SUMMARY Single-component ring lasers have provided high-resolution observations of Earth’s rotation rate as well local earthquake- or otherwise-induced rotational ground motions. Here, we present the design, construction and operational aspects ROMY, a four-component, tetrahedral-shaped laser installed at Geophysical Observatory Fürstenfeldbruck near Munich, Germany. Four equilateral, triangular-shaped with 12 m side length provide motions that can be combined to construct complete vector...

ABSTRACT The additional observation of three components rotational ground motions has benefits for tilt-seismometer coupling (e.g., ocean-bottom seismometry and volcano seismology), local site characterization, wavefield separation, source inversion, glacial planetary seismology, as well the monitoring structural health. Field applications have been mostly hampered by lack portable sensors with appropriate broadband operation range weak-motion sensitivity. Here, we present field observations...

We present a methodology to invert seismic data for localized area by combining source-side wavefield injection and receiver-side extrapolation method. Despite the high resolving power of full waveform inversion, computational cost practical scale elastic or viscoelastic inversion remains heavy burden. This can be much more severe time-lapse surveys, which require real-time imaging on daily weekly basis. Besides, changes structure during surveys are likely occur in small rather than whole...

A novel acquisition and processing technique is described to derive surface-wave dispersion curves from seismic ambient noise. We have determined that the use of spatial gradients wavefield provides new opportunities for high-resolution near-surface characterization with minimal field effort. In contrast conventional active source data analysis spatially smoothed results large dense arrays receivers, our method local phase velocity information noise using only three closely spaced geophones....

Abstract Back azimuth (BAz) information can be determined from combined measurements of rotations and translations at a single site. Such six degree‐of‐freedom (6‐DoF) are reasonably stable in delivering similar compared to small‐scale array three‐component seismometers. Here we investigate whether 6‐DoF approach is applicable tracking seismic sources. While common approaches determining the timing location energy sources generating waves rely on P‐waves, here use S‐waves. We track back...

SUMMARY We investigate the potential of multicomponent, single-point ground-motion observations (displacement, rotation and strain) to allow estimation near-receiver anisotropic elastic parameters. Based on full-space, plane-wave propagation analysis, we demonstrate that in (locally homogeneous) media, wave direction velocities quasi-P quasi-S waves can—in principle—be determined from three components displacements rotations. Mimicking situation a borehole setting, formulate an inverse...

Image feature matching is essential in many computer vision applications, and the foundation of detection, which a crucial quantification process. This manuscript focused on detecting more features from underwater acoustic imageries for further ocean engineering applications autonomous vehicles (AUVs). Currently, mainstream detection operators are developed optical images, there not yet detector oriented to imagery. To better analyze suitability existing detectors imagery develop an operator...

<abstract> <p>Many real-world problems can be classified as multimodal optimization (MMOPs), which require to locate global optima more possible and refine the accuracy of found high possible. When dealing with MMOPs, how divide population obtain effective niches is a key balance diversity convergence during evolution. In this paper, self-organizing map (SOM) based differential evolution dynamic selection strategy (SOMDE-DS) proposed improve performance (DE) in solving MMOPs....

A novel acquisition and processing technique is described to derive surface-wave dispersion curves from seismic ambient noise. We show that the use of spatial gradients wavefield provides new opportunities for high-resolution near-surface characterization with minimal field effort. In contrast conventional active source data analysis spatially smoothed results large dense arrays receivers, our method local phase velocity information using only three closely spaced geo-phones. time-frequency...

Summary In this paper, we study quantitatively the influence of seismic wavelet amplitude error on different scale anomaly inversion in frequency-domain full waveform (FWI). We design 40 models with size and 8 perturbation wavelets, evaluate reconstructed model by calculating optimal similarity coefficient fitting error. Tests show that when is larger than 30%, FWI obtains completely incorrect unacceptable inverted results even if initial just true model. addition, utilization transmission...

Single-component ring lasers have provided high-resolution observations of Earth's rotation rate as well local earthquake- or otherwise-induced rotational ground motions. Here we present the design, construction, and operational aspects ROMY, a four-component, tetrahedral-shaped laser installed at Geophysical Observatory Fürstenfeldbruck near Munich, Germany. Four equilateral, triangular-shaped with 12 m side length provide motions that can be combined to construct complete vector from point...

This study investigates the use of six-component (6C) seismic measurements for tracking moving traffic sources. We employ a collocated seismometer and rotational sensor to simultaneously capture both translational ground motions induced by vehicle Our research demonstrates novel method determining source directionality using single 6C station. station has small footprint, but it also allows us extract directional information from Rayleigh Love waves. To validate our approach, we compare...

In the context of ageing infrastructure, structural health monitoring is crucial for safety and integrity assessment, as well planning preventive maintenance. While classical methods rely on single-component sensors to track vibrations identify changes, this paper proposes an alternative approach real-time, continuous seismic monitoring. Our system uses collocated triaxial seismometers rotational (six-component or 6C measurements). a validation experiment, we simulate damage through...

We present a methodology to invert seismic data for localized area by combining source-side wavefield injection and receiver-side extrapolation method. Despite the high resolving power of full waveform inversion (FWI), computational cost practical scale elastic FWI remains heavy burden. This can be much more severe time-lapse surveys, which require real-time imaging on daily or weekly basis. Besides, structure changes during surveys are likely occur in small rather than whole region, such as...

In the past decade, significant progress has been made in acquisition and processing of seismic wavefield gradient data (e.g., recordings ground strain rotation). When combined with conventional multicomponent data, gradients enable estimation local properties wave speed, propagation direction, type) reconstruction spatially under-sampled wavefields. However, seismological community yet to embrace as a new observable.We present TwistPy (Toolbox for Wavefield Inertial Sensing Techniques), an...

Seismic full-waveform inversion (FWI) is a powerful method used to estimate the elastic properties of subsurface. To mitigate nonlinearity and cycle-skipping problems, in hierarchical manner, one first inverts low-frequency content determine long- medium-wavelength structures then increases frequency obtain detailed information. However, higher frequencies can be computationally very expensive, especially when target interest, such as oil/gas reservoirs axial melt lens, at great depth, far...

<p>The analysis of the relative amplitudes a passing seismic wave recorded on single seismometer measuring six degrees freedom ground motion (translation and rotation) theoretically allows one to extract information that can conventionally only be obtained from receiver arrays. In past, it has been shown numerical data extension conventional three-component (3C) polarization techniques six-components, unambiguously identify type characterise in terms its propagation direction...

Summary We present a methodology to invert seismic data for localised area by combining source-side wavefield injection and receiver-side extrapolation method. Despite the high resolving power of full waveform inversion (FWI), computational cost practical scale elastic FWI remains heavy burden. This can be much more severe time-lapse surveys, which require real-time imaging on daily or weekly basis. Besides, structure changes during surveys are likely occur in small rather than whole region,...

<p>The ROMY ring laser was constructed with 4 non-orthogonal triangular-shaped cavities of 12 m side length in the Geophysical Observatory outside Munich, Germany, 2016. The large dimensions individual rings have benefit allowing high sensitivity surpassing principle G-ring at Fundamentalstation Wettzell. However, concrete construction is geometrically less stable than that built on a rigid Xerodur plate. Each four has its own Sagnac frequency. horizontal triangular top...

Back azimuth (BAz) information can be determined from combined measurements of rotations and translations at a single site. Such six degree-of-freedom (6-DoF) are reasonably stable in delivering similar compared to small-scale array three-component seismometers. Here we investigate whether 6-DoF approach is applicable tracking seismic sources. While common approaches determining the timing location energy sources generating waves rely on P-waves, here use S-waves. We track back azimuths...

Summary We present a novel methodology for inverting 3D elastic time-lapse data local target structures of the Earth's interior. Since we are particularly interested in small property change deep region, extrapolate sources and receivers on surface to virtual vicinity region interest, order facilitate stabilise full waveform inversion (FWI) scheme. The key is i) finite-difference injection method (FDIM) source representation onto region; ii) wavefield extrapolation (WE) receiver side, which...

The preservation of discontinuous edges in seismic dataset such as faults, fractures, pinch-outs, channels and salt bodies while attenuating random noise is great significance for the following data interpretation. Noise reduction using inversion with total variation (TV) regularization a kind 2D edge-preserving filtering method. However, TV only limited to data. In this paper, we extend method 3D case by firstly taking difference along different directions, then performing Cauchy...

Observing motion within a building in six degrees of freedom (three components translational plus three rotational motion) opens completely new approaches to structural health monitoring. Inspired by inertial navigation, we can monitor the absolute or parts it without need for an external reference. Rotational sensors directly measure harmful torsional modes building, which has always been challenging and prone errors when using translation only. Currently, are developing methodologies...

Summary Full waveform inversion often suffers from the cycle-skipping problem, mainly because of absence low frequencies in seismograms, especially for elastic media. To address this issue, we present an reflection full (ERFWI) methodology. However, ERFWI, high nonlinearity still exists data residuals related misfit function, when true amplitude migration is not adopted. further relax cycle skipping and to meet requirements migration, develop a traveltime-based ERFWI method update...