scholarly journals Retrieving surface waves from ambient seismic noise using seismic interferometry by multidimensional deconvolution

2015 ◽  
Vol 120 (2) ◽  
pp. 944-961 ◽  
Author(s):  
Karel N. Dalen ◽  
T. Dylan Mikesell ◽  
Elmer N. Ruigrok ◽  
Kees Wapenaar
Keyword(s):  
Surface Waves ◽  
Seismic Noise ◽  
Seismic Interferometry ◽  
Ambient Seismic Noise

The Search of Diffusive Properties in Ambient Seismic Noise

2021 ◽  
Author(s):  
José Piña-Flores ◽  
Martín Cárdenas-Soto ◽  
Antonio García-Jerez ◽  
Michel Campillo ◽  
Francisco J. Sánchez-Sesma
Keyword(s):  
Green’S Function ◽  
Surface Waves ◽  
Green's Function ◽  
Seismic Noise ◽  
Elastic Field ◽  
Spectral Ratio ◽  
Ambient Seismic Noise ◽  
Data Sets ◽  
Original Experiment ◽  
Imaging Theory

ABSTRACT Ambient seismic noise (ASN) is becoming of interest for geophysical exploration and engineering seismology, because it is possible to exploit its potential for imaging. Theory asserts that the Green’s function can be retrieved from correlations within a diffuse field. Surface waves are the most conspicuous part of Green’s function in layered media. Thus, the velocities of surface waves can be obtained from ASN if the wavefield is diffuse. There is widespread interest in the conditions of emergence and properties of diffuse fields. In the applications, useful approximations of the Green’s function can be obtained from cross correlations of recorded motions of ASN. An elastic field is diffuse if the background illumination is azimuthally uniform and equipartitioned. It happens with the coda waves in earthquakes and has been verified in carefully planned experiments. For one of these data sets, the 1999 Chilpancingo (Mexico) experiment, there are some records of earthquake pre-events that undoubtedly are composed of ASN, so that the processing for coda can be tested on them. We decompose the ASN energies and study their equilibration. The scheme is inspired by the original experiment and uses the ASN recorded in an L-shaped array that allows the computation of spatial derivatives. It requires care in establishing the appropriate ranges for measuring parameters. In this search for robust indicators of diffusivity, we are led to establish that under certain circumstances, the S and P energy equilibration is a process that anticipates the diffusion regime (not necessarily isotropy), which justifies the use of horizontal-to-vertical spectral ratio in the context of diffuse-field theory.

Rayleigh group velocity extraction from ambient seismic noise to map the south Eastern Cape Karoo region, South Africa

2017 ◽  
Vol 120 (3) ◽  
pp. 341-350 ◽  
Author(s):  
L.J. Bezuidenhout ◽  
M. Doucouré ◽  
V. Wagener ◽  
M. de Wit ◽  
A. Mordret ◽  
...  
Keyword(s):  
South Africa ◽  
Surface Waves ◽  
Group Velocity ◽  
Seismic Noise ◽  
Vertical Component ◽  
Ambient Seismic Noise ◽  
Seismic Signals ◽  
The South ◽  
Velocity Anomaly ◽  
Rayleigh Surface Waves

Abstract The Karoo region of South Africa is an ideal laboratory to use ambient seismic signals to map the shallow subsurface, as it is a quiet and pristine environment with a geology that is relatively well known. Ambient seismic signals were continuously recorded for a ten week period between August and October 2015. The ambient seismic noise network consisted of two groups of 17 temporary, stand-alone seismic stations each. These were installed in the southeastern Cape Karoo region, near the town of Jansenville. Here we present data on the retrieval and coherency of Rayleigh surface waves extracted from the vertical component recordings. We reconstruct and show, for the first time in the southeastern Cape Karoo, estimates of Green's function from cross-correlating ambient noise data between stations pairs, which can be successfully used to image the subsurface. The stacked cross-correlations between all station pairs show clear arrivals of the Rayleigh surface waves. The group velocities of the Rayleigh waves in the 3 to 7 seconds period range were picked and inverted to compute the 2-D group velocity maps. The resulting 2-D group velocity maps at different periods resulted in a group velocity model from approximately 2 to 7 km depth, which shows a high velocity anomaly in the north of the study area, most likely imaging the denser, thick sedimentary basin of the Karoo (Carboniferous-Permian). To the south, the low velocity anomaly could correspond to the overlying Jurassic-Cretaceous sedimentary sequences of the younger Algoa Basin (Uitenhage Group).

scholarly journals Seismic Interferometry by cross‐correlation and by multi‐dimensional deconvolution using ambient seismic noise

2009 ◽  
Author(s):  
Jan Thorbecke ◽  
Elmer Ruigrok ◽  
Deyan Draganov ◽  
Joost v.d. Neut ◽  
Jürg Hunziker ◽  
...  
Keyword(s):  
Seismic Noise ◽  
Cross Correlation ◽  
Seismic Interferometry ◽  
Ambient Seismic Noise

scholarly journals Refinements to the method of epicentral location based on surface waves from ambient seismic noise: introducing Love waves

2012 ◽  
Vol 191 (2) ◽  
pp. 671-685 ◽  
Author(s):  
Anatoli L. Levshin ◽  
Mikhail P. Barmin ◽  
Morgan P. Moschetti ◽  
Carlos Mendoza ◽  
Michael H. Ritzwoller
Keyword(s):  
Surface Waves ◽  
Seismic Noise ◽  
Love Waves ◽  
Ambient Seismic Noise ◽  
Epicentral Location

Seismic Monitoring of Permafrost in Svalbard, Arctic Norway

2021 ◽  
Author(s):  
Julie Albaric ◽  
Daniela Kühn ◽  
Matthias Ohrnberger ◽  
Nadège Langet ◽  
Dave Harris ◽  
...  
Keyword(s):  
Surface Waves ◽  
Seismic Noise ◽  
Green's Functions ◽  
Seismic Velocity ◽  
Green’S Functions ◽  
Velocity Model ◽  
Body Waves ◽  
Ambient Seismic Noise ◽  
Seasonal Temperature ◽  
Velocity Variations

Abstract We analyze data from passive and active seismic experiments conducted in the Adventdalen valley of Svalbard in the Norwegian Arctic. Our objective is to characterize the ambient wavefield of the region and to investigate permafrost dynamics through estimates of seismic velocity variations. We are motivated by a need for early geophysical detection of potentially hazardous changes to permafrost stability. We draw upon several data sources to constrain various aspects of seismic wave propagation in Adventdalen. We use f-k analysis of five years of continuous data from the Spitsbergen seismic array (SPITS) to demonstrate that ambient seismic noise on Svalbard consists of continuously present body waves and intermittent surface waves appearing at regular intervals. A change in wavefield direction accompanies the sudden onset of surface waves when the average temperature rises above the freezing point, suggesting a cryogenic origin. This hypothesis is supported further by our analysis of records from a temporary broadband network, which indicates that the background wavefield is dominated by icequakes. Synthetic Green’s functions calculated from a 3D velocity model match well with empirical Green’s functions constructed from the recorded ambient seismic noise. We use a shallow shear-wave velocity model, obtained from active seismic measurements, to estimate the maximum depth of Rayleigh wave sensitivity to changes in shear velocity to be in the 50–100 m range. We extract seasonal variations in seismic velocities from ambient noise cross-correlation functions computed over three years of SPITS data. We attribute relative velocity variations to changes in the ice content of the shallow (2–4 m depth) permafrost, which is sensitive to seasonal temperature changes. A linear decreasing trend in seismic velocity is observed over the years, most likely due to permafrost warming.

scholarly journals Application of seismic interferometry by multidimensional deconvolution to ambient seismic noise recorded in Malargüe, Argentina

2016 ◽  
Vol 208 (2) ◽  
pp. 693-714 ◽  
Author(s):  
Cornelis Weemstra ◽  
Deyan Draganov ◽  
Elmer N. Ruigrok ◽  
Jürg Hunziker ◽  
Martin Gomez ◽  
...  
Keyword(s):  
Seismic Noise ◽  
Seismic Interferometry ◽  
Ambient Seismic Noise
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