Spatio‐Temporal Evolution of Earthquake Static Stress Drop Values in the 2016–2017 Central Italy Seismic Sequence

Kemna, Kilian B.; Verdecchia, Alessandro; Harrington, R. M.

doi:10.1029/2021jb022566

Cited by 16 publications

(33 citation statements)

References 120 publications

(260 reference statements)

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“…Priors for the corner frequency f c of each event depend on the event size but are assumed to follow a lognormal distribution derived from a corresponding stress drop prior with a median stress drop of 5 MPa and standard deviation of 0.4 in log10 units. These values are in line with recent work (Baltay et al., 2013; Bindi, Zaccarelli, & Kotha, 2020; Kemna et al., 2021; Oth et al., 2017; Trugman, 2020), though the final inversion results are insensitive to the precise values selected (within reason). Seismic moment M 0 is also assumed lognormal and centered on the catalog value.…”

Section: Background and Methodologysupporting

confidence: 90%

“…Both the Ridgecrest (Trugman et al., 2020; X. Wang & Zhan, 2020) and the San Jacinto (Cheng et al., 2018; Ross, Rollins, et al., 2017) fault zones are structurally complex fault systems, yet differ in their source properties. Without any target events of note on the main strand of the San Andreas, it is difficult to fully assess the potential effects of fault geometry and maturity on source properties like stress drop (Chu et al., 2021; Kemna et al., 2021).…”

Section: Discussionmentioning

confidence: 99%

“…Moment adjustment: Kemna et al, 2021;Oth et al, 2017;Trugman, 2020), though the final inversion results are insensitive to the precise values selected (within reason). Seismic moment M 0 is also assumed lognormal and centered on the catalog value.…”

Section: Background and Methodologymentioning

confidence: 99%

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Resolving Differences in the Rupture Properties of M5 Earthquakes in California Using Bayesian Source Spectral Analysis

Trugman

2022

JGR Solid Earth

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Section: Background and Methodologysupporting

confidence: 90%

Section: Discussionmentioning

confidence: 99%

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Resolving Differences in the Rupture Properties of M5 Earthquakes in California Using Bayesian Source Spectral Analysis

Trugman

2022

JGR Solid Earth

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“…The comparison of the results in terms of source spectra and source parameters (Figs 11 and 12) allows us to confirm the robustness of source parameter estimation, as well as to validate the coda calibration in this region. The consistency of source parameters estimated from analysis performed on different portions of seismic recordings is also a matter of debate for Central Italy (Kemna et al 2021). Figs 11 and 12 show that coda and S waves methodologies applied independently to a common data set compiled for central Apennines in Italy provide very similar source spectra, from which consistent scaling laws are extracted.…”

Section: Discussion a N D C O N C L U S I O N Smentioning

confidence: 98%

“…Andrews 1986;Castro et al 1990;Boatwright et al 1991;Edwards et al 2008;Malagnini et al 2011;Oth et al 2011;Picozzi et al 2017;Trugman & Shearer 2017). Despite so many different novel approaches, it is rare that results from different methods focusing on the same data set yield similar results, and as such, the question of absolute stress drop and its scaling remains quite ambiguous, especially over a broad range of magnitudes (Shearer et al 2019;Kemna et al 2021).…”

Section: Introductionmentioning

confidence: 99%

Source scaling comparison and validation in Central Italy: data intensive direct Swaves versus the sparse data coda envelope methodology

Morasca

Bindi

Mayeda

et al. 2022

Geophysical Journal International

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Summary Robustness of source parameter estimates is a fundamental issue in understanding the relationships between small and large events, however it is difficult to assess how much of the variability of the source parameters can be attributed to the physical source characteristics or to the uncertainties of the methods and data used to estimate the values. In this study we apply the coda method by Mayeda et al. (2003) using the Coda Calibration Tool (CCT), a freely available Java-based code (https://github.com/LLNL/coda-calibration-tool) to obtain a regional calibration for Central Italy for estimating stable source parameters. We demonstrate the power of the coda technique in this region and show that it provides the same robustness in source parameter estimation as a data-driven methodology (GIT, Generalized Inversion Technique), but with much fewer calibration events and stations. The Central Italy region is ideal for both GIT and coda approaches as it is characterized by high-quality data including recent well-recorded seismic sequences such as L'Aquila (2009) and Amatrice-Norcia-Visso (2016–2017). This allows us to apply data-driven methods such as GIT, and coda-based methods that require few, but high-quality data. The dataset for GIT analysis includes ∼5000 earthquakes and more than 600 stations, while for coda analysis we used a small subset of 39 events spanning 3.5 < Mw < 6.33 and 14 well-distributed broadband stations. For the common calibration events, as well as an additional 247 events (∼1.7 < Mw<∼ 5.0) not used in either calibration, we find excellent agreement between GIT-derived and CCT-derived source spectra. This confirms the ability of the coda approach to obtain stable source parameters even with few calibration events and stations. Even reducing the coda calibration dataset by 75 per cent we found no appreciable degradation in performance. This validation of the coda calibration approach over a broad range of event size demonstrates that this procedure, once extended to other regions, represents a powerful tool for future routine applications to homogeneously evaluate robust source parameters on a national scale. Furthermore, the coda calibration procedure can homogenize the Mw estimates for small and large events without the necessity of introducing any conversion scale between narrowband measures such as local magnitude (ML) and Mw which has been shown to introduce significant bias (e.g. Shelly et al., 2022).

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Resolving Differences in the Rupture Properties of Prominent Earthquakes in Southern California with Bayesian Source Spectral Analysis

Trugman

2022

Preprint

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The spectra of earthquake waveforms can provide important insight into rupture processes, but the analysis and interpretation of these spectra is rarely straightforward. Here we develop a Bayesian framework that embraces the inherent data and modeling uncertainties of spectral analysis to infer key source properties. The method uses a spectral ratio approach to correct the observed waveform spectra of nearby earthquakes for path and site attenuation. The objective then is to solve for a joint posterior probability distribution of three source parameters -seismic moment, corner frequency, and high-frequency falloff rate -for each earthquake in the sequence, as well as a measure of rupture directivity for target events with good azimuthal station coverage. While computationally intensive, this technique provides a quantitative understanding of parameter tradeoffs and uncertainties and allows one to impose physical constraints through prior distributions on all source parameters, which guide the inversion when data is limited. We demonstrate the method by analyzing in detail the source properties of 14 different target events of magnitude M5 in southern California that span a wide range of tectonic regimes and fault systems. These prominent earthquakes, while comparable in size, exhibit marked diversity in their source properties and directivity, with clear spatial patterns, depth-dependent trends, and a preference for unilateral directivity. These coherent spatial variations source properties suggest that regional differences in tectonic setting, hypocentral depth or fault zone characteristics may drive variability in rupture processes, with important implications for our understanding of earthquake physics and its relation to hazard.

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Spatio‐Temporal Evolution of Earthquake Static Stress Drop Values in the 2016–2017 Central Italy Seismic Sequence

Cited by 16 publications

References 120 publications

Resolving Differences in the Rupture Properties of M5 Earthquakes in California Using Bayesian Source Spectral Analysis

Resolving Differences in the Rupture Properties of M5 Earthquakes in California Using Bayesian Source Spectral Analysis

Source scaling comparison and validation in Central Italy: data intensive direct Swaves versus the sparse data coda envelope methodology

Resolving Differences in the Rupture Properties of Prominent Earthquakes in Southern California with Bayesian Source Spectral Analysis

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