Year of selection 2017
Institution Earth Observatory of Singapore
Rapid urbanisation and population growth puts more and more people in earthquakes’ paths. In southwestern China, along the highly-active Xiaojiang fault, rapid economical growth is fuelling major infrastructure projects and population growth, exposing millions to conditions of elevated risk. Throughout human history, numerous destructive earthquakes have struck the region, of which four measured more than 7 on the Richter scale. The largest was the 1833 Songming earthquake of magnitude 8, which resulted in the death of thousands of people. Recognising the critical knowledge gap in the field of earthquake geology in this region, Dr. Xuhua Shi of the Earth Observatory of Singapore, aims to provide decision-makers with a detailed knowledge of the characteristics and seismic behaviour of the Xiaojiang fault to increase resilience in the future.
« The Xiaojiang fault is one of the fastest-moving faults in China », Dr. Xuhua Shi reports. « But we know very little about it. For instance, there is a debate on how often earthquakes happen in the region. Some put the average gap between two major earthquakes at about 2,000 years or more. Others put it at 300-500 years ». With now more than 10 million people living in the vicinity of the Xiaojiang fault, and the construction of massive infrastructure projects (hydropower dams, oil and gas pipelines), providing answers to such questions has become critical. « Previous studies have not been able to properly mapped the active fault traces. The necessary technology was not available at the time », Dr. Xuhua Shi explains. « Today, it is, and we have the means to obtain precise locations of the fault traces».
Exploring the past to prepare for the future
The first step of Dr. Xuhua Shi’s project is thus to use state-of-the-art technology to precisely map the 350 km-long fault, and to provide a high-resolution fault location map. « Then, I aim to use the maps and the high-resolution digital elevation models to determine spatial distribution of co-seismic slips of historic earthquakes along the fault », he specifies. « This will give us insight into the behaviour of the fault in case of an earthquake, whether it differs from one earthquake to another, or stays substantially the same ». Once the first step is completed, Dr. Xuhua Shi and his team will be able to identity key sites to conduct field studies. Using radiocarbon dating of sediments, the second objective will be to investigate the recurrence characteristics and rupture behaviours of large historic earthquakes.
Mitigating the impact of future earthquakes along the Xiaojiang fault has extremely high stakes. Its geographic position, in the mountainous area connecting China to Myanmar, Thailand, Lao and Vietnam, places it in a strategically important area for Chinese economical development. Furthermore, the combination of rugged terrain and dense populations urgently calls for a modern evaluation of seismic hazard. By providing decision-makers with a solid basis to assess seismic hazard in the southwestern region of China, Dr. Xuhua Shi’s project will fill a critical gap and contribute greatly to hazard resilience.