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Source Depth and Mechanism Inversion at Teleseismic Distances Using a Neighborhood Algorithm

Marson-Pidgeon, K; Kennett, Brian; Sambridge, Malcolm

Description

We performed nonlinear waveform inversion for source depth, time function, and mechanism, by modeling direct P and S waves and corresponding surface reflections at teleseismic distances. This technique was applied to moderate size events, and so we make use of short period or broadband records, and utilize SV waveforms in addition to P and SH. For the inversion we used a direct search method called the neighborhood algorithm (NA), which requires just two control parameters to guide the search...[Show more]

dc.contributor.authorMarson-Pidgeon, K
dc.contributor.authorKennett, Brian
dc.contributor.authorSambridge, Malcolm
dc.date.accessioned2015-12-13T23:16:40Z
dc.date.available2015-12-13T23:16:40Z
dc.identifier.issn0037-1106
dc.identifier.urihttp://hdl.handle.net/1885/89529
dc.description.abstractWe performed nonlinear waveform inversion for source depth, time function, and mechanism, by modeling direct P and S waves and corresponding surface reflections at teleseismic distances. This technique was applied to moderate size events, and so we make use of short period or broadband records, and utilize SV waveforms in addition to P and SH. For the inversion we used a direct search method called the neighborhood algorithm (NA), which requires just two control parameters to guide the search in a conceptually simple manner, and is based on the rank of a user-defined misfit measure. We use a simple generalized ray scheme to calculate synthetic seismograms for comparison with observations, and show that the use of a derivative-free method such as the NA allows us to easily substitute more complex synthetics if necessary. The source mechanism is represented in two different ways; the superposition of a double-couple component with an isotropic component, and a general moment tensor with six independent components. Good results are obtained with both synthetic input data and real data. We achieve good depth resolution and obtain useful constraints on the source-time function and source mechanism, including an isotropic component estimate. Such estimates provide important discriminants between man-made events and earthquakes. We illustrate inversion with real data using two earthquakes, and in both cases the source parameter estimates compare well with the corresponding centroid moment tensor solutions. We also apply our technique to a known nuclear explosion and obtain a very shallow depth estimate and a large isotropic component.
dc.publisherSeismological Society of America
dc.sourceBulletin of the Seismological Society of America
dc.subjectKeywords: Algorithms; Earthquakes; Graph theory; Tensors; Teleseismic distances; Seismology; algorithm; earthquake mechanism; source parameters; teleseismic wave
dc.titleSource Depth and Mechanism Inversion at Teleseismic Distances Using a Neighborhood Algorithm
dc.typeJournal article
local.description.notesImported from ARIES
local.description.refereedYes
local.identifier.citationvolume90
dc.date.issued2000
local.identifier.absfor040407 - Seismology and Seismic Exploration
local.identifier.ariespublicationMigratedxPub19590
local.type.statusPublished Version
local.contributor.affiliationMarson-Pidgeon, K, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationKennett, Brian, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationSambridge, Malcolm, College of Physical and Mathematical Sciences, ANU
local.bibliographicCitation.issue6
local.bibliographicCitation.startpage1369
local.bibliographicCitation.lastpage1383
local.identifier.doi10.1785/0120000020
dc.date.updated2015-12-12T08:49:11Z
local.identifier.scopusID2-s2.0-0034451431
CollectionsANU Research Publications

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