Slip rate along the Lijiang-Ninglang fault zone estimated from repeating microearthquakes

December 22, 2008

The China Digital Seismic Network (CDSN) provides excellent opportunities to quantify the kinematics and characterize the dynamics of the active fault systems in China. By carefully examining waveforms microearthquakes occurring in South China (Yunnan Province) in the period of 1999--2006, we found that approximately 40% of the earthquakes are similar or repeating events. Along the Lijiang-Ninglang fault, we used 2 well-organized clusters that occurred in the brittle-ductile transition zone to estimate the deep slip rate. The estimated slip rate of 5 mm/yr at 23 km depth roughly agrees with the tectonic loading rate inferred from geologic and geodetic data. The discovery of repeating microearthquakes in China (see Li et al., 2007) provides a new means for inferring the slip rate at depth along active faults, the nests of large devastating earthquakes.

The study was mainly conducted by Dr. CHEN Qifu and Dr. LI Le from the Institute of Earthquake Science, China Earthquake Administration in collaboration with Dr. NIU Fenglin from Rice University, and has been published in Volume 53 Issue 23 (December 15, 2008) of Chinese Science Bulletin in Chinese, and published online on November 4, 2008 in English.

Fault slip rate is a key parameter to infer the recurrence of earthquakes. It has been widely investigated with mainly geologic and geodetic methods. Most of the geologic and geodetic observations are, however, surficial measurements, which are frequently not even close to those occurring at seismogenic depth, as demonstrated by the devastating Wenchuan earthquake occurring at the east edge of the Tibetan Plateau in May, 2008. According to most of the geodetic observations, little deformation was identified across the Longmenshan fault that hosted the earthquake. As such, in-situ measurement of slip rates at seismogenic depths from the recurrence of repeating microearthquakes could be crucial. Meanwhile studying the spatial distribution of these repeating microearthquakes could provide another perspective of earthquakes, the size of the large asperities that may directly link to the future large earthquakes.
This study is supported by National Basic Research Program of China (Grant No. 2004CB418405) and National Natural Science Foundation of China (Grant No. 40174014).

Reference: Li Le, Chen Qifu, Niu Fenglin, Fu Hong, Liu Ruifeng, Hou Yanyan, , Slip rate in the Lijiang-Ninglang fault zone estimated from repeatingmicroearthquakes. Chin Sci Bull, 2008, 53, doi: 10.1007/s11434-008-0406-2, published on online November 4, 2008

Li Le, Chen QiFu, Cheng Xin, Niu Fenglin, Spatial clustering and repeating of seismic events observed along the 1976 Tangshan fault, North China, Geophys Res Lett, 2007, 34(23),L23309, doi: 10.1029/2007GL031594

Science China Press

Related Earthquake Articles from Brightsurf:

Healthcare's earthquake: Lessons from COVID-19
Leaders and clinician researchers from Beth Israel Lahey Health propose using complexity science to identify strategies that healthcare organizations can use to respond better to the ongoing pandemic and to anticipate future challenges to healthcare delivery.

Earthquake lightning: Mysterious luminescence phenomena
Photoemission induced by rock fracturing can occur as a result of landslides associated with earthquakes.

How earthquake swarms arise
A new fault simulator maps out how interactions between pressure, friction and fluids rising through a fault zone can lead to slow-motion quakes and seismic swarms.

Typhoon changed earthquake patterns
Intensive erosion can temporarily change the earthquake activity (seismicity) of a region significantly.

Cause of abnormal groundwater rise after large earthquake
Abnormal rises in groundwater levels after large earthquakes has been observed all over the world, but the cause has remained unknown due to a lack of comparative data before & after earthquakes.

New clues to deep earthquake mystery
A new understanding of our planet's deepest earthquakes could help unravel one of the most mysterious geophysical processes on Earth.

Fracking and earthquake risk
Earthquakes caused by hydraulic fracturing can damage property and endanger lives.

Earthquake symmetry
A recent study investigated around 100,000 localized seismic events to search for patterns in the data.

Crowdsourcing speeds up earthquake monitoring
Data produced by Internet users can help to speed up the detection of earthquakes.

Geophysics: A surprising, cascading earthquake
The Kaikoura earthquake in New Zealand in 2016 caused widespread damage.

Read More: Earthquake News and Earthquake Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to