Seismic waveform simulation for models with fluctuating interfaces

AbstractAn ensemble-based method for seismic inversion to estimate elastic attributes is considered, namely the iterative ensemble Kalman smoother. The main focus of this work is the challenge associated with ensemble-based inversion of seismic waveform data. The amount of seismic data is large and, depending on ensemble size, it cannot be processed in a single batch. Instead a solution strategy of partitioning the data recordings in time windows and processing these sequentially is suggested. This work demonstrates how this partitioning can be done adaptively, with a focus on reliable and efficient estimation. The adaptivity relies on an analysis of the update direction used in the iterative procedure, and an interpretation of contributions from prior and likelihood to this update. The idea is that these must balance; if the prior dominates, the estimation process is inefficient while the estimation is likely to overfit and diverge if data dominates. Two approaches to meet this balance are formulated and evaluated. One is based on an interpretation of eigenvalue distributions and how this enters and affects weighting of prior and likelihood contributions. The other is based on balancing the norm magnitude of prior and likelihood vector components in the update. Only the latter is found to sufficiently regularize the data window. Although no guarantees for avoiding ensemble divergence are provided in the paper, the results of the adaptive procedure indicate that robust estimation performance can be achieved for ensemble-based inversion of seismic waveform data.

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Southern California Earthquake Data Now Available in the AWS Cloud

Seismological Research Letters ◽

10.1785/0220210039 ◽

2021 ◽

Author(s):

Ellen Yu ◽

Aparna Bhaskaran ◽

Shang-Lin Chen ◽

Zachary E. Ross ◽

Egill Hauksson ◽

...

Keyword(s):

Southern California ◽

Data Availability ◽

First Year ◽

Earthquake Catalog ◽

High Data ◽

Seismic Waveform ◽

Challenges And Opportunities ◽

Amazon Web Services ◽

Computationally Intensive ◽

Earthquake Data

Abstract The Southern California Earthquake Data Center is hosting its earthquake catalog and seismic waveform archive in the Amazon Web Services (AWS) Open Dataset Program (s3://scedc-pds; us-west-2 region). The cloud dataset’s high data availability and scalability facilitate research that uses large volumes of data and computationally intensive processing. We describe the data archive and our rationale for the formats and data organization. We provide two simple examples to show how storing the data in AWS Simple Storage Service can benefit the analysis of large datasets. We share usage statistics of our data during the first year in the AWS Open Dataset Program. We also discuss the challenges and opportunities of a cloud-hosted archive.

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Evolution of the East Africa-Arabia plume head

10.5194/egusphere-egu21-1399 ◽

2021 ◽

Author(s):

Chiara Civiero ◽

Sergei Lebedev ◽

Nicolas L. Celli

Keyword(s):

East Africa ◽

Basic Mechanism ◽

Continental Lithosphere ◽

Gulf Of Aden ◽

Low Velocity ◽

Velocity Anomaly ◽

Seismic Waveform ◽

Igneous Provinces ◽

Lithospheric Plates ◽

Plate Reconstructions

Hot plumes rising from Earth&#8217;s deep mantle are thought to form broad plume heads beneath lithospheric plates. In continents, mantle plumes cause uplift, rifting and volcanism, often dispersed over surprisingly broad areas. Using seismic waveform tomography, we image&#160;a star-shaped, low-velocity anomaly centered at Afar and composed of three narrow branches: beneath East Africa, beneath the Gulf of Aden, and beneath the Red Sea and West Arabia, extending north to Levant. We interpret this anomaly as the seismic expression of interconnected corridors of hot, partially molten rock beneath the East Africa-Arabia region. The corridors underlie areas of uplift, rifting and volcanism and accommodate an integral, active plume head. Eruption ages and plate reconstructions indicate that it developed south-to-north, and tomography shows it being fed by three deep upwellings beneath Kenya, Afar and Levant.&#160;These results demonstrate the complex feedbacks between the continental-lithosphere heterogeneity and plume-head evolution.&#160;Star-shaped plume heads sprawling within thin-lithosphere valleys can account for the enigmatic dispersed volcanism in large igneous provinces and are likely to be a basic mechanism of plume-continent interaction.

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