Lidar Provides Better Study of Active Fault Zone

An active seismic fault in China has been the scene of several deadly earthquakes — some of the worst in history. Digital 3-D modeling of the fault zone could help save lives, researchers say.

A team from the State Key Laboratory of Earthquake Dynamics and the National Earthquake Infrastructure Service in Beijing, in collaboration with the US Geological Survey, said they can now better recognize the link between fault activity and large earthquakes, “as well as the potential risk for future earthquake hazards.”

The team deployed a Leica ALS-60 lidar system mounted aboard a Chinese Yun Five aircraft to obtain extremely precise topographical measurements of the Haiyuan fault zone in western China. A key feature of the system was its virtual removal of vegetation from the topographical images, conveying a bare representation of the land that allowed for more accurate identification of tectonic features and changes following earthquakes and ruptures.

The collected data was used to generate a 3-D model employed to calculate co-seismic offsets, tectonic landform features and displacement measurements. The system could help predict future temblors, according to the researchers.

The new technique was also used to examine a part of Gansu province adjacent to the fault line; it identified 600 channels and other linear geomorphic features that will be more comprehensively analyzed.

Separately, the researchers also mapped an area in Sichuan province in southwestern China which was the epicenter of a massive 7.9 M_w earthquake in 2008, and used the resulting data to record the scale of landslides and develop rescue plans.

The next step is to “measure the displacements along the whole Haiyuan fault and analyze the principle of the slip distribution,” according to the researchers.

The new technique has achieved higher data resolution than existing methods, helping the researchers to map fault trace locations more accurately than in the past. The researchers expect that the survey system will ultimately pave the way for development of other similar models.

The research was published in the Chinese Science Bulletin (doi: 10.1007/s11434-014-0199-4).

For more information, visit www.eq-igl.ac.cn.