Rapid determination of <i>P</i> wave‐based energy magnitude: Insights on source parameter scaling of the 2016 Central Italy earthquake sequence

Picozzi, Matteo; Bindi, Dino; Brondi, Piero; Giacomo, Domenico Di; Parolai, Stefano; Zollo, Aldo

doi:10.1002/2017gl073228

Cited by 24 publications

(24 citation statements)

References 68 publications

(63 reference statements)

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“…Also, the retrieved stress drop values are comparable with the ones from Bindi et al (2018a). Instead, they are significantly lower than the ones reported by Picozzi et al (2017) and…”

Section: Resultscontrasting

confidence: 71%

A probabilistic method for the estimation of earthquake source parameters from spectral inversion: application to the 2016–2017 Central Italy seismic sequence

Supino

Festa

Zollo

2019

Geophysical Journal International

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We develop a probabilistic framework based on the conjunction of states of information between data and model, to jointly retrieve earthquake source parameters and anelastic attenuation factor from inversion of displacement amplitude spectra. The evaluation of the joint probability density functions (PDFs) enables us to take into account between-parameter correlations in the final estimates of the parameters and related uncertainties. Following this approach, we first search for the maximum of the a-posteriori PDF through the basin hopping technique that couples a global exploration built on a Markov chain with a local deterministic maximization. Then we compute statistical indicators (mean, variance and correlation coefficients) on source parameters and anelastic attenuation through integration of the PDF in the vicinity of the maximum likelihood solution. Definition of quality criteria based on the signal to noise ratio and similarity of the marginal PDFs with a Gaussian function enable us to define the frequency domain for the inversion and to get rid of unconstrained solutions.We perform synthetic tests to assess theoretical correlations as a function of the signal to noise ratio and to define the minimum bandwidth around the corner frequency for consistent parameter resolution.As an application, we finally estimate the source parameters for the 2016-2017 Central Italy seismic sequence. We found that the classical scaling between the seismic moment and the corner frequency holds, with an average stress drop of 2.1 0.3 MPa     . However, the main events in the sequence exhibit a stress drop larger than the average value. Finally, the small seismic efficiency indicates a stress overshoot, possibly due to dynamic effects or large frictional efficiency. Short title : Probabilistic source parameters estimation

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“…Also, the retrieved stress drop values are comparable with the ones from Bindi et al (2018a). Instead, they are significantly lower than the ones reported by Picozzi et al (2017) and…”

Section: Resultscontrasting

confidence: 71%

A probabilistic method for the estimation of earthquake source parameters from spectral inversion: application to the 2016–2017 Central Italy seismic sequence

Supino

Festa

Zollo

2019

Geophysical Journal International

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“…Similar results for Italy were found by Bindi et al (2018), and for an earthquake early warning energy magnitude (i.e. derived on P-waves recorded at local scale) by Picozzi et al (2017b). The comparison among (Figs 2 and 4) highlights that the reduced δBe variability is mostly related to earthquakes (i.e.…”

Section: P E a K G Ro U N D V E L O C I T Y Va R I A B I L I T Y U S supporting

confidence: 81%

Moment and energy magnitudes: diversity of views on earthquake shaking potential and earthquake statistics

Picozzi

Bindi

Spallarossa

et al. 2018

Geophysical Journal International

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The size of an earthquake can be defined either from the seismic moment (M 0) or in terms of radiated seismic energy (E r). These two parameters look at the source complexity from different perspectives: M 0 is a static measure of the earthquake size, whereas E r is related to the rupture kinematics and dynamics. For practical applications and for dissemination purposes, the logarithms of M 0 and E r are used to define the moment magnitude M w and the energy magnitude M E , respectively. The introduction of M w and M E partially obscure the complementarity of M 0 and E r. The reason is due to the assumptions needed to define any magnitude scale. For example, in defining M w , the apparent stress (i.e. the ratio between M 0 and E r multiplied by the rigidity) was assumed to be constant, and under this condition, M w and M E values would only differ by an offset which, in turn, depends on the average apparent stress of the analysed data set. In any case, when the apparent stress is variable and, for example, scales with M 0 , the value of M E derived from M w cannot be used to infer E r. In this study, we investigate the similarities and differences between M w and M E in connection with the scaling of the source parameters using a data set of around 4700 earthquakes recorded at both global and regional scales and belonging to four data sets. These cover different geographical areas and extensions and are composed by either natural or induced earthquakes in the magnitude range 1.5 ≤ M w ≤ 9.0. Our results show that M E is better than M w in capturing the high-frequency ground shaking variability whenever the stress drop differs from the reference value adopted to define M w. We show that M E accounts for variations in the rupture processes, introducing systematic event-dependent deviations from the mean regional peak ground motion velocity scaling. Therefore, M E might be a valid alternative to M w for deriving ground motion prediction equations for seismic hazard studies in areas where strong systematic stress drop scaling with M 0 are found, such as observed for induced earthquakes in geothermal regions. Furthermore, we analyse the different data sets in terms of their cumulative frequency-magnitude distribution, considering both M E and M w. We show that the b values from M w (b Mw) and M E (b ME) can be significantly different when the stress drop shows a systematic scaling relationship with M 0. We found that b ME is nearly constant for all data sets, while b Mw shows an inverse linear scaling with apparent stress.

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“…The parameters IV2 S and PD S are linked to E r and M 0 through empirical attenuation models derived using data set D1, as detailed in the section Method (eqs 8 and 9 ). Since linear non-parametric regressions 19 are applied, the attenuation models are tables listing the attenuation coefficients for the discretized distance range. The attenuation models are reported in Table S1 .…”

Section: Resultsmentioning

confidence: 99%

“…Indeed, high energy-to-moment ratios indicate that the intensity of radiated energy at high frequencies is large relative to the size (measured by moment) of an earthquake, with significant implications on hazard assessment 17 . Although automatic procedures for the rapid estimation of M e using P-wave recordings have been proposed both at teleseismic 18 and local 19 distances, a strategy to combine the information provided by M w and M e for a rapid assessment of the damage potential of an earthquake has not been proposed yet.…”

Section: Introductionmentioning

confidence: 99%

A rapid response magnitude scale for timely assessment of the high frequency seismic radiation

Picozzi

Bindi

Spallarossa

et al. 2018

Sci Rep

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In this work the scaling of seismic moment (M0) and radiated energy (Er) is investigated for almost 800 earthquakes of the 2016–17 Amatrice-Norcia sequences in Italy, ranging in moment magnitude (Mw) from 2.5 to 6.5. The analysis of the M0-to-Er scaling highlights a breaking of the source self-similarity, with higher stress drops for larger events. Our results show the limitation of using M0, and in turn Mw, to capture the variability of the high frequency ground motion. Since the observed seismicity does not agree with the assumptions on stress drop in the definition of Mw, we exploit the availability of both Er and M0 to modify the definition of Mw and introduce a rapid response magnitude (Mr), which accounts for the dynamic properties of rupture. The new Mr scale allows us to improve the prediction of the earthquake shaking potential, as shown by the reduction of the between-event residuals computed for the peak ground velocity. The procedure we propose is therefore a significant step towards a quick assessment of earthquakes damage potential and timely implementation of emergency plans.

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Rapid determination of P wave‐based energy magnitude: Insights on source parameter scaling of the 2016 Central Italy earthquake sequence

Cited by 24 publications

References 68 publications

A probabilistic method for the estimation of earthquake source parameters from spectral inversion: application to the 2016–2017 Central Italy seismic sequence

A probabilistic method for the estimation of earthquake source parameters from spectral inversion: application to the 2016–2017 Central Italy seismic sequence

Moment and energy magnitudes: diversity of views on earthquake shaking potential and earthquake statistics

A rapid response magnitude scale for timely assessment of the high frequency seismic radiation

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