Title

A new electrical and mechanically detonatable shear wave source for near surface (0-30m) seismic acquisition

Document Type

Article

Publication Date

4-1-2013

Abstract

We present a new, impulsive, horizontal shear source capable of performing long shot profiles in a time-efficient and repeatable manner. The new shear source is ground-coupled by eight 1/2" (1.27. cm) × 2" (5.08. cm) steel spikes. Blank shotshells (12-gauge) used as energy sources can be either mechanically or electrically detonated. Electrical fuses have a start time repeatability of < 50. μs. This source can be operated by a single individual, and takes only ~. 10. s between shots as opposed to ~. 30. s for six stacked hammer blows. To ensure complete safety, the shotshell holder is surrounded by a protective 6" (15.24. cm)-thick barrel, a push-and-twist-locked breach, and a safety pin.We conducted field tests at the 17th Street Canal levee breach site in New Orleans, Louisiana (30.017° N 90.121° W) and at an instrumented test borehole at Millsaps College in Jackson, Mississippi (32.325° N 93.182° W) to compare our new source and a traditional hammer impact source. The new shear source produces a broader-band of frequencies (30-100. Hz cf. 30-60. Hz). Signal generated by the new shear source has signal-to-noise ratios equivalent to ~. 3 stacked hammer blows to the hammer impact source. Ideal source signals must be broadband in frequency, have a high SNR, be consistent, and have precise start times; all traits of the new shear source. © 2013 Elsevier B.V.

Publication Source (Journal or Book title)

Journal of Applied Geophysics

First Page

1

Last Page

8

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