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265 results on '"Wiemer, S"'

1. Hydromechanical Modeling of Fault Reactivation in the St. Gallen Deep Geothermal Project (Switzerland): Poroelasticity or Hydraulic Connection?

Author

Zbinden, D, Rinaldi, AP, Diehl, T, and Wiemer, S

Subjects
Meteorology & Atmospheric Sciences
Abstract

In 2013, fluid injection during the St. Gallen deep geothermal project, Switzerland, induced hundreds of seismic events, including a ML 3.5 earthquake on a fault hundreds of meters away from the well. Recent studies have suggested the direct pressure effect through permeable hydraulic connections and poroelastic effects as possible mechanisms for inducing seismicity on distant faults. In St. Gallen, operational, seismic, and earthquake data are available to investigate the underlying physical mechanisms using a numerical model. The results show that Coulomb stress changes at the fault can be 3 orders of magnitude greater when a hydraulic connection is present. Combining this with several field observations, we conclude that the direct pressure effect was more likely the predominant mechanism behind the seismicity induced in St. Gallen. The detection of hydraulic connections may be important for future projects as pressure can be driven far from the well and reactivate remote faults.

Published
2020

2. Simultaneous Dependence of the Earthquake‐Size Distribution on Faulting Style and Depth

Author

Petruccelli, A, Gasperini, P, Tormann, T, Schorlemmer, D, Rinaldi, AP, Vannucci, G, and Wiemer, S

Subjects
Earth Sciences, Geology, Geophysics, statistical seismology, seismotectonics, statistical modeling, earthquake forecasting, models evaluation, seismic hazard assessment, Meteorology & Atmospheric Sciences
Abstract

We analyze two high-quality Southern Californian earthquake catalogues, one with focal mechanisms, to statistically model and test for dependencies of the earthquake-size distribution, the b values, on both faulting style and depth. In our null hypothesis, b is assumed constant. We then develop and calibrate one model based only on faulting style, another based only on depth dependence and two models that assume a simultaneous dependence on both parameters. We develop a new maximum-likelihood estimator corrected for the degrees of freedom to assess models' performances. Our results show that all models significantly reject the null hypothesis. The best performing is the one that simultaneously takes account of depth and faulting style. Our results suggest that differential stress variations in the Earth's crust systematically influence b values and that this variability should be considered for contemporary seismic hazard studies.

Published
2019

3. Fault Stability Perturbation by Thermal Pressurization and Stress Transfer Around a Deep Geological Repository in a Clay Formation

Author

Urpi, L, Rinaldi, AP, Rutqvist, J, and Wiemer, S

Subjects
Earth Sciences, Geology, induced seismicity, thermal pressurization, clay, deep geological repository, fault reactivation, numerical finite element, Geochemistry, Geophysics
Abstract

The increase of temperature of a low-permeability, fluid-saturated media may trigger significant thermal pressurization, where the expansion of pore fluid cannot be accommodated by the thermal expansion of the pore space. With the aid of a coupled thermohydromechanical numerical simulator, we investigate the possible impact of thermal pressurization during the life of a deep geological repository (DGR) for high-level radioactive waste, characterized by the emplacement of radioactive material-filled canisters in a series of parallel tunnels, excavated in a low-permeability clay formation. We represent the fault as a planar structure embedded in a thermoporoelastic material and shear activation evaluated by a strain-softening Mohr-Coulomb failure criterion. The results show that stress changes caused by temperature and thermal pressurization of a rock mass around the emplacement tunnels may trigger a slip event on a fault plane in proximity of the geological disposal site: Rupture nucleates at depth, hundreds of meters below the DGR. Stress transfer plays a key role, while a direct hydraulic connection between the repository and the nucleation zone is not necessary in order to trigger rupture. A low stress ratio may favor the occurrence of slip up to a distance of 600 m of the fault from the outermost tunnel. These results highlight the need of investigating hydromechanical properties and local stress conditions at depth to characterize the geomechanical response of weak planes located in the surroundings of a high-level radioactive waste repository and to provide sufficient knowledge for the safe development of the DGR site.

Published
2019

4. The Effect of a Mainshock on the Size Distribution of the Aftershocks

Author

Gulia, L, Rinaldi, AP, Tormann, T, Vannucci, G, Enescu, B, and Wiemer, S

Subjects
Earth Sciences, Civil Engineering, Engineering, Geophysics, b value, aftershocks, stacking, Reid theory, differential stress, earthquake hazard forecasting, Meteorology & Atmospheric Sciences
Abstract

A systematic decay of the aftershock rate over time is one of the most fundamental empirical laws in Earth science. However, the equally fundamental effect of a mainshock on the size distribution of subsequent earthquakes has still not been quantified today and is therefore not used in earthquake hazard assessment. We apply a stacking approach to well-recorded earthquake sequences to extract this effect. Immediately after a mainshock, the mean size distribution of events, or b value, increases by 20–30%, considerably decreasing the chance of subsequent larger events. This increase is strongest in the immediate vicinity of the mainshock, decreasing rapidly with distance but only gradually over time. We present a model that explains these observations as a consequence of the stress changes in the surrounding area caused by the mainshocks slip. Our results have substantial implications for how seismic risk during earthquake sequences is assessed.

Published
2018

5. Current challenges in monitoring, discrimination, and management of induced seismicity related to underground industrial activities: A European perspective

Author

Grigoli, F, Cesca, S, Priolo, E, Rinaldi, AP, Clinton, JF, Stabile, TA, Dost, B, Fernandez, MG, Wiemer, S, and Dahm, T

Subjects
Mental Health, Meteorology & Atmospheric Sciences, Earth Sciences, Engineering, Physical Sciences
Abstract

Due to the deep socioeconomic implications, induced seismicity is a timely and increasingly relevant topic of interest for the general public. Cases of induced seismicity have a global distribution and involve a large number of industrial operations, with many documented cases from as far back to the beginning of the twentieth century. However, the sparse and fragmented documentation available makes it difficult to have a clear picture on our understanding of the physical phenomenon and consequently in our ability to mitigate the risk associated with induced seismicity. This review presents a unified and concise summary of the still open questions related to monitoring, discrimination, and management of induced seismicity in the European context and, when possible, provides potential answers. We further discuss selected critical European cases of induced seismicity, which led to the suspension or reduction of the related industrial activities.

Published
2017

6. On the physics-based processes behind production-induced seismicity in natural gas fields

Author

Zbinden, D, Rinaldi, AP, Urpi, L, and Wiemer, S

Subjects
production-induced seismicity, hydromechanical modeling, natural gas extraction, multiphase fluid flow, Poroelasticity, fault reactivation, Geochemistry, Geology, Geophysics
Abstract

Induced seismicity due to natural gas production is observed at different sites worldwide. Common understanding states that the pressure drop caused by gas production leads to compaction, which affects the stress field in the reservoir and the surrounding rock formations and hence reactivates preexisting faults and induces earthquakes. In this study, we show that the multiphase fluid flow involved in natural gas extraction activities should be included. We use a fully coupled fluid flow and geomechanics simulator, which accounts for stress-dependent permeability and linear poroelasticity, to better determine the conditions leading to fault reactivation. In our model setup, gas is produced from a porous reservoir, divided into two compartments that are offset by a normal fault. Results show that fluid flow plays a major role in pore pressure and stress evolution within the fault. Fault strength is significantly reduced due to fluid flow into the fault zone from the neighboring reservoir compartment and other formations. We also analyze scenarios for minimizing seismicity after a period of production, such as (i) well shut-in and (ii) gas reinjection. In the case of well shut-in, a highly stressed fault zone can still be reactivated several decades after production has ceased, although on average the shut-in results in a reduction in seismicity. In the case of gas reinjection, fault reactivation can be avoided if gas is injected directly into the compartment under depletion. However, gas reinjection into a neighboring compartment does not stop the fault from being reactivated.

Published
2017

10. The importance of earthquake interactions for injection-induced seismicity: Retrospective modeling of the Basel Enhanced Geothermal System

Author

Catalli, F, Rinaldi, AP, Gischig, V, Nespoli, M, and Wiemer, S

Subjects
Meteorology & Atmospheric Sciences
Abstract

We explore the role of earthquake interactions during an injection-induced seismic sequence. We propose a model, which considers both a transient pressure and static stress redistribution due to event interactions as triggering mechanisms. By calibrating the model against observations at the Enhanced Geothermal System of Basel, Switzerland, we are able to reproduce the time behavior of the seismicity rate. We observe that considering earthquake interactions in the modeling leads to a larger number of expected seismic events (24% more) if compared to a pressure-induced seismicity only. The increase of the number of events is particularly evident after the end of the injection. We conclude that implementing a model for estimating the static stress changes due to mutual event interactions increases significantly the understanding of the process and the behavior of induced seismicity.

Published
2016

12. Adaptively Smoothed Seismicity Earthquake Forecasts for Italy

Author

Werner, M. J., Helmstetter, A., Jackson, D. D., Kagan, Y. Y., and Wiemer, S.

Subjects
Physics - Geophysics, Physics - Data Analysis, Statistics and Probability
Abstract

We present a model for estimating the probabilities of future earthquakes of magnitudes m > 4.95 in Italy. The model, a slightly modified version of the one proposed for California by Helmstetter et al. (2007) and Werner et al. (2010), approximates seismicity by a spatially heterogeneous, temporally homogeneous Poisson point process. The temporal, spatial and magnitude dimensions are entirely decoupled. Magnitudes are independently and identically distributed according to a tapered Gutenberg-Richter magnitude distribution. We estimated the spatial distribution of future seismicity by smoothing the locations of past earthquakes listed in two Italian catalogs: a short instrumental catalog and a longer instrumental and historical catalog. The bandwidth of the adaptive spatial kernel is estimated by optimizing the predictive power of the kernel estimate of the spatial earthquake density in retrospective forecasts. When available and trustworthy, we used small earthquakes m>2.95 to illuminate active fault structures and likely future epicenters. By calibrating the model on two catalogs of different duration to create two forecasts, we intend to quantify the loss (or gain) of predictability incurred when only a short but recent data record is available. Both forecasts, scaled to five and ten years, were submitted to the Italian prospective forecasting experiment of the global Collaboratory for the Study of Earthquake Predictability (CSEP). An earlier forecast from the model was submitted by Helmstetter et al. (2007) to the Regional Earthquake Likelihood Model (RELM) experiment in California, and, with over half of the five-year experiment over, the forecast performs better than its competitors., Comment: revised manuscript. 22 pages, 3 figures, 2 tables

Published
2010
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13. Retrospective Evaluation of the Five-Year and Ten-Year CSEP-Italy Earthquake Forecasts

Author

Werner, M. J., Zechar, J. D., Marzocchi, W., and Wiemer, S.

Subjects
Physics - Geophysics, Physics - Data Analysis, Statistics and Probability
Abstract

On 1 August 2009, the global Collaboratory for the Study of Earthquake Predictability (CSEP) launched a prospective and comparative earthquake predictability experiment in Italy. The goal of the CSEP-Italy experiment is to test earthquake occurrence hypotheses that have been formalized as probabilistic earthquake forecasts over temporal scales that range from days to years. In the first round of forecast submissions, members of the CSEP-Italy Working Group presented eighteen five-year and ten-year earthquake forecasts to the European CSEP Testing Center at ETH Zurich. We considered the twelve time-independent earthquake forecasts among this set and evaluated them with respect to past seismicity data from two Italian earthquake catalogs. In this article, we present the results of tests that measure the consistency of the forecasts with the past observations. Besides being an evaluation of the submitted time-independent forecasts, this exercise provided insight into a number of important issues in predictability experiments with regard to the specification of the forecasts, the performance of the tests, and the trade-off between the robustness of results and experiment duration. We conclude with suggestions for the future design of earthquake predictability experiments., Comment: 43 pages, 8 figures, 4 tables

Published
2010

17. A workflow for rapid time-dependent estimates of earthquake-induced mass-movement likelihood and associated impacts in Switzerland

Author

Cauzzi, C., Knupfer, J., Wiemer, S., Danciu, L., Papadopoulos, A., and Kästli, P.

Abstract

Earthquake-induced mass movements are a substantial threat to mountainous areas in seismically active regions like the Valais, the most seismically hazardous region of Switzerland. We present a strategy to deliver rapid time-dependent predictions of mass-movement likelihoods in the Valais and their impacts on lifelines in near real-time during major earthquake sequences. We rely on the Swiss Seismic Hazard and ShakeMap frameworks and on the availability of a Swiss-specific empirical model for the prediction of seismically induced mass-movement likelihoods, and combine them with rapid earthquake shaking estimates based on short-term seismicity forecasts following a triggering seismic event. The obtained probabilities of mass-movement are spatially associated with exposed assets in the region to estimate the associated risk. This procedure can provide stakeholders with alarm levels and other decision-making tools based on risk-cost-benefit considerations for critical lifelines., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Published
2023
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22. Comment on 'Two Foreshock Sequences Post Gulia and Wiemer (2019)' by Kelian Dascher-Cousineau, Thorne Lay, and Emily E. Brodsky Comments and Replies

Author

Gulia, L, Wiemer, S, Gulia, L, and Wiemer, S

Subjects
foreshock traffic-light system, b-value, forecasting, Gulia and Wiemer
Abstract

Dascher-Cousineau et al. (2020) apply the so-called foreshock traffic-light system (FTLS) model proposed by Gulia and Wiemer (2019) to two earthquake sequences that occurred after the submission of the model: the 2019 Ridgecrest (M,,, 7.1) and the 2020 M,,, 6.4 Puerto Rico earthquakes. We show in this com-ment that the method applied by Kelian Dascher-Cousineau et al. (2020) deviates in at least six substantial and not well-doc-umented aspects from the original FTLS method. As a conse-quence, they used for example in the Ridgecrest case only 1% of the data available to estimate b-values and from a small sub-volume of the relevant mainshock fault. In the Puerto Rico case, we document here substantial issues with the homogeneity of the magnitude scale that in our assessment make a meaningful analysis of b-values impossible. We conclude that the evaluation by Dascher-Cousineau et al. (2020) is misrepresentative and a not a fair test of the FTLS hypothesis.

Published
2021

25. Fears of Visually Impaired Children.

Author

Wiemer, S. A. and Kratochwill, T. R.

Abstract

Examination of the number, content, and intensity of fears of 42 visually impaired children, aged 5-18, found more fears of potentially physically dangerous situations than of psychologically harmful ones and little difference between the number of mild and severe fears. Counselors' estimations of children's fears generally disagreed with the children's. (Author/DB)

Published
1991

30. Coda-Q in the 2.5-20 s period band from seismic noise : application to the greater Alpine area

Author

Soergel, D., Pedersen, H. A., Stehly, L., Margerin, L., Paul, A., Hetenyi, G., Abreu, R., Allegretti, I., Apoloner, M. T., Aubert, C., De Berc, M. B., Bokelmann, G., Brunel, D., Capello, M., Carman, M., Cavaliere, A., Cheze, J., Chiarabba, C., Clinton, J., Cougoulat, G., Crawford, W., Cristiano, L., Czifra, T., D'Alema, E., Danesi, S., Daniel, R., Dasovic, I., Deschamps, A., Dessa, J. X., Doubre, C., Egdorf, S., Fiket, T., Fischer, K., Friederich, W., Fuchs, F., Funke, S., Giardini, D., Govoni, A., Graczer, Z., Groschl, G., Heimers, S., Heit, B., Herak, D., Herak, M., Huber, J., Jaric, D., Jedlicka, P., Jia, Y., Jund, H., Kissling, E., Klingen, S., Klotz, B., Kolinsky, P., Korn, M., Kotek, J., Kuhne, L., Kuk, K., Loos, J., Malengros, D., Margheriti, L., Maron, C., Martin, X., Massa, M., Mazzarini, F., Meier, T., Metral, L., Molinari, I., Moretti, M., Munzarova, H., Nardi, A., Pahor, J., Pequegnat, C., Pesaresi, D., Piccinini, D., Piromallo, C., Plenefisch, T., Plomerova, J., Pondrelli, S., Prevolnik, S., Racine, R., Régnier, Marc, Reiss, M., Ritter, J., Rumpker, G., Salimbeni, S., Schulte-Kortnack, D., Scherer, W., Schippkus, S., Sipka, V., Spallarossa, D., Spieker, K., Stipcevic, J., Strollo, A., Sule, B., Szanyi, G., Szucs, E., Thomas, C., Tilmann, F., Ueding, S., Vallocchia, M., Vecsey, L., Voigt, R., Wassermann, J., Weber, Z., Weidle, C., Wesztergom, V., Weyland, G., Wiemer, S., Wolyniec, D., Zieke, T., Zivvic, M., and AlpArray Working Group

Subjects
Europe, surface waves and free oscillations, Coda waves, seismic attenuation, seismic noise, wave scattering and diffraction
Abstract

Coda-Q is used to estimate the attenuation and scattering properties of the Earth. So far focus has been on earthquake data at frequencies above 1 Hz, as the high noise level in the first and second microseismic peak, and possibly lower scattering coefficient, hinder stable measurements at lower frequencies. In this work, we measure and map coda-Q in the period bands 2.5-5 s, 5-10 s and 10-20 s in the greater Alpine region using noise cross-correlations between station pairs, based on data from permanent seismic stations and from the temporary AlpArray experiment. The observed coda-Q for short interstation distances is independent of azimuth so there is no indication of influence of the directivity of the incoming noise field on our measurements. In the 2.5-5 s and 5-10 s period bands, our measurements are self-consistent, and we observe stable geographic patterns of low and high coda-Q in the period bands 2.5-5 s and 5-10 s. In the period band 10-20 s, the dispersion of our measurements increases and geographic patterns become speculative. The coda-Q maps show that major features are observed with high resolution, with a very good geographical resolution of for example low coda-Q in the Po Plain. There is a sharp contrast between the Po Plain and the Alps and Apennines where coda-Q is high, with the exception a small area in the Swiss Alps which may be contaminated by the low coda-Q of the Po Plain. The coda of the correlations is too short to make independent measurements at different times within the coda, so we cannot distinguish between intrinsic and scattering Q. Measurements on more severely selected data sets and longer time-series result in identical geographical patterns but lower numerical values. Therefore, high coda-Q values may be overestimated, but the geographic distribution between high and low coda-Q areas is respected. Our results demonstrate that noise correlations are a promising tool for extending coda-Q measurements to frequencies lower than those analysed with earthquake data.

Published
2020

31. DESTRESS - soft stimulation treatments of geothermal reservoirs, Iceland

Author

Dahm, T., Zimmermann, G., Huenges, E., Heimann, S., Milkereit, C., Hjörleifsdóttir, V., Ásgeirsdóttir, R., Magnússon, R., Flovenz, Ó., Grigoli, F., and Wiemer, S.

Abstract

Near Reykjavik/Iceland, a "soft stimulation” geothermal experiment was performed in the frame of the DESTRESS project in 2019. The installed seismic stations consist of short period, and borehole stations in and around Geldinganes, NE of Reykjavik. The task of this network is the monitoring of the seismic events in the area around the stimulation site. The installation started in late 2018 with 6 short period stations (Reykjavik Energy). Since July 2019 additional seismic stations were integrated as a small scale array on the island Geldinganes and additional short period stations. A borehole geophone chain was installed with 17 short period 3-component geophones with a vertical spacing of 10 meter in the depth interval 1040m to 1200 m. Waveform data are available from the GEOFON data centre, under network code YG, and are embargoed until January 2025.

Published
2020

32. Abschätzung der Gefährdung durch Tsunamis in perialpinen Seen infolge Unterwasserhangrutschungen

Author

Strupler, M, Bacigaluppi, P, Kremer, K, Vetsch, D, Anselmetti, Flavio, Boes, R, and Wiemer, S

Subjects
550 Earth sciences & geology
Abstract

Historische Ereignisse haben gezeigt, dass Tsunamis nicht nur im marinen Bereich, sondern auch in Binnenseen auftreten können. Eine der Hauptursachen von See­ Tsunamis sind subaquatische Massenbewegungen. In diesem Beitrag präsentieren wir einen Arbeitsablauf zur Abschätzung der Gefährdung durch Tsunamis durch Unter­ wasserhangrutschungen in perialpinen Seen. Die Methodik besteht aus einer automa­ tischen Kartierung von potenziellen Unterwasserrutschungen und einer groben Ab­ schätzung der Wellenamplituden, die durch solche Rutschungen zu erwarten sind. Als Folge lässt sich die Wellenausbreitung und das Auflaufen der Welle an der Seeuferlinie für ausgewählte Fälle mit der GPU­optimierten Software «BASEMENT» simulieren. Der Arbeitsablauf generiert eine Übersicht über die Gefährdung durch Tsunamis der untersuchten Seen und erlaubt die Identifikation und Priorisierung von Unterwasser­ hängen und Seebecken, welche vertiefte, weiterführende Modellierungen benötigen.

Published
2020
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35. Increasing Earthquake Forecast Testability - CSEP Future Developments

Author

Schorlemmer, D., Hirata, N., Cotton, F., Gerstenberger, M., Marzocchi, W., Werner, M., Wiemer, S., Jordan, T., Beutin, T., Jackson, D., Maechling, P., Mak, S., Nanjo, K., Ogata, Y., Rhoades, D., Strader, A., Tsuruoka, H., Weatherill, G., Zhuang, J., and Savran, W.

Published
2019

42. International Peer-teaching: the LernKlinik Leipzig 'Erasmus-Week' for Incoming Erasmus Students

Author

Rotzoll, D, Wiemer, S, Zimmermann, A, Alex, P, Meixensberger, J, Rotzoll, D, Wiemer, S, Zimmermann, A, Alex, P, and Meixensberger, J

Abstract

Introduction: This project report describes the development, pilot phase, evaluation and implementation of a preparatory course week for incoming Erasmus medical students at the LernKlinik Leipzig, the Skills and Simulation Centre of the Medical Faculty, University of Leipzig.Project description: The aim of this project is to prepare Erasmus students for their year abroad using peer-assisted teaching as the method of choice. Major intended outcomes were support of language and clinical practical skill competency development, as well as enhancement of integration among international and German-speaking peer tutors. The methodological framework of Ross and Cameron was used in planning the Erasmus-Week. For planning the 2012 pilot project, a survey among Erasmus students of the academic year 2011/12 was performed. All succeeding cohorts were asked to participate in pre- and post-surveys which were analyzed quantitatively and qualitatively.Results: Between 2012 and 2017, n=173 European medical students spent their Erasmus year in Leipzig. Of these, n=148 (86%) participated in the Erasmus-Week. The country of origin of most Erasmus students was Rumania (20,3%). Among the most positively received aspects of the Erasmus-Week, the active use of German for medical purposes and the use of peer-teaching as the method of choice to learn and repeat basic medical examination skills were mentioned. Students emphasized their wish for being able to participate in further course offers.Conclusions: Offering a preparatory course week for incoming Erasmus students focusing on language and clinical practical skills training using peer-teaching as the method of choice may facilitate the integration of Erasmus students into their foreign medical curriculum. Further studies are underway to elucidate if these experiences influence later professional careers and choice of employment., Einleitung: Der vorgelegte Projektbericht beschreibt die Entwicklung, Pilotierung, Evaluation und Durchführung einer vorbereitenden Kurswoche für Erasmus-Studierende der Humanmedizin in der LernKlinik Leipzig, dem Skills- und Simulationszentrum der Medizinischen Fakultät der Universität Leipzig.Projektbeschreibung: Ziel des vorgestellten Lehrprojektes ist es, im geschützten Rahmen mittels Peer-teaching Methode Erasmus-Studierende auf ihr Auslandsjahr vorzubereiten. Das Augenmerk liegt dabei sowohl auf der sprachlichen als auch auf der klinisch-praktischen Ausbildung, aber auch auf der Integrationsförderung durch engen Kontakt mit deutschsprachigen studentischen Peer-Tutoren. Als methodischer Rahmen für die Planung der Erasmus-Woche diente die Zusammenstellung von Ross und Cameron . Zur Planung des Pilotprojektes 2012 wurde eine Befragung der Erasmus-Kohorte des Jahrgangs 2011/12 durchgeführt. Die nachfolgenden Jahrgänge wurden gebeten, an einer Prä-Post-Befragung teilzunehmen; die Freitextangaben der Prä- und Post-Befragungen wurden quantitativ und qualitativ ausgewertet.Ergebnisse: Insgesamt n=173 Erasmus-Studierende der Humanmedizin kamen im Zeitraum 2012-2017 nach Leipzig; von diesen nahmen n=148 (86%) an der Erasmus-Woche teil. Die meisten Erasmus-Studierenden kamen aus Rumänien (20,3%). Mit Abstand die häufigsten Nennungen zu den positiven Aspekten der Erasmus-Woche betrafen die aktive Auseinandersetzung mit der deutschen Fachsprache und die Wertschätzung des Peer-teaching Verfahrens, um grundlegende Untersuchungstechniken erlernen bzw. wiederholen zu können. Ein Ausbau und eine Intensivierung des Kursangebotes wurden gewünscht.Schlussfolgerungen: Die Durchführung einer vorbereitenden Kurswoche für Erasmus-Studierende mit Fokus auf Erwerb von sprachlichen und klinisch-praktischen Fertigkeiten im Peer-teaching Verfahren kann den Einstieg und die Integration Erasmus-Studierender in den Studienablauf erleichtern. Inwieweit diese Erfahrungen auch Einfluss auf die s

Published
2018

43. EPOS Seismology services and their users

Author

Haslinger, F., Dupont, A., Michelini, A., Rietbrock, A., Sleeman, R., Wiemer, S., Basili, R., Bossu, R., Cakti, E., Cotton, F., Crawford, W., Crowley, H., Danciu, L., Diaz, J., Garth, T., Locati, M., Luzi, L., Pitilakis, K., Roumelioti, Z., and Strollo, A.

Published
2017

44. Spatial distribution and energy release of nonvolcanic tremor at Parkfield, California

Author

Staudenmaier, N, Edwards, B, Tormann, T, Zechar, JD, and Wiemer, S

Abstract

Nonvolcanic tremors (NVTs) are observed in transition zones between freely slipping andlocked sections of faults and normally occur below the seismogenic zone. Based on NVT recordings in theParkfield region of the San Andreas Fault, we provide a novel approach to assess the energy release of theseevents and assign magnitudes (Me) that are compatible with size estimates of small earthquakes in the sameregion. To assess the energy magnitude of a detected tremor, we refine the estimate of its duration andperform a spectral analysis that accounts for local attenuation. For the 218 NVTs that we were able to process,we resolveMevalues in the range of 0.67 to 0.84. For events, which we could not process using the spectralanalysis technique, we propose a statistical model to estimateMevalues using observable characteristics,such as peak amplitude, spectral velocity at the source corner frequency, and duration. We furthermoreprovide seismic moment and moment magnitude estimates and calculate stress drops in a range of 3–10 kPa.As a result of our spectral analyses, wefind strong indications regarding the ongoing debate aboutpotential NVT location hypotheses: the Parkfield NVTs have a higher probability to be located in the proposedthree-dimensional cloud-like cluster than in any other suggested location distributio

Published
2016

45. Serious Asthma Events with Fluticasone plus Salmeterol versus Fluticasone Alone

Author

Stempel, Da, Raphiou, Ih, Kral, Km, Yeakey, Am, Emmett, Ah, Prazma, Cm, Buaron, Ks, Pascoe, Sj, Austri, Investigators, Altieri, Hh, Antuni, Jd, Bergna, Ma, Cuadrado, Ja, De Gennaro MS, Fazio Lizandrelo CL, Gattolin, G, Gosn, Am, Larrateguy, Ld, Marcipar, Am, Maspero, Jf, Medina, Iv, Perez Chada RD, Silva, D, Victorio, Cf, Bardin, Pg, Carroll, Pa, Clements, Bs, Dore, Nd, Robinson, Pd, Fitzgerald, Da, Robinson, Pj, Russo, Ma, Sajkov, D, Thomas, Ps, Upham, Jw, Forstner, B, Kaik, G, Koeberl, Gh, Studnicka, M, Wallner, G, Balthazar, Y, Bauler, A, Dupont, Lj, Martinot, Jb, Ninane, V, Peché, R, Pilette, C, Dimitrova, R, Dimova, D, Kissyova Ibrishimova, G, Loboshka Becheva, M, Machkovska, M, Madjarov, S, Mandazhieva Pepelanova, M, Naidenova, I, Noleva, K, Takovska, N, Terziev, C, Aggarwal, Nk, Chapman, Kr, Csanadi, Ma, Dhillon, R, Henein, S, Kelly, Aj, Lam, As, Liem, Jj, Lougheed, Md, Lowe, Dw, Rizvi, Q, van den Berg, L, Zidel, B, Barros Monge MJ, Calvo Gil MA, Castillo Hofer CR, Diaz Amor PV, Lezana Soya, V, Quilodran Silva CN, Bolivar Grimaldos, F, Solarte-Rodriguez, I, Butkovic-Tomljanovic, R, Hegedus-Jungvirth, M, Ivkovic-Jurekovic, I, Simunov-Karuza, G, Buresova, M, Bursova, J, Fratrik, J, Guttlerova, E, Hartman, P, Jirmanova, I, Kalina, P, Kolman, P, Kucera, M, Povysilova, L, Pravda, P, Svabkova, A, Zakova, L, Backer, V, Maltbaek, N, Johnsen, Cr, Aries, Sp, Babyesiza, A, Barth, D, Benedix, A, Berg, P, Bergtholdt, B, Bettig, U, Bindig, Hw, Botzen, U, Brehler, R, Breyer, Go, Bruckhaus-Walter, M, Dapper, T, Eckhard, Jg, Engelhard, R, Feldmeyer, F, Fissan, H, Franz, Kh, Frick, Bs, Funck, J, Gessner, Cm, Ginko, T, Grigat, Ce, Grimm-Sachs, V, Groth, G, Hampf, J, Hanf, G, Havasi-Jost, G, Heinz, Gu, Helm, K, Hoeltz, S, Hofmann, S, Jander, R, Jandl, M, Jasch-Hoppe, B, Jung, T, Junggeburth, Jj, Kardos, P, Knueppel, W, Koch, T, Kolorz, C, Korduan, M, Korth-Wiemann, B, Krezdorn, Hg, Kroker, A, Kruell, M, Kuehne, P, Lenk, U, Liefring, E, Merke, J, Micke, L, Mitlehner, W, Mueller, H, Naudts, If, Neumann, G, Oldenburg, W, Overlack, A, Panzer, F, Reinholz, N, Remppis, R, Riegel, P, Rueckert, P, Schaetzl, Rj, Schauer, U, Hamelmann, E, Schenkenberger, I, Schlegel, V, Scholz, G, Schroers, M, Schwittay, A, Sebert, M, Tyler, K, Soemantri, Pa, Stock, P, Stuchlik, G, Unland, M, von Mallinckrodt, C, Wachter, J, Weber, U, Weberling, F, Wehgartner-Winkler, S, Weimer, J, Wiemer, S, Winkelmann, Ej, Zeisler, Kh, Ziegner, A, Zimny, Hh, Andrasofszky, Z, Bartha, A, Farkas, M, Gömöri, K, Kis, S, Major, K, Mészáros, I, Mezei, M, Rakvacs, M, Szalai, Z, Szántó, J, Szentesi, M, Szolnoki, E, Valyon, E, Zibotics, H, Anwar, J, Arimah, C, Djajalaksana, S, Rai, Ib, Setijadi, Ar, Setyanto, Db, Susanti, F, Syafiuddin, T, Syamsi, Ln, Wijanarko, P, Yunus, F, Bonavia, M, Braga, M, Chetta, Aa, Cerveri, I, Luisetti, M, Crimi, N, Cutrera, R, De Rosa, M, Esposito, S, Foresi, A, Gammeri, E, Iemoli, E, Legnani, Dl, Michetti, G, Pastorello, Ea, Pesci, A, Pistolesi, M, Riva, E, Romano, A, Scichilone, N, Terracciano, L, Tripodi, S, Choi, I, Kim, C, Kim, Js, Kim, Wj, Koh, Yy, Kwon, Ss, Lee, Sh, Lee, S, Lee, Sk, Park, Cs, Cirule, I, Eglite, R, Petrova, I, Poga, M, Smiltena, I, Chomiciene, A, Davoliene, I, Griskeviciene, V, Naudziunas, A, Naudziunas, S, Rudzeviciene, O, Sitkauskiene, B, Urbonas, G, Vaicius, D, Valavicius, A, Valiulis, A, Vebriene, J, bin Abdul Aziz FA, Daud, M, Ismail, Ai, Tengku Saifudin TI, Md Kassim RM, Mohd Fadzli FB, Wan Mohamad WH, Aguilar Dominguez PE, Aguilar-Orozco, Ra, Garza-Salinas, S, Ramirez-Diaz, Sp, Sánchez Llamas, F, Soto-Ramos, M, Velarde-Mora, Hj, Aguirre Sosa, I, Cisneros, Am, Estrella Viladegut RA, Matsuno Fuchigami, A, Adiaz-Baui, Tt, Bernan, Ap, Onia, Af, Sandagon, Mj, S-Naval, S, Yu, Cy, Bartuzi, Z, Bielous-Wilk, A, Błażowski, Ł, Bożek, A, Brzostek, J, Chorostowska-Wynimko, J, Ciekalska, K, Ziora, D, Cieslicki, J, Emeryk, A, Folcik, K, Gałuszka-Bilińska, A, Gawlik, R, Giejlo, M, Harat, R, Hofman, T, Jahnz-Różyk, K, Jedrzejczak, M, Kachel, T, Kamiński, D, Kelm Warchol, A, Konieczny, Z, Kwasniewski, A, Leszczyński, W, Mincewicz, G, Niezgoda, K, Olszewska-Ziąber, A, Onasz-Manitius, M, Pawlukiewicz, M, Piotrowicz, P, Piotrowski, W, Pisarczyk-Bogacka, E, Piskorz, P, Prokop-Staszecka, A, Roslan, A, Słomka, A, Smalera, E, Stelmach, I, Swierczynska-Krepa, M, Szmidt, M, Tarnowska-Matusiak, M, Tłuczykont, B, Tyminska, K, Waszkuc-Golonko, J, Wojciechowska, I, Alexandrescu, Ds, Neamtu, Ml, Todea, D, Alekseeva, E, Aleksandrova, E, Asherova, I, Barbarash, Ol, Bugrova, O, Bukreeva, Eb, Chermenskiy, A, Chizhova, O, Demko, I, Evdokimova, A, Giorgadze, Ml, Grigoryev, S, Irkhina, I, Khurkhurova, Nv, Kondyurina, Eg, Kostin, Vi, Kudelya, L, Laleko, Sl, Lenskaya, L, Levashov, S, Logvinenko, N, Martynov, A, Mizernitski, Y, Nemtsov, B, Novozhenov, Vg, Pavlishchuk, S, Popova, Vv, Reshetko, Ov, Sherenkov, A, Shirinsky, Vs, Shpagina, L, Soloviev, Ki, Tkachev, A, Trofimov, Vi, Vertkin, Al, Vorobeva, E, Idrisova, E, Yakushin, S, Zadionchenko, V, Zhiglinskaya, O, Zykov, K, Dopudja Pantic, V, Nadaskic, R, Nestorovic, B, Skodric Trifunovic, V, Stojanovic, A, Vukcevic, M, Vujic, T, Mitic Milikic, M, Banovcin, P, Horvathova, H, Karako, P Sr, Plutinsky, J, Pribulova, E, Szarazova, M, Zlatos, A, Adams, L, Badat, A, Bassa, A, Breedt, J, Bruning, A, Ellis, Gc, Emanuel, S, Fouche, Lf, Fulat, Ma, Gani, M, Ismail, Ms, Jurgens, Jc, Nell, H, Nieuwoudt, G, Noor, F, Bolliger, Ct, Puterman, As, Siddique, N, Trokis, Js, Vahed, Ya, Van Der Berg BJ, Van der Linden, M, Van Zyl, L, Visser, Ss, Antépara Ercoreca, I, Arnedillo Muñoz, A, Barbe Illa, F, Barreiro López, B, Blanco Aparicio, M, Boada Valmaseda, A, Bosque García, M, Bustamante Ruiz, A, Carretero Anibarro, P, Del Campo Matias, F, Echave-Sustaet, Jm, Espinosa de los Monteros Garde MJ, Garcia Hernandez GM, López Viña, A, Lores Obradors, L, Luengo Planas MT, Monsó Molas, E, Navarro Dourdil, A, Nieto García AJ, Perpina Tordera, M, Picado Valles, C, Rodriguez Alvarez Mdel, M, Saura Vinuesa, A, Serra Batlles, J, Soler Sempere MJ, Toran Montserrat, P, Valdés Cuadrado LG, Villasante Fernandez-Montes, C, Cheng, Sl, Chern, Jh, Chiu, Mh, Chung, Cl, Lai, Rs, Lin, Ck, Liu, Yc, Wang, Cc, Wei, Yf, Amer, L, Berenfus, Vi, Besh, L, Duka, Kd, Fushtey, Im, Garmash, N, Dudnyk, O, Godlevska, O, Vlasenko, Ma, Hospodarskyy, I, Iashyna, L, Kaladze, M, Khvelos, Si, Kostromina, Vp, Krakhmalova, O, Kryuchko, T, Kulynych, Ov, Krasko, Mp, Levchenko, O, Litvinova, T, Panina, Ss, Pasiyeshvili, Lm, Prystupa, Ln, Romaniuk, Li, Sirenko, I, Synenko, Vi, Vynnychenko, Lb, Yatsyshyn, Ri, Zaitsev, I, Zhebel, V, Zubarenko, O, Arthur, Cp, Brown, V, Burhan, H, Chaudhuri, R, Collier, D, Barnes, Nc, Davies, Ej, Ellery, A, Kwok, S, Lenney, W, Nordstrom, M, Pandya, Hc, Parker, Iw, Rajakulasingam, K, Seddon, P, Sharma, R, Thomas, Ec, Wakeling, Ja, Abalos-Galito, M, Abboy, C, Abreu, E, Ackerman, If, Acosta, Ia, Adaoag, Aa, Ahmed, M, Ali, Mi, Allen, Dr, Allen GG Jr, Diogo, Jj, Allison, Dc, Alwine, Lk, Apaliski, Sj, Arastu, Rs, Arora, Cm, Auerbach, D, Azzam, Sj, Badar FL 3rd, Baker, Jw, Barasch, Jp, Barber, Ma, Bardinas-Rodriguez, R, Barreiro, Tj, Baumbach, Rr, Baur, Ce, Baxter, Bs, Beach, Jl, Beasley, Rl, Beavins, Je, Beliveau, Wj, Benbow, Mj, Bennett, Nl, Bennett, Rl, Bernal, H, Bernstein, Di, Blaiss, Ms, Blumenthal, Kw, Boas, Sr, Borders, Jl, Boscia, Ja, Boulware, Wn, Bowling, Bt, Brabec, Ba, Bramlet, Dg, Figueroa, Dp, Brautigam, Df, Brownell, Jm, Bruce, Tr, Call, Rs, Campbell, Ca, Canaan, Ya, Cannon, Df, Carpio, Jm, Cathcart, Ws, Cevallos, Jp, Chauhan, Av, Chuang, Rb, Chevalier, D, Christensen, J, Christensen, Ta, Christina, Mo, Chrzanowski, Rr, Civitarese, Fa, Clark, Jp, Clifford, Dp, Lapidus, Rj, Coggi, Ja, Lenz, Jj, Cohen, Kr, Collins, Bg, Collins, H, Comellas, A, Condit, J, Cordasco EM Jr, Corder, Cn, Covar, Ra, Coverston, Kd, Croce, Sa, Cruz, H, Curtis, Ct, Daftary, Pk, Dalan, D, Dalawari, Sp, Daly, Wc, Davis, Kc, Dawes, Kw, Decotiis, Ba, Deluca, Rf, Desantis, Dm, De Valle OL, Diaz, Jl, Diaz, Jd, Dice, Jp, Elizalde, A, Hosler, Mr, Dixon, C, Dobkin, La, Dobrusin, Rs, Dransfield, Mt, Ebbeling, Wl, Edwards, Jd, Elacion, Jm, Elkayam, D, Ellison, Wt, Elsen, Jr, Engel, Lr, Ensz, Dj, Ericksen, Cl, Ervin, Je, Fang, C, Abrahamian, F, Farrah, Vb, Field, Jd, Fishman, Hj, Florea, R, Nayyar, S, Focil, A, Focauld, F, Franco MA Jr, Frandsen, Br, Ganti, K, Garcia, Fl, Lee, Wm, Garscadden, Ag, Gatti, Ea, Gellady, Am, George, Ar, Gibbon, Gw, Gleason, Gp, Goldberg, P, Goldstein, Mf, Gonzalez, Ge, Gower, Rg, Grande, Ja, Gregory, D, Grubb, Sd, Guthrie, Rp, Haas, Ta, Haft, Ks, Hajal, R, Hammond, Gd, Hansel, Nn, Hansen, Vr, Harris, Af, Hartman, An, Harvey, Rr, Hazan-Steinberg, S, Headley, Dm, Heigerick, Gc, Heller, Bn, Hendrix, El, Herrod, Jn, Hewitt, Mj, Hines, Rl, Hirdt, Ap, Hirschfield, Ja, Hoffman, Ks, Hogan, Ad, Howland, Wc, Hsu, Cc, Hsu, Fj, Hubbard, Wm, Hudson, Jd, Huffman, C, Hussain, M, Ioachimescu, Oc, Ismail, Ym, Jaffrani, Na, Jiang, N, Jones, Sw, Jordan, Rs, Joshi, Ke, Kaashmiri, Mw, Kalafer, M, Kamdar, Ba, Kanuga, Jg, Kao, Nl, Karetzky, M, Katsetos, Jc, Kay, Js, Kimmel, Ma, Kimura, Sh, Kingsley, Jk, Mahmood, Sm, Subich, Dc, Kirstein, Jl, Kleerup, Ec, Klein, Rm, Koh, Dw, Kohli, N, Koura, Fa, Kovacs, Sp, Kratzer, J, Kreit, Ci, Kreutter, Fm, Kubicki, Tm, Labuda, Jm, Latorre, Aj, Lara, Mm, Lechin, Ae, Lee, Jj, Lee, Md, Lentnek, Al, Lesh, Kw, Levins, Pf, Anspach, Rb, Levinsky, Dm, Lillestol, Mj, Lim, H, Livezey, Md, Lloyd-Turney, Cw, Lockey, Rf, Long, Ra, Lynch, Mj, Macgillivray, Bk, Mahadevan, Kp, Makam, Sk, Maloney, Mj, Mapel, D, Margolis, Bd, Margulies, J, Martin, Ef, Martin, Ee, Mascolo, M, Mataria, H, Sunbuli, M, Mathur, Rn, Mattar, Pn, Maynard, Km, Maynard, N, Mccormick, B, Mcelya, M, Mcevoy, Ce, Mckenzie, Wc, Medwedeff, Le, Mehta, Kd, Melamed, Ir, Meli, Jv, Merrick, Bh, Meyers, Pj, Miller, Bt, Minton, Sm, Miranda, Fg, Mohar, De, Montenegro, Ch, Morris, Fa, Morrison, Bs, Moss, Mh, Munoz, F, Naini, Gr, Nakamura, Ct, Naseeruddin, S, Nassim, C, Navazo, Lj, Nissim, Je, Norman, D, Oberoi, Ms, O'Connor, Tm, Offenberger, J, Orr, Rr, Osea, Ea, Paine, Wj, Rasmussen, Nl, Palatnik, M, Pangtay, D, Panuto, Ja, Patel, M, Perera, Ms, Perez, A, Peters PH Jr, Pimentel SM Jr, Pluto, Tm, Pollock, Mt, Posner, Ls, Pritchard, Jc, Pudi, Kk, Puig, Cm, Qaqundah, Py, Radbill, Mk, Rahman, St, Raikhel, M, Raissy, Hh, Ramstad, Ds, Ranasinghe, Es, Rangel, Os, Rapo, Se, Raschal, Sp, Reddy, Dg, Rehman, Sm, Reyes, Sr, Rhodes, Rb, Riffer, E, Rihal, Ps, Riley ED 4th, Rodriguez, Dh, Rogers, Cm, Rohlf, Jl, Romeu, H, Roney, Cw, Ronsick, So, Rosen, Jb, Rowe, Ms, Ruoff, Ge, Ryan, Eh, Saff, Rh, Saini, N, Anand, S, Balakrishnan, K, Samuels, Bs, Samuelson, Rj, Saniuk, Rj, Sargeant, Wo, Saunders, Mk, Saway, W, Scarupa, Md, White, Mv, Schear, Mj, Schwarz, Cm, Scott, Rb, Segall, N, Seibert, Af, Seidmeyer, V, Seidner, Mr, Seifer, Fd, Serje, J, Shah, Ms, Shah, Sb, Shapero, Pa, Shearer, Sd, Sheikh, Sq, Shepherd, Ts, Sher, Er, Sher, Ld, Short, Bh, Silas, Pe, Alvey, Jc, Silverfield, Jc, Simon, Sj, Sitar, S, Skoner, Dp, Smallow, Sa, Smart, Ba, Smith, Ca, Smith, Ke, Smith, Sk, Snyders, Gc, Soong, W, Soufer, J, Spangenthal, S, Stahlman, Je, Steele, Lg, Stegemoller, Rk, Stocks, J, Storms, Ww, Suen, J, Surowitz, Rz, Swauger, Jr, Taber, La, Tan, Ae, Pratt, Se, Tanus, T, Tarpay, Mm, Tarshis, Ga, Tenney, Jw, Tilghman, Kg, Trevino, Me, Troyan, Be, Twiddy, Sk, Updegrove, Jd, Urval, Kr, Uusinarkaus, Kt, Vaela, R, Van Cleeff, M, Varano, S, Vo, Qd, Wainz, Rj, Wald, Ja, Wall, Sj, Wasserman, Rl, Weinstein, Dl, Welker, Ja, Wellmon, B 2nd, Wells, T, Wenocur, Hs, Williams, Dl, Williams, Sl, Win, Ph, Wingo, Td, Wisman PP Jr, Wyszomierski, Da, Yamada, Hm, Yarows, S, Yunger TM Jr, Ziering, Rw., the AUSTRI Investigators, Stempel, D., Raphiou, I., Kral, K., Yeakey, A., Emmett, A., Prazma, C., Buaron, K., and Pascoe, S. Scichilone N tra i collaboratori

Subjects
Male, asthma, serious events, fluticasone, salmeterol, AUSTRI, Exacerbation, Intention to Treat Analysi, INHALED CORTICOSTEROIDS, Severity of Illness Index, law.invention, 0302 clinical medicine, Randomized controlled trial, law, immune system diseases, Ús terapèutic, Broncodilatadors, 030212 general & internal medicine, Child, Fluticasone, RISK, ACTING BETA-AGONISTS, EXACERBATIONS, METAANALYSIS, MORTALITY, SAFETY, DEATH, FDA, Medicine (all), Hazard ratio, General Medicine, Bronchodilator agents, Middle Aged, Fluticasone-Salmeterol Drug Combination, Bronchodilator Agents, Intention to Treat Analysis, Anesthesia, Female, Salmeterol, medicine.drug, Human, Adult, medicine.medical_specialty, Adolescent, Settore MED/10 - Malattie Dell'Apparato Respiratorio, Fluticasone propionate, 03 medical and health sciences, Double-Blind Method, Internal medicine, Administration, Inhalation, medicine, Humans, Asma, Bronchodilator Agent, Asthma, Aged, Proportional Hazards Models, business.industry, Therapeutic use, medicine.disease, respiratory tract diseases, 030228 respiratory system, Fluticasone Propionate, Salmeterol Xinafoate Drug Combination, Proportional Hazards Model, business
Abstract

BACKGROUND The safe and appropriate use of long-acting beta-agonists (LABAs) for the treatment of asthma has been widely debated. In two large clinical trials, investigators found a potential risk of serious asthma-related events associated with LABAs. This study was designed to evaluate the risk of administering the LABA salmeterol in combination with an inhaled glucocorticoid, fluticasone propionate. METHODS In this multicenter, randomized, double-blind trial, adolescent and adult patients (age, ≥12 years) with persistent asthma were assigned to receive either fluticasone with salmeterol or fluticasone alone for 26 weeks. All the patients had a history of a severe asthma exacerbation in the year before randomization but not during the previous month. Patients were excluded from the trial if they had a history of lifethreatening or unstable asthma. The primary safety end point was the first serious asthma-related event (death, endotracheal intubation, or hospitalization). Noninferiority of fluticasone–salmeterol to fluticasone alone was defined as an upper boundary of the 95% confidence interval for the risk of the primary safety end point of less than 2.0. The efficacy end point was the first severe asthma exacerbation. RESULTS Of 11,679 patients who were enrolled, 67 had 74 serious asthma-related events, with 36 events in 34 patients in the fluticasone–salmeterol group and 38 events in 33 patients in the fluticasone-only group. The hazard ratio for a serious asthmarelated event in the fluticasone–salmeterol group was 1.03 (95% confidence interval [CI], 0.64 to 1.66), and noninferiority was achieved (P = 0.003). There were no asthma-related deaths; 2 patients in the fluticasone-only group underwent asthmarelated intubation. The risk of a severe asthma exacerbation was 21% lower in the fluticasone–salmeterol group than in the fluticasone-only group (hazard ratio, 0.79; 95% CI, 0.70 to 0.89), with at least one severe asthma exacerbation occurring in 480 of 5834 patients (8%) in the fluticasone–salmeterol group, as compared with 597 of 5845 patients (10%) in the fluticasone-only group (P

Published
2016

50. Rupture Process of the Mw 3.3 Earthquake in the St. Gallen 2013 Geothermal Reservoir, Switzerland.

Author

Király‐Proag, E., Satriano, C., Bernard, P., and Wiemer, S.

Subjects
EARTHQUAKE aftershocks, GREEN'S functions, RESERVOIRS, EARTHQUAKES, INDUCED seismicity
Abstract

We analyze slip distribution and rupture kinematics of a Mw3.3 induced event that occurred in the St. Gallen geothermal reservoir (NE Switzerland) in 2013. We carry out a two‐step procedure: (1) path effects are deconvolved from the seismograms using an empirical Green's function, resulting in relative source time functions at all seismic stations; (2) the relative source time functions are back‐projected to the corresponding isochrones on the fault plane. Results reveal that the mainshock rupture propagates toward NNE from the hypocenter with an average velocity of 2,000 m/s. Spatiotemporal organization of foreshocks and aftershocks shows that the mainshock broke a previously less active portion of the fault and suggests that the aftershock sequence could be mainly driven by stress transfer. Applying this method in an operational environment could enable fast retrieval of seismic slip, allowing assessment of fault asperities and structures involved in the reservoir creation process. Plain Language Summary: In most models and analyses, small earthquakes (i.e., magnitude less than 4) are considered either point sources or homogeneous "penny‐shaped" surfaces. While these assumptions may be valid, details of earthquake ruptures are more complex. Here we study a magnitude 3 induced earthquake that occurred in the St. Gallen geothermal reservoir (NE Switzerland) in 2013. We image the earthquake rupture by refocusing on the fault the seismic energy recorded at six sensors located within 15 km from the source. Our results show that a detailed description of the rupture process of such a small earthquake can indeed be obtained: The rupture propagates from the hypocenter in NNE direction for 150 m, with an average velocity of 2 km/s, breaking into a less active portion of the fault, where no earthquake was previously recorded. The proposed method could be routinely applied during geothermal reservoir operations to allow rapid assessment of fault structures involved in the reservoir creation process. Key Points: Our approach reveals rupture complexity for a magnitude 3.3 fluid‐induced earthquake at 100‐m scaleThe rupture propagated toward NNE, breaking into a previously less active portion of the faultEarly aftershocks distribute around the main slip area, suggesting a stress transfer mechanism [ABSTRACT FROM AUTHOR]

Published
2019
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