Seismic Survey Shaking Up Long Beach
- By Allison Jean Eaton
- | Saturday, 05 March 2011 17:18
A Long Beach police officer leads a train of four vibroseis trucks as they inch forward before sending another round of acoustical energy into the ground on Anaheim Street just west of Obispo Avenue last Friday as part of the Long Beach-Signal Hill Geographical Survey.
10:46am | Oversized trucks traveling in a group of four continued to shake the streets of Long Beach last week as part of the Long Beach-Signal Hill Geophysical Survey.
Last Tuesday, the vibroseis survey trucks, escorted by two black-and-whites from the Long Beach Police Department, slowly made their way up the middle of Redondo Avenue, stopping every few yards and lowering their seismic vibrators to the pavement below to input acoustical energy into the ground. The trucks were spotted by the Long Beach Post again last Friday, traveling west on Anaheim Street.
Drivers might not have felt the resultant vibrations, but anyone walking along the sidewalks adjacent to the trucks would have been hard pressed to not notice the ground shaking.
The survey, which launched on Jan. 18, is slated to continue through the first half of 2011, according to an informational brochure provided by a survey technician as he monitored the sidewalk alongside the quartet of earth-shaking vehicles.
While the survey is being sponsored by Signal Hill Petroleum Inc. to identify any additional oil resources that might exist, it will also provide a current map of the geophysical strata beneath the two cities, as well as identify any significant subsurface conditions such as potential faults, according to the survey brochure.
This is all accomplished through seismic imaging. The acoustic waves the trucks send into the ground penetrate deep into the earth. As they pass by the various geographical strata, acoustic reflections are created. These reflections are recorded by small, specialized recording devices called nodes that have been previously inserted into the ground in strategic locations. The data recorded by the nodes is then downloaded and processed by state-of-the-art computer programs that generate three-dimensional images of the earth's subsurface and deeper geology.
The seismic imaging process does not damage the street or negatively impact the earth below ground.
The survey team, which is headed up by NodalSeismic LLC, is working in conjunction with several universities and government agencies with which it will share the data for academic and scientific research, according to the survey brochure.
A website, LBGeophysical.com, has been created specifically for the survey and provides detailed information about the effort, including a community calendar identifying where the trucks will be operating on a particular date. The survey is conducted on weekdays between 9 a.m. and 4 p.m.
This week, the trucks will continue heading west on Anaheim from Temple Avenue to Martin Luther King Boulevard on Monday. They will head south on Cherry Avenue from 19th Street to Anaheim on Tuesday, and on Wednesday, they will head west on Seventh Street from Walnut Avenue to Atlantic Avenue and from Federation Drive to Obispo Avenue. Thursday will find them heading west on Seventh from Obispo to Walnut as well as west on Anaheim from Martin Luther King to Atlantic. Finally, they will head south on Orange Avenue from Hill Street to 17th Street and south on Alamitos Avenue from 17th to Seventh on Friday.
While most of the survey is being conducted on public streets, select off-street commercial locations and vacant lots may also be surveyed if permission is granted by the land owner.
Anyone with questions or concerns is asked to contact the project manager by calling 562-326-5186. Additionally, any related emergencies should be reported to Signal Hill Petroleum by calling 562-595-6440.
A survey technician records a seismic reading onto a clipboard as four vibroseis trucks input acoustical energy into the ground on Anaheim Street just west of Obispo Avenue last Friday as part of the Long Beach-Signal Hill Geographical Survey.
A Long Beach police officer trails behind four vibroseis trucks as they inch forward before sending another round of acoustical energy into the earth on Anaheim Street just west of Obispo Avenue last Friday as part of the Long Beach-Signal Hill Geographical Survey.