A new version of "Boxer" code for the determination of seismic source parameters from macroseismic data

Geophysical Research Abstracts, Vol. 11, EGU2009-5699, 2009 EGU General Assembly 2009 © Author(s) 2009 A new version of "Boxer" code for the determination of seismic source parameters from macroseismic data. P. Gasperini (1), G. Vannucci (2), and D. Tripone (3) (1) Dipartimento di Fisica, Università di Bologna, Viale Berti-Pichat 8, I-40127 Bologna (Italy), [email protected], (2) INGV-Istituto Nazionale di Geofisica e Vulcanologia, Via Donato Creti, 12, I-40128, Bologna (Italy), ([email protected]), (3) INGV-Istituto Nazionale di Geofisica e Vulcanologia, Via Donato Creti, 12, I-40128, Bologna (Italy), ([email protected]) About ten years after the first release of the code we implemented new methods of epicentral location and magnitude computation as well as a procedure for the evaluation of uncertainties by the bootstrap technique. We also developed a user-friendly interface for parameter setup and graphical post-processing of the results. The improved code allows to locating epicenters in the sea or in uninhabited areas by minimizing the norm of the residuals of an attenuation equation. The same approach also per-mits, in the most favorable cases, the estimation of the source depth. By the geographical rendering of the bootstrap solutions we give a tool for characterizing the possible multiplicity of the seismic source of historical earthquakes

L’indagine macrosismica: metodologia, parametri del terremoto, questioni aperte

Subito dopo l’evento del 6 aprile 2009, come di consueto è stata realizzata una lunga e complessa indagine macrosismica, promossa dal gruppo operativo QUEST, che ha avuto inizialmente l’obiettivo di delimitare l’area di danneggiamento, a supporto delle attività di pronto intervento della Protezione Civile, e successivamente quello di classificare nel modo più accurato e capillare possibile, gli effetti prodotti dall’evento, particolarmente nelle aree danneggiate. A questo scopo è stata prodotta una stima utilizzando la scala MCS (Sieberg, 1930); in un secondo momento è stata rifinita l’indagine per una cinquantina di località dell’area maggiormente danneggiata (Is MCS>VII), raccogliendo ed elaborando i dati in termini di scala macrosismica EMS98 (Grünthal, 1998). Per la complessità e la dimensione dei problemi affrontati, questo terremoto ha costituito un banco di prova di grande importanza per la macrosismologia italiana. In questo testo viene descritto il lavoro realizzato, discutendo in particolare alcuni aspetti che hanno messo alla prova le metodologie di indagine tradizionali (sistematiche irregolarità degli insediamenti monitorati, forti divergenze degli scenari di danno rispetto a quelli previsti dalle scale, difficile comparabilità con scenari storici, ecc.) e presentandone i risultati, in relazione ai parametri epicentrali che ne risultano e il loro contributo più diretto alla comprensione complessiva della sismicità dell’area

L’indagine macrosismica: metodologia, parametri del terremoto, questioni aperte

Subito dopo l’evento del 6 aprile 2009, come di consueto è stata realizzata una lunga e complessa indagine macrosismica, promossa dal gruppo operativo QUEST, che ha avuto inizialmente l’obiettivo di delimitare l’area di danneggiamento, a supporto delle attività di pronto intervento della Protezione Civile, e successivamente quello di classificare nel modo più accurato e capillare possibile, gli effetti prodotti dall’evento, particolarmente nelle aree danneggiate. A questo scopo è stata prodotta una stima utilizzando la scala MCS (Sieberg, 1930); in un secondo momento è stata rifinita l’indagine per una cinquantina di località dell’area maggiormente danneggiata (Is MCS>VII), raccogliendo ed elaborando i dati in termini di scala macrosismica EMS98 (Grünthal, 1998). Per la complessità e la dimensione dei problemi affrontati, questo terremoto ha costituito un banco di prova di grande importanza per la macrosismologia italiana. In questo testo viene descritto il lavoro realizzato, discutendo in particolare alcuni aspetti che hanno messo alla prova le metodologie di indagine tradizionali (sistematiche irregolarità degli insediamenti monitorati, forti divergenze degli scenari di danno rispetto a quelli previsti dalle scale, difficile comparabilità con scenari storici, ecc.) e presentandone i risultati, in relazione ai parametri epicentrali che ne risultano e il loro contributo più diretto alla comprensione complessiva della sismicità dell’area.Published49-551.11. TTC - Osservazioni e monitoraggio macrosismico del territorio nazionaleN/A or not JCRope

A new version of "Boxer" code for the determination of seismic source parameters from macroseismic data

Geophysical Research Abstracts, Vol. 11, EGU2009-5699, 2009 EGU General Assembly 2009 © Author(s) 2009 A new version of "Boxer" code for the determination of seismic source parameters from macroseismic data. P. Gasperini (1), G. Vannucci (2), and D. Tripone (3) (1) Dipartimento di Fisica, Università di Bologna, Viale Berti-Pichat 8, I-40127 Bologna (Italy), [email protected], (2) INGV-Istituto Nazionale di Geofisica e Vulcanologia, Via Donato Creti, 12, I-40128, Bologna (Italy), ([email protected]), (3) INGV-Istituto Nazionale di Geofisica e Vulcanologia, Via Donato Creti, 12, I-40128, Bologna (Italy), ([email protected]) About ten years after the first release of the code we implemented new methods of epicentral location and magnitude computation as well as a procedure for the evaluation of uncertainties by the bootstrap technique. We also developed a user-friendly interface for parameter setup and graphical post-processing of the results. The improved code allows to locating epicenters in the sea or in uninhabited areas by minimizing the norm of the residuals of an attenuation equation. The same approach also per-mits, in the most favorable cases, the estimation of the source depth. By the geographical rendering of the bootstrap solutions we give a tool for characterizing the possible multiplicity of the seismic source of historical earthquakes.UnpublishedWien5.1. TTC - Banche dati e metodi macrosismiciope

A MATLAB procedure for the encoding of macroseismic effects and the objective estimation of seismic intensity by the Fuzzy sets method

Geophysical Research Abstracts, Vol. 11, EGU2009-5414, 2009 EGU General Assembly 2009 © Author(s) 2009 A MATLAB procedure for the encoding of macroseismic effects and the objective estimation of seismic intensity by the Fuzzy sets method. D. Tripone (1), P. Gasperini (2), G. Vannucci (3), and G. Ferrari (4) (1) INGV-Istituto Nazionale di Geofisica e Vulcanologia, Via Donato Creti, 12, I-40128, Bologna (Italy), ([email protected]), (2) Dipartimento di Fisica, Università di Bologna, Viale Berti-Pichat 8, I-40127 Bologna (Italy), ([email protected]), (3) INGV-Istituto Nazionale di Geofisica e Vulcanologia, Via Donato Creti, 12, I-40128, Bologna (Italy), ([email protected]), (4) INGV-Istituto Nazionale di Geofisica e Vulcanologia, Via Donato Creti, 12, I-40128, Bologna (Italy), ([email protected]) In previous works we developed a Fortran procedure for the encoding and the computer analysis of the macroseismic effects deduced from historical sources that allow the complete formalization of the process of seismic intensity assessment. The texts representing the macroseismic information are decomposed in 5 main syntactic elementary components by using alphanumeric codes. The database includes presently more than 33000 effects relative to 8 significant Italian earthquakes of the last two centuries that can be analyzed by multi-criteria decisionmaking algorithms to estimate objectively the seismic intensity at each locality. The complete procedure was now translated to MATLAB and was definitely improved by the inclusion of new tools for the encoding, the georeferencing and the checking of the data and of new Fuzzy algorithms for intensity determination. The output of the procedure is strictly integrated with the new version of “Boxer” code for the determination of seismic source parameters.PublishedWien5.1. TTC - Banche dati e metodi macrosismiciope

The Location and Sizing of Historical Earthquakes Using the Attenuation of Macroseismic Intensity with Distance

We herein describe new methods for computing the quantitative parameters of earthquakes using macroseismic data and the uncertainties associated with these parameters. The methods allow for the location of epicenters that are offshore or that have no intensities assigned to any points in the epicentral region by maximizing the likelihood function of an attenuation equation with observed intensity data. In the most favorable cases, such an approach also allows the estimation of the source depth and the local attenuation coefficients. We compute the parameter uncertainties in two ways: (1) using formal methods, such as the inversion of the Hessian of the loglikelihood function at its maximum, and (2) by using bootstrap simulations.We tested the performance of our methods by comparison with reliable instrumental hypocenters of onshore earthquakes, and found a reasonable agreement with the epicentral locations (within 10\u201315 km for more than 70% of cases) but not with the hypocentral depths, for which our results are generally underestimated by a factor of 2 or more and are poorly related to instrumental estimates. This finding indicates that the use of macroseismic depths in seismic hazard and seismotectonic investigations should be treated with caution. We nevertheless found good agreement (within 10\ub0\u201315\ub0) between the fault-trace orientations that were computed using the macroseismic data and the associated focal mechanisms of earthquakes with Mw !5:7. The surprising accuracy of the macroseismic orientations obtained using this method could in some cases allow the true fault to be inferred between the two conjugate planes of a given focal mechanism

The Location and Sizing of Historical Earthquakes Using the Attenuation of Macroseismic Intensity with Distance

We herein describe new methods for computing the quantitative parameters of earthquakes using macroseismic data and the uncertainties associated with these parameters. The methods allow for the location of epicenters that are offshore or that have no intensities assigned to any points in the epicentral region by maximizing the likelihood function of an attenuation equation with observed intensity data. In the most favorable cases, such an approach also allows the estimation of the source depth and the local attenuation coefficients. We compute the parameter uncertainties in two ways: (1) using formal methods, such as the inversion of the Hessian of the loglikelihood function at its maximum, and (2) by using bootstrap simulations.We tested the performance of our methods by comparison with reliable instrumental hypocenters of onshore earthquakes, and found a reasonable agreement with the epicentral locations (within 10–15 km for more than 70% of cases) but not with the hypocentral depths, for which our results are generally underestimated by a factor of 2 or more and are poorly related to instrumental estimates. This finding indicates that the use of macroseismic depths in seismic hazard and seismotectonic investigations should be treated with caution. We nevertheless found good agreement (within 10°–15°) between the fault-trace orientations that were computed using the macroseismic data and the associated focal mechanisms of earthquakes with Mw ≥5:7. The surprising accuracy of the macroseismic orientations obtained using this method could in some cases allow the true fault to be inferred between the two conjugate planes of a given focal mechanism

Estimating macroseismic intensity from documentary sources using Fuzzy Sets

Seismic intensity of historical earthquakes is usually assessed from documentary sources by the expert evaluation of the correspondence of reported effects with the descriptions of the adopted macroseismic scale. This process involves a number of subjective assumptions, not always explicitly stated, that sometimes may bring different experts to discrepant outcomes. We already proposed a decision making method, based on the fuzzy set theory and computer-aided procedures that can be successfully used to objectively assign macroseismic intensity. This approach is structured in three main steps: 1) the creation and computer coding of a dataset of effects for each locality, 2) the formulation of a set of rules to equate formally distinct macroseismic descriptions actually corresponding to the same effect 3) the application of a decisional algorithm to assign the intensity. The first two steps have now been improved and made friendlier, with respect to previous works, by the use of MS-Excel macros for data collection and management. We also applied and compared different decision algorithms and defuzzyfication methods using the data of some earthquakes of last century in Italy. Our analysis highlighted \u201cstrong\u201d effects well correlated with a specific intensity degree for all the analyzed earthquakes and other \u201cweak\u201d effects which association with the intensity degrees depends on the considered earthquake

Automated assessment of macroseismic intensity from written sources using the Fuzzy sets

We apply a computer-aided methodology to assess macroseismic intensity from the descriptions reported by documentary material available for eight Italian earth- quakes occurred around the beginning of the instrumental era. The procedure consists of three phases: (i) the identification of significant macroseismic effects on the sources and their archiving in a georeferenced database, (ii) the association between the effects and the degrees of the intensity scale by the comparison with traditional estimates made by macroseismic experts, (iii) the assessment of intensities using a multi-attribute decision- making algorithm based on the Fuzzy Sets logic. This work represents a substantial im- provement of our previous efforts as we completely redesigned the three phases of the procedure in the light of the experience of the last 10 years and analyzed six further Italian earthquakes so that our database now includes more than 19,000 encoded effects. Our formalized procedure allows to tracing all of the steps of intensity assessment process so that to identify discrepancies with respect to the expert evaluations that might be possibly due to mistakes or to the incomplete account of the available information. Hence, this approach may be useful for providing a systematic and reproducible intensity assessment as well as for supporting standard man-made assessments. The database of effects we have built could also be employed for testing the internal consistency of the macroseismic scale as well as for designing an improved macroseismic scale, based on consistent statistical criteria

Automated assessment of macroseismic intensity from written sources using the Fuzzy sets

We apply a computer-aided methodology to assess macroseismic intensity from the descriptions reported by documentary material available for eight Italian earth- quakes occurred around the beginning of the instrumental era. The procedure consists of three phases: (i) the identification of significant macroseismic effects on the sources and their archiving in a georeferenced database, (ii) the association between the effects and the degrees of the intensity scale by the comparison with traditional estimates made by macroseismic experts, (iii) the assessment of intensities using a multi-attribute decision- making algorithm based on the Fuzzy Sets logic. This work represents a substantial im- provement of our previous efforts as we completely redesigned the three phases of the procedure in the light of the experience of the last 10 years and analyzed six further Italian earthquakes so that our database now includes more than 19,000 encoded effects. Our formalized procedure allows to tracing all of the steps of intensity assessment process so that to identify discrepancies with respect to the expert evaluations that might be possibly due to mistakes or to the incomplete account of the available information. Hence, this approach may be useful for providing a systematic and reproducible intensity assessment as well as for supporting standard man-made assessments. The database of effects we have built could also be employed for testing the internal consistency of the macroseismic scale as well as for designing an improved macroseismic scale, based on consistent statistical criteria.Italian Presidenza del Consiglio dei Ministri–Dipartimento della Protezione Civile (DPC)Published2769–28033T. Pericolosità sismica e contributo alla definizione del rischioJCR Journalrestricte