We present a narrative of the eruptive events culminating in cataclysmic January 15, 2022 eruption Hunga Tonga-Hunga Ha'apai Volcano by synthesizing diverse preliminary seismic, volcanological, sound wave, and lightning data available within first few weeks after occurred. The hour activity produced fast-propagating tsunami waves, long-period seismic loud audible infrasonic exceptionally intense volcanic an unsteady plume that transiently reached—at 58 ​km—the Earth's mesosphere. Energetic...

Some hydrocarbon reservoirs are trapped beneath salt bodies, where seismic imaging is greatly challenged due to poor illumination. Multiple reflections have different propagation wave paths from primary and thus can be used complement the illuminations not acquired. Consequently, migration of multiples sometimes provide better subsalt images compared conventional which uses only. In this paper, we propose modify reverse time so that as constructive reflection energy for imaging. This new...

Automatic identification of faults on seismic structural images is a challenging yet crucial task in quantitative interpretation. Human picking or attribute-based fault detection methods may misidentify noisy, complex images. We develop new automatic method using nested residual U-shaped convolutional neural network. Each the encoders and decoders this network U-Net, leading to architecture. The final map results from fusion three maps with low, medium, high resolutions. demonstrate...

High-fidelity fault detection on seismic images is one of the most important and challenging topics in field automatic interpretation. Conventional hand-picking-based semi-human-intervened fault-detection approaches are being replaced by fully methods thanks to development machine learning. We have developed a novel multiscale attention convolutional neural network (MACNN) improve machine-learning-based end-to-end images. The characteristics our MACNN method that it uses spatial-channel...

Reverse time migration (RTM) using multiples generates inherent crosstalk artifacts due to the interference among of different orders. We have developed a method remove such crosstalk. This approach first separates recorded seismic data into primary reflections and surface-related elimination algorithm then isolates can take any specified, say [Formula: see text]th, order as incident wave next higher data, ([Formula: text])th order, corresponding reflection for imaging. applied least-squares...

We demonstrate that higher order Fréchet derivatives are not negligible and the linear derivative may be appropriate in many cases, especially when forward scattering is involved for large-scale or strong perturbations (heterogeneities). then introduce derive non-linear partial including all acoustic wave equation. prove can realized by consecutive applications of operator a zero-order propagator to source. The full directly related series. formulation used non-linearly update model. It also...

Least-squares migration (LSM) can be effective to mitigate the limitation of finite-seismic acquisition, balance subsurface illumination, and improve spatial resolution image, but it requires iterations demigration obtain desired reflectivity model. The computational efficiency accuracy operators are crucial for applying algorithm. We have developed a test feasibility using Gaussian beam as wavefield extrapolating operator LSM, denoted least-squares migration. Our method combines advantages...

Naturally fractured reservoirs occur worldwide, and they account for the bulk of global oil production. The most important impact fractures is their influence on fluid flow. To maximize production, characterization a reservoir at scale an field very important. For transport, critical parameters are connectivity transmittivity plus orientation. These can be related to fracture spacing, compliance, orientation, which seismic rock physics models. We discovered new technique that invert...

Research Article| January 25, 2017 Crazyseismic: A MATLAB GUI‐Based Software Package for Passive Seismic Data Preprocessing Chunquan Yu; Yu aDepartment of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute Technology, Cambridge, 02139 U.S.A.yucq@gps.caltech.eduxuefeng.shang@gmail.com Search other works by this author on: GSW Google Scholar Yingcai Zheng; Zheng bDepartment Earth University Houston, Texas 77004 U.S.A.yc.zheng@gmail.com Xuefeng Shang Author Article Information...

Many full-waveform inversion schemes are based on the iterative perturbation theory to fit observed waveforms. When waveforms lack low frequencies, those may encounter convergence problems due cycle skipping when initial velocity model is far from true model. To mitigate this difficulty, we have developed a new objective function that fits seismic-waveform intensity, so dependence of starting can be reduced. The waveform intensity proportional square its amplitude. Forming using nonlinear...

Abstract Complex shear wave splitting (SWS) patterns in subduction zones are often interpreted geodynamically as resulting from complex mantle flow; however, this may not always be necessary. We analyzed 7,093 high‐quality SWS measurements teleseismic S waves recorded by Hi‐net stations across the Ryukyu arc Japan. Our findings show a systematic rotation of fast polarization trench‐parallel to trench‐perpendicular depending on earthquake backazimuth. For same earthquake, measured also vary...

Internal multiple reflections have different propagation paths than primary and surface-related multiples; thus, they can complement illumination where other waves are unavailable. Consequently, migration of internal multiples may provide vital images in the shadow zone reflections. We developed an approach to image structures with multiples. With this method, be separated used as data for reverse time migration. Instead applying imaging condition directly source receiver wavefields, we...

Traditional amplitude variation with offset and azimuth (AVOAz) analysis for fracture characterization extracts properties through of reflection AVOAz to determine anisotropic parameters (e.g., Thomsen’s parameters) that are then related properties. The validity this method relies on the basic assumption a fractured unit can be viewed as an equivalent medium. As rule thumb, is taken valid when spacing less than [Formula: see text]. Under effective medium assumption, diffractions from...

Characterizing and monitoring geologic formations around a borehole are crucial for energy environmental applications. However, conventional wireline sonic logging usually cannot be used in high-temperature environments nor is the tool feasible long-term monitoring. We introduce evaluate feasibility of source-free distributed-acoustic-sensing (DAS) method based on DAS ambient noise. Our new provides next-generation imaging tool. The source free because it uses ever-present noises as sources...

Abstract Understanding the forces and magma system dynamics on timescales of seconds to minutes remains challenging. In January 2022 phreatoplinian Hunga Tonga‐Hunga Ha'apai eruption, four remarkably similar seismic subevents within a 5‐min interval occurred during intensifying early eruptive phase. The are in waveforms durations (∼25 s each). Each subevent begins with an unusual negative P‐wave polarity which is inferred, using full‐wave modeling, be caused by upward single‐force mechanism...

Fracture characterization in an oil or gas reservoir is very important for field development and exploration because natural fracture systems can dominate the fluid drainage pattern a reservoir. Traditional seismic methods characterization, such as amplitude variations with offset azimuth shear wave birefringence, are based on equivalent medium theory assumption that dimensions spacing small relative to length, so fractured unit homogeneous anisotropic medium. However, fractures order of...

Abstract Seismic interpretation of subsurface structures is traditionally performed without any account flow behavior. Here we present a methodology for characterizing fractured geologic reservoirs by integrating and seismic data. The key element the proposed approach identification—within inversion—of intimate relation between fracture compliance transmissivity, which determine acoustic responses reservoir, respectively. Owing to strong (but highly uncertain) dependence transmissivity on...

We have developed a new propagator-matrix scheme to simulate seismic-wave propagation and scattering in multilayered medium containing karstic voids. The propagator matrices can be found using the boundary element method. model irregular boundaries, including arbitrary free-surface topography. Any number of karsts included model, each karst geometric shape. used Burton-Miller formulation tackle numerical instability caused by fictitious resonance due finite size void. Our method was...

Subduction zones play critical roles in the recycling of oceanic lithosphere and generation continental crust. Seismic imaging can reveal structures associated with key dynamic processes occurring upper-mantle wedge above sinking slab. Three-dimensional images reflecting interfaces throughout subducting Tonga slab were obtained by migration teleseismic recordings underside P- S -wave reflections. Laterally continuous weak reflectors tens kilometers topography detected at depths near 90, 125,...

Teleseismic ground motion recordings of deep earthquakes often contain clear seismic wave reflections from the free surface above source ( pP , sP sS ), with isolated precursors p M P s and S ) produced by underside Moho (the crust‐mantle boundary) below reflection points. The waveforms depth phases their are readily modeled, providing constraints, for steep angles incidence, on integrated two‐way crustal travel times shear compressional impedance contrasts earthquake regions. We model in...

PreviousNext No AccessSEG Technical Program Expanded Abstracts 2012Target-oriented Time-lapse Waveform Inversion using Virtual SurveyAuthors: Di YangYingcai ZhengMichael FehlerAlison MalcolmDi YangMIT, Yingcai ZhengMIT, Michael FehlerMIT, and Alison MalcolmMIThttps://doi.org/10.1190/segam2012-1308.1 SectionsSupplemental MaterialAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InReddit Abstract seismic data are widely used for...