The Equation of Motion of a Geophone on the Surface of an Elastic Earth

Wolf, Alfred A.

doi:10.1190/1.1445065

“…Receiver coupling to the seafloor was investigated by civil engineers and geophysicists since the 1930s and is based on a model of soil interaction with a receiver system (e.g. Reissner ; Wolf ; Hsieh ; Robertson ; Lysmer and Richart ; Lamer ; Luco and Westmann ; Luco , ; Bycroft ; Safar ; Hoover and O'Brien ; Dorn ).…”

Section: Theorymentioning

confidence: 99%

Seismic receiver coupling to the seafloor

Landschulze¹

2019

Geophysical Prospecting

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The presence of geophysical receivers on the seafloor changes the local wave field due to the receiver seafloor interaction. The resulting PP‐ and PS‐wave distortion of the wave field is often referred to as receiver coupling to the seafloor and can make data processing challenging and sometimes impossible. This paper provides an overview of the mathematical approaches to describe receiver coupling, how to estimate receiver coupling and what the difficulties and possible solutions are. The first section shows how the mathematical approach developed from a simple model considering only the vertical receiver component to include all three receiver components and their interactions with the seafloor. In the second section, I show how receiver coupling can be measured and how it can be improved using mathematical and data‐driven approaches.

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“…Although experimental and theoretical results have been obtained using massive geophones (Wolf, 1944;Hoover and O 'Brien, 1980), the effect of a large range of masses on geophone oscillation has not been fully explored. Steeples et al (1999) reintroduced the massive geophone issue while discussing possible automatic geophone-planting devices.…”

Section: Introductionmentioning

confidence: 99%

Varying the effective mass of geophones

Spikes

¹

,

Steeples

²

,

Schmeissner

³

et al. 2001

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Traditionally, acquiring seismic data has rested on the assumption that geophone mass should be as small as possible. When Steeples and coworkers in 1999 planted 72 geophones automatically and simultaneously with a farm tillage implement, the effective mass of each of the geophones was significantly increased. We examined how the mass of a geophone affects changes in traveltime, amplitude, frequency, and overall data quality by placing various external masses on top of 100-Hz vertical geophones. Circular barbell weights of 1.1-, 11.3-, and 22.7 kg; an 8.2-kg bag of lead shot; and a 136-kg stack of barbell weights were placed on top of geophones during data acquisition. In addition, a very large mass in the form of a truck was parked on top of two of the geophones. Four seismic sources supplying a broad range of energies were tested: a sledgehammer, a .22-caliber rifle, a 30.06 rifle, and an 8-gauge Betsy Seisgun. Spectral analysis revealed that the smaller weights had the greatest effects on the capacities of the geophones to replicate the earth's motion. Consequently, using geophones with a large effective mass as part of an automatic geophoneplanting device would not necessarily be detrimental to the collection of high-quality near-surface seismic data.

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“…Therefore, the purpose of the experiments discussed here was to test how geophone mass affected the traveltime, amplitude, and frequency of shallow subsurface seismic data. Previous work on this subject includes that of Wolf (1944), who showed theoretically that a geophone resting on an elastic surface reacted to incident elastic waves like a simple, damped harmonic oscillator. He assumed that the geophone was a right cylinder with a mass of approximately 11.3 kg and that the circular base plate was in perfect contact with the ground.…”

Section: Introductionmentioning

confidence: 99%

“…An absolute minimum mass, theoretically zero, was needed to duplicate broadband ground motion. He determined that the ground motion due to frequencies above the natural frequency of the oscillating system would not be faithfully reproduced but that geophones could replicate the ground motions associated with lower frequencies (Wolf, 1944). Hoover and O'Brien (1980) experimented with geophones equipped with circular base plates.…”

Section: Introductionmentioning

confidence: 99%

Varying the effective mass of geophones

Spikes¹,

Steeples²,

Schmeissner³

et al. 2000

SEG Technical Program Expanded Abstracts 2000

View full text Add to dashboard Cite

Traditionally, acquiring seismic data has rested on the assumption that geophone mass should be as small as possible. When Steeples and coworkers in 1999 planted 72 geophones automatically and simultaneously with a farm tillage implement, the effective mass of each of the geophones was significantly increased. We examined how the mass of a geophone affects changes in traveltime, amplitude, frequency, and overall data quality by placing various external masses on top of 100-Hz vertical geophones. Circular barbell weights of 1.1-, 11.3-, and 22.7 kg; an 8.2-kg bag of lead shot; and a 136-kg stack of barbell weights were placed on top of geophones during data acquisition. In addition, a very large mass in the form of a truck was parked on top of two of the geophones. Four seismic sources supplying a broad range of energies were tested: a sledgehammer, a .22-caliber rifle, a 30.06 rifle, and an 8-gauge Betsy Seisgun. Spectral analysis revealed that the smaller weights had the greatest effects on the capacities of the geophones to replicate the earth's motion. Consequently, using geophones with a large effective mass as part of an automatic geophoneplanting device would not necessarily be detrimental to the collection of high-quality near-surface seismic data.

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The Equation of Motion of a Geophone on the Surface of an Elastic Earth

Cited by 34 publications

References 0 publications

Seismic receiver coupling to the seafloor

Seismic receiver coupling to the seafloor

Varying the effective mass of geophones

Varying the effective mass of geophones

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