Radiated energy estimations from finite‐fault earthquake slip models

Senatorski, Piotr

doi:10.1002/2014gl060013

Cited by 6 publications

(9 citation statements)

References 20 publications

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“…2.1. Such effects can be important during large earthquakes, when the area of simultaneous slip is large and the rupture front propagates fast (Senatorski 2014). Their significance for the interplay between slow and fast fault movements, and for the fault stability conditions that lead to seismic or aseismic character of slip, is debatable.…”

Section: Discussionmentioning

confidence: 99%

Effect of Slip-Weakening Distance on Seismic–Aseismic Slip Patterns

Senatorski

2019

Pure Appl. Geophys.

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In order to explain the seismic-aseismic slip patterns observed on megathrust faults, numerical simulations were carried out using the quasi-dynamic asperity fault model with the slip-dependent friction and stress-dependent healing. Two friction law parameters, strength and slip-weakening distance, are interpreted in the subduction channel context. The parameters are treated as random fields with specified characteristics. Their distributions define heterogeneities of the interplate frictional coupling. The higher strength regions accumulate stresses, whereas the slip-weakening distance lengths control the stress release rates. The simulation results indicate that the slip-dependent asperity model reproduces key features of real megathrust fault behavior. First, stable and unstable slip movements can occur at the same locations, even if the friction parameters are fixed. Second, two rupture styles, single asperity breaks and wide, smooth, propagating rupture fronts, can be distinguished. The latter style is responsible for large slips near the free surface, where lower fault strengths are expected. The reason for these effects is that slip instabilities depend both on local friction and on the system stiffness, which is related to the slipping area size and distribution of slips. It is also shown that the high-strength interplate patches, such as subducted seamounts, can both promote and restrain large earthquakes, depending on the slip-weakening distance lengths.

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Section: Discussionmentioning

confidence: 99%

Effect of Slip-Weakening Distance on Seismic–Aseismic Slip Patterns

Senatorski

2019

Pure Appl. Geophys.

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“…Other approaches have also been used to calculate seismic energy, such as those based on finite-fault models (Ide, 2002;Venkataraman and Kanamori, 2004b;Senatorski, 2014). Ide (2002) calculated the radiated energy using an expression based on slip and stress on the fault plane.…”

Section: Introductionmentioning

confidence: 99%

“…Here, the moment rate function derived from kinematic inversion is used to calculate the E R . On the other hand, Senatorski (2014) used an overdamped dynam-ics approximation for estimating the radiated seismic energy. The accuracy of this method depends on the rupture history.…”

Section: Introductionmentioning

confidence: 99%

“…In both cases, the seismic energy depends on the slip, rupture time, and seismic moment. According to Senatorski (2014), in most cases, the radiated seismic energy estimated by integrating digital seismic waveforms (E R ) is in the following range: E U < E R < E O . Several seismic energy observations have been calculated and compiled in catalogs in the last 2 decades.…”

Section: Introductionmentioning

confidence: 99%

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Global seismic energy scaling relationships based on the type of faulting

Rodríguez-Pérez,

Zúñiga

2024

Solid Earth

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Abstract. We derived scaling relationships for different seismic energy metrics for earthquakes around the globe with MW > 6.0 from 1990 to 2022. The seismic energy estimations were derived with two methodologies, the first based on the velocity flux integration and the second based on finite-fault models. In the first case, we analyzed 3331 reported seismic energies derived by integrating far-field waveforms. In the latter methodology, we used the total moment rate functions and the approximation of the overdamped dynamics to quantify seismic energy from 231 finite-fault models (Emrt and EO, EU, respectively). Both methodologies provide compatible energy estimates. The radiated seismic energies estimated from the slip models and integration of velocity records are also compared for different types of focal mechanisms (R, reverse; R-SS, reverse–strike-slip; SS, strike-slip; SS-R, strike-slip–reverse; SS-N, strike-slip–normal; N, normal; and N-SS, normal–strike-slip), and then used to derive converting scaling relations among the different energy types. Additionally, the behavior of radiated seismic energy (ER), energy-to-moment ratio (ER/M0), and apparent stress (τα) for different rupture types at a global scale is examined by considering depth variations in mechanical properties, such as seismic velocities, rock densities, and rigidities. For this purpose, we used a 1-D global velocity model. The ER/M0 ratio is, based on statistical t tests, largest for strike-slip earthquakes, followed by normal-faulting events, with the lowest values for reverse earthquakes for hypocentral depths < 90 km. Not enough data are available for statistical tests at deeper intervals except for the 90 to 120 km range, where we can satisfactorily conclude that ER/M0 for R-SS and SS-R types is larger than for N-type faulting, which also conforms to the previous assumption. In agreement with previous studies, our results exhibit a robust variation in τα with the focal mechanism. Regarding the behavior of τα with depth, our results agree with the existence of a bimodal distribution with two depth intervals where the apparent stress is maximum for normal-faulting earthquakes. At depths in the range of 180–240 km, τα for reverse earthquakes is higher than for normal-faulting events. We find the trend EU > Emrt > EO for all mechanism types based on statistical t tests. Finite-fault energy estimations also support focal mechanism dependence of apparent stress but only for shallow earthquakes (Z < 30 km). The slip distribution population used was too small to conclude that finite-fault energy estimations support the dependence of average apparent stress on rupture type at different depth intervals.

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“…Finally, the inertia of the moving fault, physical processes like micro-branching of the rupture front and partial melting, to name a few (Kanamori and Brodsky 2004;Mulargia et al 2004;Kanamori and Rivera 2006), can lead to a final stress lower than the frictional one, resulting in the overshooting mechanism. There are still many open questions connected with rupture arresting mechanisms, like whether there is any correlation of the arresting mechanism with other parameters describing the rupture process, what is a role of fault heterogeneities in rupture arresting (Candela et al 2011;Senatorski 2014), what is the thermodynamics of the arresting mechanisms, to name a few. To answer such questions, knowledge of the dynamic stress drop is necessary.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Stress Drop for Selected Seismic Events at Rudna Copper Mine, Poland

Dębski

2018

Pure Appl. Geophys.

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In this paper, we report on an analysis of rupture processes of mining-induced events using the Empirical Green Function approach. The basic goal of this analysis is to estimate the dynamic stress drop-the quantity describing frictional forces at a slipping fault plane during the unstable part of an earthquake. The presented results cover 40 selected events with magnitude M w ranging between 2.1 and 3.6 occurring in the Rudna copper mine (Poland) between 1996 and 2006. The spatial extent of the seismic network operated by the mine enabled us to estimate not only the dynamic stress drop but also the rupture velocities for most of the events studied. The results are analyzed in terms of correlations of the ratio of static to dynamic stress drop with other parameters characterizing the rupture processes. We also pose a question about the conditions of occurrence of over-and undershooting stress drop mechanisms. For all but two events, the estimated dynamic stress drop ranges between 0.1 and 4 MPa and is dominated by lower values. There are only two exceptions when it reaches the level of the order of 10 MPa. The reliability of these two exceptional cases is low, however. The rupture velocity, needed for dynamic stress drop calculation, was estimated from observed directivity effects. The obtained values ranged between 0.2 and almost 0.9 shear wave velocity, with dominating low velocities. The ratio of static to dynamic stress drop does not clearly correlate with the seismic scalar moment, source radius estimated according to Madariaga's model, or static stress drop. It only positively correlates with the rupture velocity and ranges from values lower than 1 (undershooting mechanisms), mostly for slow events, up to values larger than 1 (overshooting mechanisms) for the majority of fast events. For all events with overshooting-type mechanisms, the estimated rupture velocity V r was larger than half of the S-wave velocity V s : On the other hand, for the undershooting-type events the associated rupture velocity was in most cases smaller than 0.6 V s and large rupture speed was observed only in a few cases for this type of events.

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Radiated energy estimations from finite‐fault earthquake slip models

Cited by 6 publications

References 20 publications

Effect of Slip-Weakening Distance on Seismic–Aseismic Slip Patterns

Effect of Slip-Weakening Distance on Seismic–Aseismic Slip Patterns

Global seismic energy scaling relationships based on the type of faulting

Dynamic Stress Drop for Selected Seismic Events at Rudna Copper Mine, Poland

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