IRIS Webinar in Spanish on YouTube:
El “Phase Weighted Stack” y el “Phase Cross-Correlation” para la extracción de señal en ruido sísmico .
Ambient Seismic Noise Analysis / Monitoring (primary and secondary microseisms, GEOSCOPE global seismic
network, seasonal variations of the noise, amplitude spectra, noise polarization, degree of elliptical polarization, climate impact,
Northern/Southern Hemisphere, monitoring Antarctica ice changes, deep water SM in North Atlantic using tide modulations,
SM from polarization analysis for Indian Ocean, SPSP Archipelago in equatorial Atlantic, ... ):
Stutzmann et al., 2009;
Schimmel et al., 2011b;
Beucler et al., 2015;
Davy et al., 2015;
de Queiroz et al., 2017.
Efficient Signal Extraction from Ambient Noise Cross-correlations (time-frequency domain phase weighted stack,
phase cross-correlations, development, Green's functions, time and frequency domain normalization, GEOSCOPE, TAPAS array,
body waves (P-phases), surface waves (R1, R2), wavelets, resampling, dispersion measurements, ...):
Schimmel et al., 2011a ;
Schimmel et al., 2017 ;
Ventosa et al., 2017 .
Monitoring Subtle Medium Changes (hydromechanical changes, precursors to volcanic erruption, El Hierro, small earthquake swarm,
phase cross-correlations and auto-correlations, ...):
D'Hour et al., 2015 ;
Sanchez-Pastor et al., 2018.
Generation Mechanisms, Observations and Modelling Seismic Noise (generation of secondary microseisms, Longuet-Higgins (1950) & Hasselmann (1963),
numerical ocean wave model WAVEWATCH III + improvements (ice berg distribution, coastal reflections, parametrization,
..., see IOWAGA), GEOSCOPE, synthetic noise power spectra of seismic displacement, modelling noise spectra for several years, deep water sources,
theoretical development, array analyses, noise amplitudes, ...):
Mainly Rayleigh waves:
Ardhuin et al., 2011 ;
Stutzmann et al., 2012 ;
Obrebski et al., 2012 ;
Gualtieri et al., 2013 ;
Sergeant et al., 2013 .
Mainly body waves:
Obrebski et al., 2013 ;
Gualtieri et al., 2014 ;
Farra et al., 2016;
Meschede et al., 2017;
Meschede et al., 2019.
Ambient noise tomography (Rayleigh-Wave, Group-Velocity Maps of the Borborema Province (NE Brazil) and SW Iberia, global scale
group velocity maps and 3-D inversion):
Carreiro-Dias et al., 2015;
Haned et al., 2016;
Corela et al., 2017;
Poveda et al., 2018.
Necessary Condition in Seismic Interferometry (theoretical development, noise cross-term cancellation,
how much averaging needed? length of correlation windows and number of stacks, monitoring noise non-stationarity, analytic approach):
Medeiros et al., 2015
Statistical redundancy of instantaneous phases (theoretical development, instantaneous phase coherence statistics,
instantaneous phase randomness characterization, noise cross-correlations, monitoring/characterizing ambient noise wavefield):
Gaudot et al., 2016.
Measuring group velocities (robustly measure group velocities, time-frequency domain phase-weighted stack combined with data resampling and decision strategies):
Schimmel et al., 2017.
Signal Detection, Noise Attenuation, Filter Design, Theory and Applications:
Semi-automated group velocity determination (time-scale domain, resampling strategy,
analytic signals, phase coherence, robust group arrival detections/measurements ...):
Schimmel et al., 2017 .
Lateral Phase-Coherence Filter (time-frequency domain, inverse S-transform,
analytic signals, phase coherence, spatial averaging, array analysis, ...):
Schimmel and Gallart, 2007 .
S-Transform versus Morlet Wavelet Transform
(new insights, comparisons and relations, ...):
Ventosa et al., 2008.
(motivation, new strategy, comparison, examples, numerical realization, ...):
Schimmel and Gallart, 2005, 2007
Simon et al., 2007 .
Window Length for Local Slant Stack Transform
(Adative optimum slowness resolution, derivation, examples, ...):
Ventosa et al., 2012 .
(rewriting the TT-transform in a new and more direct way, giving an interpretation of its diagonal elements):
Simon et al. (2008) .
Time-Frequency Domain Degree of Polarization Filter
(time-frequency domain, spectral matrix, time,frequency and distance-slowness
dependent averaging of degree of polarization, ...):
Schimmel and Gallart, 2004 .
Time-Domain Degree of Polarization Filter
(time domain, complex trace analysis, instantaneous polarization, comparison to eigen
approaches, covariance matrix, trade-off window
length and power, local slowness-dependent averaging of seismic polarization attributes,
Schimmel and Gallart, 2003 .
Phase Cross-Correlations (PCC) (design of new amplitude-unbiased correlation,
comparison to other methods, upper mantle discontinuities in Brazil
(220km, 410km, 510km, 660km), transition zone, examples, ...):
Schimmel, 1999 ,
summary with selected examples (HTML)
Phase Weighted Stacking (PWS) (analytic signals, phase coherence, amplitude-unbiased
coherence measure, non-linear stacking, vespagram, upper mantle discontinuities
(410km, 660km), transition zone, examples, ... ):
Schimmel and Paulssen, 1997 .
Examples: Note that there are very nice observations/applications published by
many other researchers.
Dam Collapse & Mud Flow
Mine Tailings Dam Collapse at Mariana (SE Brazil, 05/11/2015) (small magnitude earthquake sequence,
spatio-temporal relation of earthquakes and dam failure, seismic signals from mudflow,...)
Agurto-Detzel et al., 2016 ,
Regional Body Wave Tomography (P-waves, S-waves, Brazil, robustness and resolution
analyses, tectonics, upper mantle, ...):
Schimmel et al., 2003,
summary with selected examples (HTML),
Rocha et al., 2011, Simoes Neto et al., 2019. ,
P-wave and S-wave velocity model published in Schimmel et al. (2003) :
models (tar & bzip2 file) See end of this webpage for further information.
Correlation Between Intraplate Seismicity and Tomography in SE and central Brazil (P-waves, Brazil,
no correlation of seismic areas with main geological provinces, higher seismic activity
in areas with low P-wave velocities at 150-250 km depth, intraplate force concentration in upper
crust, high seismicity in regions of thinner lithosphere, ...):
Assumpção et al., 2004,
Rocha et al., 2016.
Regional and Global Ambient noise tomography (Rayleigh-wave, group-velocity maps of the Borborema Province, NE Brazil; global
scale group velocity maps and 3-D inversion; regional tomography, SW Iberia integrating seafloor- and
land-based data for group velocity maps and 3-D inversions; regional tomography, group velocities and 3-D inversions for Colombian Andes):
Carreiro-Dias et al., 2015;
Haned et al., 2016 ;
Corela et al., 2017;
Poveda et al., 2018.
Basin Discontinuities Through Ambient Noise Auto/Cross-correlations (Ebro Basin, Spain; Potiguar Basin, Brazil):
Romero and Schimmel, 2018;
Dantas et al., 2018.
Basin Discontinuities Through Reverse Time Migration (Solimoes Basin, Amazon, Brazil; different image conditions, phase cross-correlation):
Costa et al., 2018.
Moho Discontinuity Through Receiver Functions and Ambient Noise Cross/Auto-Correlations, Rayleigh Wave Dispersion Analyses (Isla Grande of Tierra del Fuego, Argentina):
Buffoni et al., 2018;
Buffoni et al., 2019.
Upper Mantle Discontinuities:
Upper Mantle Discontinuities (Detection and identification of coda waves which have
been converted and/or reflected at upper mantle discontinuities):
Schimmel and Paulssen, 1997;
Schimmel and Gallart, 2007.
410-km and 660-km Discontinuities beneath Spain and Morocco (Detection and identification of coda waves which have
been converted and/or reflected at upper mantle discontinuities, Eurasian-African Plate boundary at south Spain and north Morocco, cross-correlations, TopoIberia, Alboran slab, constraints on temperature and composition, depth profiles, ...):
Bonatto et al., 2013;
Bonatto et al., 2015
Lower Mantle Discontinuities:
D" Discontinuities (Detection and identification of ScS (sScS and ScS2) precursors,
focussing analysis to explain waveforms, modelling waveform variability and amplitudes,
synthetic seismograms, Kirchhoff-Helmholtz theory.)
Schimmel and Paulssen, 1996
Climate Reconstructions from Geological Measurements:
Rainfall Reconstruction Through Annually Laminated Lake Sediments
(Rainfall reconstruction, Iberian Peninsula, Calcite laminated sediment, North Atlantic Oscillation
periodograms, climate variability,...):
Romero-Viana et al., 2011.
Bio-Medical Rhythm Detection, Theory and Applications:
(analysis of circadian and ultradian rhythmicities, premature babies, incubator, insulated skin
temperature, environmental influence, folding algorithm, phasor walk out method,
Schimmel et al., 2002
Activity of Cave Crickets (Strinatia brevipennis)
(analysis of rhythmicities through different methods, new phase weighted folding algorithm,
evidence for circadian rhythmicities, isolation of environmental influence, controlled variation of
environmental influences, ...):
Hoenen et al., 2001.
Bio-Medical Rhythm Detection
(non-sinoidal rhythms, new folding algorithm, Lomb-Scargle
periodograms, benefits and limitations, unequally spaced data, ...):