Park Seismic provides services in data processing and reporting in MASW surveys for various types of projects (wind-turbine, soil, void, bedrock, weak zones, buried boundaries, etc.). For cost-effective and time-efficient purposes, field surveys are usually performed by a local geophysical company with experience in zultichannel seismic surveys (refraction or reflection seismic surveys). Click for list of equipment necessary for MASW survey.

The overall procedure for the service usually consists of following steps:

1. Feasibility Inquiry

A client (usually a geophysical company) contacts Park Seismic to tap on the potential feasibility of using the MASW approach for a specific project by briefly describing the goal of the project such as stiffness evaluation of soil/bedrock or detection of specific subsurface features. Maximum surface distance and investigation depth range of the survey need to be specified and an approximate site geology (loose soil with bedrock depth less than 10 ft, etc.) and ground surface condition (pavement, excavated, grass, vegetated, etc.) may need to be specified as well. Site photos and/or borehole information if available will also help predict potential effectiveness of the survey and evaluate necessary field parameters for the survey. Park Seismic uses all this information to evaluate the feasibility based on theoretical and practical aspects of the MASW method. Computer-based simulation (modeling) is sometimes executed for a more accurate prediction. Click for a sample simulation. Park Seismic then provides feedback with a practical expectation for the survey results. Required survey equipment such as type of seismic source and receivers, and number of seismograph channels will also be identified.

2. Survey Plans and Cost Evaluation

If client chooses to proceed with the MASW survey after considering the feasibility evaluation provided by Park Seismic, survey plans and estimated cost (quotation) are provided to the client. Options usually provide variations in cost and overall integrity of the survey. A small-scale pilot survey is often recommended as an option before the full-blown survey takes place to make a preliminary evaluation of the suggested acquisition parameters or overall effectiveness of the MASW approach for the project. Contact Us for price information on typical surveys. Click for a sample quotation and sample acquisition plan.

3. Field Survey

Once survey plans are agreed upon and field crews and equipment are ready, the field survey takes place according to a time schedule set by both the client and Park Seismic. If a pilot survey has been chosen, the first day of surveying is dedicated for the pilot and data set acquired is sent to Park Seismic at the end of the day. Preliminary analysis of the pilot survey data takes place immediately and results are delivered back to the field crews by next morning along with recommendations of any possible adjustments to the field parameters. Click for a sample preliminary report. Once the actual production survey begins, acquired data set can be sent to Park Seismic at the end of each day so that the preliminary evaluation can be delivered back to the survey crews by next morning. This can be very useful in continuous monitoring of field operation for any necessity, to modify acquisition parameters due to unexpected changes in surface and subsurface conditions, and also for prompt interaction with other field activities.

4. Data Processing and Reporting

After all data sets are delivered to Park Seismic, detailed analysis takes place promptly and a draft report will be sent to the client via email. A data set of one field day usually takes 1-3 days until a draft report can be submitted, depending on the complexity of data and analysis options chosen. The final report is submitted within 1-2 weeks after this in the form of both electronic files on CD and printed documents. During this period, minor changes or adjustments are made if necessary for certain parts of the analysis or reporting format based on communication (via email or telephone) between client and Park Seismic. The final report usually includes data files of shear-wave velocity (Vs) values at different depths along the surveyed lines. The report can be either in a compact or a full format; see sample compact 1D MASW report, sample full 1D MASW report, sample compact 2D MASW report, and sample full 2D MASW report.