Imaging the earth with passive seismic arrays

2003 ◽  
Vol 22 (3) ◽  
pp. 224-231 ◽  
Author(s):  
Gary L. Pavlis
Keyword(s):  
Seismic Arrays ◽  
The Earth ◽  
Passive Seismic

Passive seismic velocity monitoring of natural faults: The FaultScan project

2020 ◽  
Author(s):  
Florent Brenguier ◽  
Aurelien Mordret ◽  
Yehuda Ben-Zion ◽  
Frank Vernon ◽  
Pierre Boué ◽  
...  
Keyword(s):  
Seismic Velocity ◽  
Fault Zones ◽  
Body Waves ◽  
Fault System ◽  
Seismic Arrays ◽  
San Jacinto Fault ◽  
Highway Network ◽  
Seismic Velocity Changes ◽  
Passive Seismic ◽  
Velocity Changes

<p>Laboratory experiments report that detectable seismic velocity changes should occur in the vicinity of fault zones prior to earthquakes. However, operating permanent active seismic sources to monitor natural faults at seismogenic depth has been nearly impossible to achieve. The FaultScan project (Univ. Grenoble Alpes, Univ. Cal. San Diego, Univ. South. Cal.) aims at leveraging permanent cultural sources of ambient seismic noise to continuously probe fault zones at a few kilometers depth with seismic interferometry. Results of an exploratory seismic experiment in Southern California demonstrate that correlations of train-generated seismic signals allow daily reconstruction of direct P body-waves probing the San Jacinto Fault down to 4 km depth. In order to study long-term earthquake preparation processes we will monitor the San Jacinto Fault using such approach for at least two years by deploying dense seismic arrays in the San Jacinto Fault region. The outcome of this project may facilitate monitoring the entire San Andreas Fault system using the railway and highway network of California. We acknowledge support from the European Research Council under grant No.~817803, FAULTSCAN.</p>

On bias and noise in passive seismic data from finite circular array data processed using SPAC methods

Geophysics ◽  
2006 ◽  
Vol 71 (6) ◽  
pp. V153-V162 ◽  
Author(s):  
Michael W. Asten
Keyword(s):  
Seismic Data ◽  
Seismic Noise ◽  
Imaginary Component ◽  
Empirical Measure ◽  
Restricted Range ◽  
Circular Array ◽  
Spatial Averaging ◽  
Seismic Arrays ◽  
Spectral Estimates ◽  
Passive Seismic

The finite nature of typical small seismic arrays used in conjunction with spatial autocorrelation (SPAC) processing for observing the microtremor wavefield causes predictable perturbations of the SPAC spectrum when sources of seismic noise are confined to a restricted range of azimuths. Such perturbations are especially evident at higher frequencies where wavelengths are on the order of the array radius. The effects are readily modeled and show that the triangular array geometries commonly used for microtremor studies require azimuthal distributions of wave energy on the order of [Formula: see text] or greater to have a high probability of being free of such perturbations. The imaginary component of the SPAC spectrum, which is ideally zero for a sufficiently dense circular array and/or a sufficiently isotropic wavefield, is in practice often nonzero and provides three quality-control indicators: (1) an indication of insufficient spatial averaging, (2) an empirical measure of the level of statistical uncertainty in SPAC spectral estimates, and (3) an indication of departures from plane-wave stationarity of the seismic noise wavefield.

scholarly journals SEISMIC AND ACOUSTIC MONITORING IN VOROTILOVSKAYA DEEP WELL: TECHNIQUE AND RESULTS

2017 ◽  
Author(s):  
А.С. Беляков ◽  
И.Н. Диденкулов ◽  
А.Д. Жигалин ◽  
В.С. Лавров ◽  
А.И. Малеханов ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Acoustic Noise ◽  
Acoustic Monitoring ◽  
Energetic Particles ◽  
Frequency Range ◽  
Deep Well ◽  
The Earth ◽  
Passive Seismic ◽  
Geodynamic Processes ◽  
Nizhny Novgorod Region

Наблюдения вариаций сейсмоакустического шума Земли показали эффективность пассивного сейсмического мониторинга при изучении эндогенных геодинамических процессов и связи их с интенсивностью сейсмоакустической эмиссии. В Воротиловской глубокой скважине (Нижегородская обл., Россия) регистрируется «шум Земли» в диапазоне частот от 1 Гц до 5 кГц. Шумы такого рода обычно связываются с особенностями тектоники и петрофизическими свойствами горных пород. В середине августа 2016 г. были зарегистрированы неординарные сейсмоакустические сигналы, которые предположительно связываются с взаимодействием высокоэнергичных частиц, в частности, нейтрино, с горными породами или возможным влиянием неопознанных источников, в том числе техногенных. Observations of variations in seismic and acoustic noise of the Earth has shown the effec-tiveness of passive seismic monitoring in the study of endogenous geodynamic processes and their connection with the intensity of acoustic emission. In Vorotilovskaya deep well (Nizhny Novgorod region, Russia) recorded the «earth noise» in the frequency range from 1 Hz to 5 kHz. The noise of this kind is usually associated with the features of tectonics and petrophysical prop-erties of rocks. In mid-August, 2017 extraordinary seismoacoustical signals were registered that are presumably associated with the interaction of highly energetic particles, in particular, neutri-nos with the rocks or the possible influence of unidentified sources, including technogenic.

Passive Seismic Monitoring Study of the Earth Degassing in the Arctic

2020 ◽  
Author(s):  
V. Bogoyavlensky ◽  
R. Nikonov ◽  
G. Erokhin ◽  
V. Bryskin
Keyword(s):  
Seismic Monitoring ◽  
The Arctic ◽  
The Earth ◽  
Monitoring Study ◽  
Passive Seismic

Correlation function of teleseismic noise

1968 ◽  
Vol 58 (2) ◽  
pp. 521-538
Author(s):  
K. R. Johnson
Keyword(s):  
Correlation Function ◽  
Seismic Waves ◽  
Vertical Component ◽  
Noise Spectrum ◽  
Spherically Symmetric ◽  
Seismic Arrays ◽  
The Earth ◽  
Diffraction Effects ◽  
Surface Diffraction ◽  
Surface Noise

Abstract A theoretical calculation is made of the correlation function for the vertical component of Earth motion caused by teleseismic microseismic noise. The calculation pertains to an idealized case in which the Earth is assumed to be spherically symmetric and to transmit seismic waves as a non-dispersive linear system, and in which all noise is assumed to originate at the Earth's surface. Diffraction effects are neglected. Only phases that originate and terminate as longitudinal waves are considered, although the method of analysis is readily applicable to other phases. The correlation function for teleseismic noise is calculated and plotted for the case of isotropic noise having a specific noise spectrum. The theoretical noise reduction is calculated and plotted versus average seismometer spacing for a set of seven-seismometer seismic arrays for the cases of teleseismic noise alone, surface noise alone, and a combination of teleseismic and surface noise.

scholarly journals Application of multichannel Wiener filters to the suppression of ambient seismic noise in passive seismic arrays

2008 ◽  
Vol 27 (2) ◽  
pp. 232-238 ◽  
Author(s):  
J. Wang ◽  
F. Tilmann ◽  
R. S. White ◽  
H. Soosalu ◽  
P. Bordoni
Keyword(s):  
Seismic Noise ◽  
Ambient Seismic Noise ◽  
Seismic Arrays ◽  
Wiener Filters ◽  
Passive Seismic

The Potential Role of Passive Seismic Monitoring for Real-Time 4D Reservoir Characterization

2005 ◽  
Vol 8 (01) ◽  
pp. 70-76 ◽  
Author(s):  
S.C. Maxwell ◽  
T.I. Urbancic
Keyword(s):  
Real Time ◽  
Petroleum Industry ◽  
Time Lapse ◽  
Seismic Monitoring ◽  
Oil Fields ◽  
Passive Monitoring ◽  
Seismic Arrays ◽  
Stress Changes ◽  
Passive Seismic ◽  
Potential Applications

Summary This paper details the application of passive seismic monitoring to image reservoir fracturing and deformation from the stage of an initial wellcompletion to final field production. Instrumented oil fields with seismic arrays either permanently installed or temporarily deployed on wireline offer the possibility of imaging production activities in a real-time sense that complements other seismic-reflection and engineering measurements. During the well-completion stage of development, real-time microseismic imaging offers the possibility of monitoring well stimulation. Fracture images may be used to optimize the fracture design and the net present value (NPV) of well production, as well as understand fracture complexity and the associated well-drainage pattern to target future well placement. During production stages, time-lapse microseismic imaging may be used for image deformation associated with fracturing or fracture reactivation from pressure or stress changes, strains in the overburden in fields with casing-deformation problems, and image fronts associated with secondary recovery. In this paper, several case studies are used to illustrate various potential applications, along with discussion of the potential limitations. The reservoir conditions necessary for the successful application of the technology are presented along with a potential method to quantify the technical feasibility at a particular site. Introduction With the current industry trend toward instrumented oil fields and smart-well completions, the permanent deployment of geophones or other acoustic sensors to complement standard engineering gauges is being promoted as a way to map reservoir dynamics. The biggest push is from active time-lapse seismic, although the deployment of permanent seismic instrumentation is also potentially an ideal route to monitor passive seismicity. Passive monitoring of acoustic emissions, or small-magnitude microearthquakes (microseismicity)associated with stress changes in and around the reservoir, can also be used to image the reservoir dynamics. Passive monitoring has the benefit of more fully using the seismic sensors to monitor during periods between conventional seismic surveys, directly imaging fracturing and deformation, and offers complementary information to both active time-lapse images and engineering measurements. Microseismic events, related to either induced movements on pre-existing structures or the creation of new fractures, capture deformations as the rock mass reacts to stresses and strains associated with pressure changes in the reservoir. The microseismicity can be used to localize the fracturing or to deduce geomechanical details of the deformation. Since the Rangely experiment in the late 1960s,1 a number of passive seismic experiments have been pursued in the petroleum industry with varying degrees of success.2–5 Recently, an umber of independent operators have successfully implemented passive seismic studies to address specific issues. The majority of these studies are under the umbrella of hydraulic fracturing,2,3 where the microseismicity is used to map the fracture growth directly during well stimulations. However, a number of other studies have been used to image deformations associated with primary production,4 secondary recovery,4 or waste-injection operations.5 In the vast majority of these cases, an array of seismic sensors is deployed by wireline to monitor for a specific period. This requires finding a well "close to the action" to facilitate detection of these small passive signals without impacting production. Permanent sensor deployment in an instrumented oil field circumvents the chronic problem of well availability. In numerous fields, microseismicity is continually occurring, and if the instrumentation were in place to record the data properly, additional information on the reservoir performance could be gained. As an aside, it is worth considering how much of the "noise" recorded in conventional seismics may be actually valuable microseismic data. The key will be to design the seismic arrays properly to cover both conventional active seismics (e.g., reflection and tomography) and specific issues associated with passive recording. This paper will outline a viewpoint of the potential applications and technical issues associated with passive seismic monitoring. Because passive seismics is probably best viewed as being in its infancy in the petroleum industry, it is worth standing back and considering applications in other industries in which the technology is more mature. In mining, real-time micro seismic data are used by supervisors to decide if it is safe to send miners underground.6 Microseismic data are also crucial in a number of other rock-engineering applications, such as excavation stability in nuclear-wasterepositories,7 geotechnical stability,8 and performance of geothermal reservoirs.9 Permanent instrumentation in oil fields also should allow the maturity of the technology to help solve certain geomechanical problems in the petroleum industry. This article generally will focus on borehole deployments because passive monitoring will most likely involve borehole arrays to keep the instrumentation close to the action and maximize sensitivity. In some special cases, where induced seismic activity can be detected at surface, permanent surface arrays could be used in a context similar to the picture painted in this paper. However, for the most part, the following discussion will focus on borehole arrays.

A Venus seismic experiment for the late 1970's

1971 ◽  
Vol 61 (6) ◽  
pp. 1731-1737
Author(s):  
John S. Derr
Keyword(s):  
Tectonic Activity ◽  
Seismic Velocities ◽  
Science Data ◽  
Science And Engineering ◽  
Active Experiment ◽  
The Earth ◽  
Seismic Experiment ◽  
Short Period ◽  
Passive Seismic ◽  
Passive Experiment

abstract NASA is planning a series of small-payload Venus missions, with launches beginning in 1976, some of which may be suited to small active and passive seismic experiments. Because the Earth and Venus are nearly the same size, one may theorize many parallels in seismic and tectonic activity, and any differences will provide information about the development of the Earth, as well as of Venus. A combined passive and active experiment with two separated short-period, three-component seismometers and one explosive charge may be carried as 3 entry vehicles on one spacecraft. The weight of explosive, however, is limited to about 20 kg. This limits the charge-seismometer separation to 1 or 2 km. Acoustic and radio ranging devices measure the positions of the 3 probes on the surface. Seismic velocities would be obtained for any layering down to about 500-m depth. A velocity transducer peaked at 20 Hz is desired for the active experiment, and would give some indication of the presence of microquakes on Venus, although a 1-sec period would be better for a passive experiment. An average science data rate of 30 bps would be adequate if the record from the active experiment is recorded for slower playback. A lifetime of 24 hr appears feasible. A dual launch of identical payloads landed in widely-separated areas would give a vastly greater return for the passive experiment. Although not unambiguous, the data should provide some information on seismic velocities, density, and anelasticity. Science and engineering data returned would determine desirability and feasibility of subsequent long-lived passive experiments with long-period, high-temperature instruments.

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