New airborne remote sensing techniques and tools are helping scientists gain a better understanding of earthquakes. Airborne sensors provide the advantage of being able to cover a great deal of ground, and through repeated visits they give in-depth picture of change across an entire fault line. Remote sensing also provides a reliable means to augment the network of ground sensors to provide a different perspective.

A science team at NASAs Jet Propulsion Laboratory in California has been using the Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) to measure surface deformation from earthquakes. The radar produces map images that are called interferograms that show ground motion and increased strain along fault lines.

By comparing imagery collected over time, the scientists are able to better understand the complex geology of these regions. Through continued observation, particularly after a quake event, the scientists can determine how strain alters across a fault line, and can help determine if massing of strain along the fault is occurring, priming them to break. The UAVSAR sensor shows details at a much finer granularity than any other type of sensor.

Interesting research is taking place throughout the world to help determine a reliable precursor for earthquake detection:

• The China Institute for Remote Sensing Applications (IRSA) is studying the possibility of earthquake signal detection through the use of space and ground observation technology in the microwave spectrum. Dr. Yun Shao is the Director of the Microwave Research Division at IRSA, and has been exploring the use of multi-temporal Synthetic Aperture Radar (SAR) and microwave scatterometer (QSCAT and ASCAT) data to help predict the potential for earthquakes.
• Researchers in India have been studying the use of thermal remote sensing instruments to determine if heat transfer is a reliable earthquake precursor.
• A plan to study the electrical disturbance in the atmosphere that occurs prior to an earthquake is also underway. Surrey Satellite Technology Limited proposes a constellation of 20 satellites to monitor this warning signal from space, claiming that the electrical charge that occurs as pressure builds up for a quake can be detected weeks in advance.

Clearly, there are promising remote sensing technologies that will not only help us assess the damage from earthquake events, but also to predict and help mitigate their damage.