An automatic seismic event processing for detection and location: The P.M.C.C. Method

Cansi, Yves

doi:10.1029/95gl00468

Cited by 353 publications

(243 citation statements)

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“…Gradual evolution of observed waveforms implies a change either in the Greens function describing all propagation from source to receiver, or in the source time function. For seismic data, a change in waveform correlation over time typically implies a change in the source [Cansi, 1995] detection of infrasound from LPs was observed to switch on and off while the seismic LP events were continuously observed (see Figure S3). We also analyzed data from 1 to 19 March 2005 using the same method and obtained similar results.…”

Section: Waveform Cross Correlationmentioning

confidence: 99%

The source of infrasound associated with long‐period events at Mount St. Helens

Matoza¹,

Garcés²,

Chouet³

et al. 2009

J. Geophys. Res.

101

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[1] During the early stages of the [2004][2005][2006][2007][2008] Mount St. Helens eruption, the source process that produced a sustained sequence of repetitive long-period (LP) seismic events also produced impulsive broadband infrasonic signals in the atmosphere. To assess whether the signals could be generated simply by seismic-acoustic coupling from the shallow LP events, we perform finite difference simulation of the seismo-acoustic wavefield using a single numerical scheme for the elastic ground and atmosphere. The effects of topography, velocity structure, wind, and source configuration are considered. The simulations show that a shallow source buried in a homogeneous elastic solid produces a complex wave train in the atmosphere consisting of P/SV and Rayleigh wave energy converted locally along the propagation path, and acoustic energy originating from the source epicenter. Although the horizontal acoustic velocity of the latter is consistent with our data, the modeled amplitude ratios of pressure to vertical seismic velocity are too low in comparison with observations, and the characteristic differences in seismic and acoustic waveforms and spectra cannot be reproduced from a common point source. The observations therefore require a more complex source process in which the infrasonic signals are a record of only the broadband pressure excitation mechanism of the seismic LP events. The observations and numerical results can be explained by a model involving the repeated rapid pressure loss from a hydrothermal crack by venting into a shallow layer of loosely consolidated, highly permeable material. Heating by magmatic activity causes pressure to rise, periodically reaching the pressure threshold for rupture of the ''valve'' sealing the crack. Sudden opening of the valve generates the broadband infrasonic signal and simultaneously triggers the collapse of the crack, initiating resonance of the remaining fluid. Subtle waveform and amplitude variability of the infrasonic signals as recorded at an array 13.4 km to the NW of the volcano are attributed primarily to atmospheric boundary layer propagation effects, superimposed upon amplitude changes at the source.Citation: Matoza, R.

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Section: Waveform Cross Correlationmentioning

confidence: 99%

The source of infrasound associated with long‐period events at Mount St. Helens

Matoza¹,

Garcés²,

Chouet³

et al. 2009

J. Geophys. Res.

101

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“…The wave parameters of the hydroacoustic waves are calculated with the Progressive Multi-Channel Correlation method (PMCC). This method, originally designed for seismic arrays, proved to be very efficient for hydroacoustic data [Cansi, 1995;Graeber and Piserchia, 2004]. Thirty minutes after the main shock, PMCC algorithm begins to detect hydroacoustic waves propagating from the hypocenter (Figure 2).…”

Section: Hydroacoustic Array Of H08smentioning

confidence: 99%

Use of hydroacoustic and seismic arrays to observe rupture propagation and source extent of the M_w = 9.0 Sumatra earthquake

Guilbert

Vergoz

Schisselé

et al. 2005

Geophysical Research Letters

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[1] The rupture of the Sumatra earthquake (M w = 9.0) is complex and quite difficult to estimate using classical source inversion methods due to the exceptional rupture duration. To fix the problem of geographical extent and rupture duration, we use array processing of hydroacoustic and regional seismic data. The CMAR-seismic array and the Diego Garcia hydroacoustic station (H08S) installed by the International Monitoring System are respectively 15.2°and 25.7°far from the hypocenter. The estimation of azimuth and velocity variations of homogeneous wave fronts across the arrays gives us the opportunity to understand how the rupture propagates. The smooth and regular variations of azimuth fit a rupture extension of 1235 km and a duration of 515 s. This study proves that the combination of array analysis using the different technologies installed for the CTBT is an interesting way of research for a rapid estimation of tsunamigenic earthquakes. Citation: Guilbert, J., J. Vergoz, E. Schisselé, A. Roueff, and Y. Cansi (2005), Use of hydroacoustic and seismic arrays to observe rupture propagation and source extent of the M w = 9.0 Sumatra earthquake, Geophys. Res. Lett., 32, L15310,

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“…The array processing of the ETN data consists of a delay and sum analysis-based algorithm to detect eruptions, determine the peak-to-peak pressure, and to identify the active Etna crater [Ulivieri et al, 2013]. Processing of the I22FR and I48TN data is performed using the Progressive Multichannel Correlation (PMCC) algorithm [Cansi, 1995].…”

Section: Infrasound Measurements and Data Processing Techniquesmentioning

confidence: 99%

Evaluation of wind and temperature profiles from ECMWF analysis on two hemispheres using volcanic infrasound

et al. 2014

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In this paper, we evaluate vertical wind and temperature profiles that are produced by the European Centre for Medium‐Range Weather Forecasts (ECMWF) atmospheric analysis. The evaluation is carried out on both hemispheres: we make use of stratospheric infrasound arrivals from Mount Etna (37°N) and Mount Yasur (22°S). The near‐continuous, high activity of both volcanoes permits the study of stratospheric propagation along well‐defined paths with a time resolution ranging from hours to multiple years. Infrasound observables are compared to theoretical estimates obtained from acoustic propagation modeling using the ECMWF analysis. While a first‐order agreement is found for both hemispheres, we report on significant discrepancies around some of the equinox periods and other intervals during which the atmosphere is in a state of transition and dynamical oscillations of the atmosphere dominate over the general circulation. We present an inversion study in which we make use of measured trace velocity estimates to estimate first‐order effective sound speed model updates in a Bayesian framework. Deviations from the a priori models around the stratopause up to 10% (≈ 30 m s−1) are estimated. Such updates are in line with the results from comparisons between ECMWF analysis and observations from lidar and microwave Doppler spectroradiometer facilities that were colocated during the course of the 2012–2013 Atmospheric dynamics Research and InfraStructure in Europe (ARISE) measurement campaign.

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An automatic seismic event processing for detection and location: The P.M.C.C. Method

Cited by 353 publications

References 1 publication

The source of infrasound associated with long‐period events at Mount St. Helens

The source of infrasound associated with long‐period events at Mount St. Helens

Use of hydroacoustic and seismic arrays to observe rupture propagation and source extent of the M_w = 9.0 Sumatra earthquake

Evaluation of wind and temperature profiles from ECMWF analysis on two hemispheres using volcanic infrasound

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An automatic seismic event processing for detection and location: The P.M.C.C. Method

Cited by 353 publications

References 1 publication

The source of infrasound associated with long‐period events at Mount St. Helens

The source of infrasound associated with long‐period events at Mount St. Helens

Use of hydroacoustic and seismic arrays to observe rupture propagation and source extent of the Mw = 9.0 Sumatra earthquake

Evaluation of wind and temperature profiles from ECMWF analysis on two hemispheres using volcanic infrasound

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Use of hydroacoustic and seismic arrays to observe rupture propagation and source extent of the M_w = 9.0 Sumatra earthquake