Site Characterization Using Seismic Velocity Testing and its Incorporation into a Relational Database

Jessica Ledesma, Tristan E. Buckreis, & Jonathan P. Stewart

Published September 11, 2022, SCEC Contribution #12326, 2022 SCEC Annual Meeting Poster #233

Velocity data for any given site is a critical component for the prediction of earthquake ground motions used in design and construction of buildings and other structures. However, measurements of velocity data are not widely available or easily accessible to the public within the US. The motivation for creating the online Shear-Wave Velocity Profile Database (VSPDB) (Ahdi et al., 2018) (vspdb.org) was to make collected contributions of velocity data publicly available. Doing so promotes research and allows practicing engineers to access data to improve their designs in areas of active seismicity. Over the long term, these efforts will help reduce losses and risks in an earthquake, allowing for effective site planning. In this project, we have added new information to the VSPDB. Various datasets from multiple institutions and sources within California(https://earthquake.usgs.gov/monitoring/nsmp/arrays/) and South Carolina (South Carolina Department of Transportation (SCDOT) GIS website), containing the minimum criteria of location metadata and velocity data, were obtained and incorporated as a new site in the VSPDB. Velocities within relatively shallow soil layers were added from different measurement methods such as downhole, suspension logging, sCPT and multichannel analysis of surface waves. Boring, Cone Penetrometer Test, and Standard Penetration Test information were also included if these data types were available. Any calculated values were not included as only measured data was added; an example of an excluded calculated variable would be Vs30. The information from each site was transferred into their own JavaScript Object Notation file through UNIFY and used to assign primary and foreign keys within the relational database schema during upload to the VSPDB. On the backend, queries are constructed using Structured Query Language and pushed onto the database. A total of an additional 11 sites were input to the VSPDB. For each added site, the original source of the published data is provided within the VSPDB. The first author attained knowledgeable research experience throughout the process of working on this project. She learned the importance of seismic velocity data, several methods for measuring velocity and its implications for earthquake engineers. She was also introduced to relational databases and discovered the benefits of using a relational database by gaining an understanding of how they are structured.

Key Words
Shear-Wave Velocity, Database, Site Characterization

Citation
Ledesma, J., Buckreis, T. E., & Stewart, J. P. (2022, 09). Site Characterization Using Seismic Velocity Testing and its Incorporation into a Relational Database. Poster Presentation at 2022 SCEC Annual Meeting.

Related Projects & Working Groups
Ground Motions