJ network by adding additional stations in the Pamir Mountains and surrounding the site of the new Rogun Reservoir, upstream of Nurek. The new IDA GSN station at SIMI will enhance this national monitoring system and provide high-quality GSN data of significant value for research and verification monitoring.












Nurek Dam, on the Vakhsh River in Tajikistan, is the highest dam in the world (315 m) and the location of a well-documented case of induced seismicity (Simpson and Negmatullaev, 1981, BSSA, V71, pp 1561-1586. Rogun Dam, currently under construction 60 km upstream from Nurek, has a planned height of 335 m.












Entrance to the geophysical observatory tunnel at Garm, Tajikistan. Formerly the site of the IDA GSN station GARM, it has now been replaced with one of the telemetered Nanometrics stations of the Tajikistan National Network (TJ).

The new seismic station came online on October 6, 2016. The installation of the equipment was completed over a few days by Project IDA staff in coordination with the US Embassy and local staff from Tajikistan Institute of Geology, Earthquake Engineering, and Seismology (IGEES). Equipment was transferred from storage at the US Embassy in Dushanbe via truck to the station location near the village of Simiganch, approximately 25 km NE of the Tajik capital of Dushanbe. The seismometers are installed in a chamber in a 100 m long tunnel that was dug into the mountains of the Southern Tien Shan as part of a geophysical observatory during the Soviet era. The primary sensor installed at II.SIMI is a Nanometrics Trillium 240 (a broadband instrument), and is co-located with a Kinemetrics FBA ES-T Episensor (a strong motion instrument). Data are telemetered in near real-time to the IRIS Data Management Center (www.ds.iris.edu/mda/II/SIMI). The station has also been added to the _GSN and _GSN-Broadband virtual network definitions. Seismograms from an earthquake that occurred on November 25, 2016, in Southern Xinjiang, China, are shown below.


Equipment installed in tunnel.  The foam covered box is insulating the Trillium 240 seismometer.


Farkhod Hakimov (IGESS) and David Chavez (Project IDA) measure the orientation of the seismometer.


Mounting GPS antenna.


Seismogram from the magnitude 6.6 earthquake that occurred in Southern Xinjiang, China on November 25, 2016, at seismic station II.SIMI. Top (red): Recorded by the T240 broadband seismometer. Botton (magenta): Recorded by the ES-T strong motion seismometer. Click to see larger image.