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Surface Wave Investigation and Analysis Earthquake-Induced Liquefaction Sites in Asia

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Example SASW Data Set


Wadamisaki District, West Kobe City, Japan


Field Testing

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Land sat photo of Kobe, Japan. SASW sites along a railroad right-of way.
The Kobe SASW sites span the city. Wadamisaki is in the western district. (68K) Our SASW sites are situated along a railway right-of-way. Part of the railway line had surface evidence for liquefaction, and about half had none. (64K)
Photo of the Wadamisaki district in Kobe. Photo of SASW gear at the railway tracks.
Wadamisaki district is densely urbanized. The JR line was rare open space for testing. Many structures were damaged by shaking and liquefaction in 1995. (60K) For 7 hours each day, no trains service the Wadamisaki line. We had permission to test along a railway right-of-way during no-service times.(48K)
SASW gear rolling down the railroad tracks. Photo of SASW gear set up along the railroad tracks.
To get our SASW equipment onto the railroad-line right-of-way, JR WEST gave us our own little train. We pushed the gear into place to test. (48K) To get our SASW equipment onto the railroad-line right-of-way, JR WEST gave us our own little train. We pushed the gear into place to test. (60K)

Data Analysis

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Penetration logs for the Wadamisaki District. Grain size graph of critical layer.
The KOBE JIBANKUN GIS database was used to pull SPT penetration logs for the Wadamisaki District and determine the critical liquefaction soil layers. (56K) Part of the KOBE JIBANKUN GIS database includes grain size information that is important in liquefaction analysis. (e.g., mean & variance for fines%).(64K)
Inversion method on the JR Wadamisaki line, Sites 106-113. Calculated mean and variance Vs for the critical layers.
We compute shear wave velocities for all the SASW sites by the Haskell-Thompson inversion method. (80K) Critical layers from the liquefaction assessment of the KOBE JIBANKUN GIS database were used to calculate mean & variance for Vs. (64K)
2-D image of probabilistic parameters of the shear wave velocities. Cyclic stress Ratio-shear wave velocity plot.
Probabilistic parameters of the shear wave velocities for all the SASW sites are assessed in a GIS format tha allows spatial analysis of liquefaction layers. (80K) Liquefaction triggering analysis of each site is presented on a Cyclic Stress Ratio-Shear wave velocity plot. Here, red ellipses indicate liquefaction sites (mean = center point, and ±1 sigma values define ellipse. Blue colored ellipse are for none-liquefaction sites. (80K)


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For further information PLEASE CONTACT: Robert Kayen
last modified 1 December 2003 (lzt)
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