C-2: Settlement of Extensometers and Seismographs in
the Lishan Landslide, Xian, China
Top left and right: Extensometer settled on the
Lishan slope, Bottom left: Amplifier and digital
data recorder for seismometers, Bottom right: 3-
comp. seismometer settled inside the
investigation tunnel in the Lishan slope.
Huaqin Pool is an ancient palace of Tang dynasty in China, and one of the most famous tourist resorts in China now where more than three million tourists are visiting every year. The northern slope of Mt. Lishan, located behind this pool, has been showing slope deformation at many places in recent years. Various investigation and monitoring had been carried out and their results imply the possibility that the slope is a potential landslide. Since 1991 joint research by Disaster Prevention Research Institute(DPRI), Kyoto University and Xian Municipal Government started.
DPRI brought the three dimensional shear displacement meters, borehole inclinometer, total station with mirror targets, and GPS receivers for satellite survey to the Lishan landslide and precise movement monitoring was begun. Until today, the Lishan Landslide Observatory was established by the Xian municipal government and twenty staffs are engaged in landslide observation.
In 1996 settling of extensometers and seismographs is planned. In March and May three researchers of DPRl and Kochi University visited Lishan landslide and settled 12 extensometers along two investigation lines as well as 2 sets of 3-comp. seismometers inside the investigation tunnel on the Lishan slope.
As for extensometers settlement, concrete poles of more than 10 meters long are mounted on the Lishan slope with pulleys on their top and super-invar wires are passed between them. Extensometers are installed in metal boxes bundled at their foot( Top left & right photos). Total length of the extensometer investigation line is about 700 meters.
Expected precision of extensometer observation is 0.1mm. As for seismographs( Botom left & right photos), two velocity-type 3-comp. seismometers are settled on basal Precambrian rock at the end of the 40-meters-long investigation tunnel and also on a weathered rock layer above it. Seismic observation is mainly focused on the characteristics of seismic wave motion and seismic effects upon the potential landslide.
In this October, 6 to 8 persons will visit Lishan landslide and field investigation, observation, and tuning of monitoring instruments will be undertaken. In July 1997, the International Symposium on Landslide Hazard Assessment will be organized at the Lishan landslide.
This meeting will be organized jointly, by the Japanese Ministry of Education, Science, Sports and Culture, the Working Group for Prediction of Rapid Landslide Motion( WG/RLM ), the International Union of Forestry Research Organization( IUFRO ), as well as DPRl and Xian Municipal Government. Results and achievement of this joint research program will be reported and discussed in the symposium.
