MicroSeismic, Inc. Awarded Second BuriedArray(TM) Contract in Marcellus Shale

HOUSTON, TX--(Marketwire - Apr 21, 2011) - MicroSeismic, Inc. (MSI), a leading geophysical services company today announced that they have been awarded a second BuriedArray™ contract in the Marcellus Shale play in northern West Virginia by Gastar Exploration Ltd (NYSE Amex: GST), an active independent exploration and production company focused on the Marcellus Shale.

"We are excited about our continued work in the Marcellus," said Peter Duncan, CEO and Founder of MicroSeismic, Inc. "This second award demonstrates the work we are doing in the Marcellus and other plays is creating value for our customers."

Gastar's Vice President and Exploration Manager, Keith Blair, commented, "Gastar has used MSI's FracStar in East Texas and because of the knowledge gained we have decided to implement their BuriedArray in our Marcellus Shale Play. We look forward to optimizing our completion techniques and in turn maximizing our production and minimizing our capital investment from the microseismic data gathered."

Clients currently using FracStar^® for one-off well monitoring in the Marcellus are realizing the value of surface microseismic results and are increasingly moving toward BuriedArray services, which offer long-term, field-wide, microseismic monitoring capabilities.

The BuriedArray data acquisition is ideal for operators who need to monitor multiple wells and need monitoring over a longer period of time. The ability to monitor large areas leads to more strategic field planning and development. The BuriedArray method drives down the cost of monitoring and provides the lowest per well monitoring cost in the industry.

About MicroSeismic, Inc.
MicroSeismic, Inc. (MSI) is a global geophysical service company providing real-time monitoring and mapping of hydraulic fracture operations for developing unconventional oil and gas plays. Founded in 2003, MSI is the pioneer in monitoring microseismic activity utilizing surface and near-surface arrays. MSI's technology provides real-time information on fracture location and geometry helping operators increase production and recovery while decreasing cost and risk. For more information, visit www.microseismic.com.

About Gastar Exploration Ltd.
Gastar Exploration Ltd. is an independent company engaged in the exploration, development and production of natural gas and oil in the United States. Our principal business activities include the identification, acquisition, and subsequent exploration and development of natural gas and oil properties with an emphasis on prospective deep structures identified through seismic and other analytical techniques as well as unconventional natural gas reserves, such as shale resource plays. We are pursuing natural gas exploration in the deep Bossier gas play in the Hilltop area in East Texas and the Marcellus Shale in West Virginia and central and southwestern Pennsylvania. We also conduct coal bed methane development activities within the Powder River Basin of Wyoming and Montana. For more information, visit our web site at www.gastar.com.