We want to thank all those concerned for your curiousity, patience and understanding throughout the project!
Vibration truck positions are estimates only and actual positions and routes may vary and are subject to change.
These routes are best “estimates”. As we are all aware, local traffic conditions are always subject to change,
which makes the daily routes a projection, but also, it is impossible to determine exactly when we will be going on any particular street.
Thank you for your understanding.
Please review the information on this page and if you still have questions,
we welcome calls to our Project Information Line at (562) 424-1145.
Maps will be updated every Friday for the upcoming week's survey truck routes.
Each Wednesday in advance of survey truck activity, brochures will be mailed out to those households within 300 feet of the routes.
Questions or concerns? Please call our Project Information Line at
Geologic mapping is a highly-interpretive, scientific process which produces a range of map products for many different uses. A key component in the construction of geologic maps is the acquisition of seismic data. Data created by this project will allow scientific studies on the behavior of geologic strata in the area. This data plays a vital role in creating a clear picture of the subsurface. The density of sensors (Nodes) will also allow us to look at the micro seismicity on how deformation is taking place on a small-scale and how it changes with time.
This particular project, ‘Seismic Survey 2017’ is being performed over a larger area than any previous subsurface geological surveys in the LA Basin. Also, tremendous advances in technology have occurred in the intervening five years since a 3D was performed over some of this same area. Those advances encompass the full range of Seismic Mapping Technology Design-allowing for a more sophisticated placement of the listening devices, and the Survey Trucks.
Breakthroughs have revolutionized the analysis of the data to make this map the clearest picture ever made in this very important area of the LA Basin.
Newer generation Nodes have improved the sensitivity and range of the area that the vibrations can be picked up and recorded coherently. The Survey Trucks now only require half the time and lower levels of vibration than in any prior surveys.
Imaging of subsurface strata is accomplished by using state of the art technology to input acoustical energy
into the ground by using specialized trucks and very sensitive passive wireless listening devices called Nodes.
Nodes record the reflections of sound bouncing off layers of rock strata. The recorded data is downloaded and processed by highly-sophisticated programs that generate a three-dimensional image of the earth's layers.
In most cases the Nodes are placed in the public right of way. On private property, Access Agreements are obtained from landowners. Small holes about 8 inches in diameter by 11 inches in depth are dug, in which the Nodes are buried to record data; in fact, they cannot be seen at all during operations. The Nodes are completely passive and emit no energy. They strictly record and store data. Upon project completion, the Nodes are removed, and any disturbed areas will be restored. Survey trucks will operate mostly on public streets. Where there are no streets available, we obtain permits to enter private property. The trucks create a minor surface vibration when they emit the acoustical energy into the ground. The energy levels are very similar to recycling trucks. Technicians monitor surface ground vibration levels with digital
recording meters at every location. Survey trucks will be at any one location between 3 and 5 minutes.