Papers by Wolfgang Lenhardt
Der Einfluss von Erdbeben auf den Bergbau
Der Schau- und Lehrstollen Arzberg/Steiermark: Beispiel für eine intelligente Nachnutzung eines Altbergbaus
BHM Berg- und Hüttenmännische Monatshefte, 2016
Assessing the completeness of historical earthquake records in Austria and surrounding Central Europe
Completeness of earthquake catalogues is a necessary condition for seismic hazard assessment sinc... more Completeness of earthquake catalogues is a necessary condition for seismic hazard assessment since they are the base for the determination of a and b values of the Gutenberg-Richter relation. A new composite catalogue for Austria has been created based on data from four different catalogues of earthquakes in Austria (ZAMG, 2009; ACORN, 2004; Van Gils & Leydecker, 1991; Shebalin et al., 1998) including for the first time also data from surrounding regions such as the Vienna Basin outside Austria and a buffer region 100km outside the boundary of the Austria and Vienna basin. The used earthquake catalogues cover different record length with a first entry in 1048 AD. A reliable estimate of the a and b parameters of the Gutenberg-Richter Relation from this newly compiled dataset can be only given, if the new catalogue is checked for completeness. We determined the completeness intensity (Ic) and the completeness periods for the composite catalogue following the method described by Stepp (1972). This method supposes that the earthquake occurrences are Poisson-distributed and investigates (i) the minimum observation interval required to reach reliable estimates of mean recurrence periods, (ii) the time interval for which the catalogues may be regarded complete. Both intervals are functions of the intensity class. Ic is the smallest intensity above which every earthquake was recorded for a given time interval. The completeness period is the time interval in which the catalogue is complete for a given intensity range. As most of the catalogue's records are pre-instrumental data, this completeness check was performed on intensity data avoiding ambiguities arising from intensity-magnitude conversion. In a second step, we repeated the completeness check, but this time based on magnitudes in order to determine the influences of various magnitude conversions. For pre-instrumental events, we converted intensities into magnitudes using published intensity-magnitude conversion formula for each country. In order to get the completeness periods for various magnitude ranges, the combined catalogue as well as each subcatalogue have been analyzed following the method of Stepp (1972). We can show that the new composite catalogue fulfills the critical minimum observation period for all intensity classes except IX and higher. A stable estimate of mean recurrence period of intensity IV is 80 years of homogeneous observations from 1900 to 1980 and for intensity V, the observation period is 120 years. A stable estimate of mean recurrence period for intensity VI is about 115 years and for intensity vii is 30 years. The homogeneous interval for maximum intensity VIII is 200 years. Maximum intensity IX earthquakes are not completely definitive for whole 962 years period. In addition, the analysis of each subcatalogue leads to similar results, except the ACORN catalogue. Therefore, the newly complied catalogue for Austria and surrounding areas is a suitable data base for seismic hazard assessment in Austria. References: ACORN, 2004, Catalogue of Earthquakes in the Region of the Alps - Western Carpathians - Bohemian Massif for the period from 1267 to 2004, Computer File, Vienna (Central Institute for Meteorology and Geodynamics, Department of Geophysics) - Brno (Institute of Physics of the Earth, University Brno). Van Gils, J.M. and G. Leydecker (1991): Catalogue of European earthquakes with intensities higher than 4. -- Commission of the European Communities - nuclear science and technology. 353 pp., 14 fig., 1 tab.- ISBN 92-826-2506-0, Catalogue number: CD-NA-13406-EN-C. Brussels - Luxembourg 1991. Shebalin, N. V., Leydecker, G., et al. (1998): Earthquake Catalogue for Central and Southeastern Europe 342 BC - 1990 AD. -- European Commission, Report No. ETNU CT 93 - 0087, Brussels. Stepp, J.C., 1972. Analysis of completeness of the earthquake sample in the Puget Sound area and its effect on statistical estimates of earthquake hazard. Proc. of the 1st Int. Conf. on Microzonazion, Seattle, vol. 2, pp. 897-910. ZAMG, 2009. Earthquake catalogue of felt earthquakes 1201 - 2009 A.D. (Austria). Computer File. Central Institute of Meteorology and Geodynamics (ZAMG), Vienna Austria.
Focal-depth distributions in the Austrian Eastern Alps based on macroseismic data
Austrian Journal of Earth Sciences, 2007
From macroseismic data, focal depths of several parts in Austria are estimated and discussed.
Geologica Carpathica
The seismicity of the geological complexes of the northern part of the Eastern Alps, the Western ... more The seismicity of the geological complexes of the northern part of the Eastern Alps, the Western Carpathians and the Bohemian Massif is investigated by means of new seismic stations and a review of earthquake catalogues available. Eleven earthquake catalogues are evaluated and checked for multiple entries, fake earthquakes and mis-takes. The final data set of earthquakes covers the time span from 1267 to 2004 and comprises 1968 earthquakes in total. The resulting epicentral map provides a very detailed idea of the seismicity of this region. An attempt at a seismo-tectonic interpretation of earthquakes based on the geological overview of the region is presented. Gravity and airborne magnetometry data in addition to seismic events are collected and cross-border maps are compiled and analysed in order to determine the spatial extent of these geological structures. The Linsser filtering technique is used to trace faults at two depth horizons – 4 and 8km. Correlation between the epicentr...
Assessing the completeness of historical earthquake records in Austria and surrounding Central Europe
Completeness of earthquake catalogues is a necessary condition for seismic hazard assessment sinc... more Completeness of earthquake catalogues is a necessary condition for seismic hazard assessment since they are the base for the determination of a and b values of the Gutenberg-Richter relation. A new composite catalogue for Austria has been created based on data from four different catalogues of earthquakes in Austria (ZAMG, 2009; ACORN, 2004; Van Gils & Leydecker, 1991; Shebalin et
Erdbeben in Niederösterreich von 1000 bis 2009 n. Chr
Zusammenfassung Niederösterreich zählt zu jenen Bundesländern in Österreich die wiederholt von Er... more Zusammenfassung Niederösterreich zählt zu jenen Bundesländern in Österreich die wiederholt von Erdbeben betroffen sind. Insbesondere das Wiener Becken zählt, neben dem Tiroler Inntal, dem Mur-Mürztal in der Steiermark und dem südlichen Kärnten zu den am häufigsten von Erdbeben betroffenen Regionen Österreichs. Im 20. Jahrhundert haben sich allein im Wiener Becken nicht weniger als 345 fühlbare Erdbeben und 17 Schadensbeben ereignet. Zum Thema der Seismizität in Niederösterreich (suess, 1874; drimmel, 1980, 1981b; eisinger et al., 1992) und der geologischen Situation des von Erdbeben am meisten betroffenen Gebietes in Niederösterreich, dem Wiener Becken (Wessely, 1988), wurden in der Vergangenheit mehrere Untersuchungen durchgeführt. Um den Stand der Wissenschaft bezüglich der Seismizität Niederösterreichs zu gewährleisten, wurde im Rahmen zweier Projekte im Auftrag der Niederös- terreichischen Landesregierung, sowohl die historische (hammerl, 2004, 2005, 2006) als auch die rezente E...
A review of the 1590 earthquake in Lower Austria and its effects on Vienna
The project "Historical Earthquakes in Lower Austria" serves to complete the Austrian E... more The project "Historical Earthquakes in Lower Austria" serves to complete the Austrian Earthquake Catalogue to gain a better image in terms of seismic hazard. The project aims at the investigation of: - so far unknown earthquakes, - fake quakes, and - the correction of false catalogue entries. To improve the seismic hazard assessment in Lower Austria the project focuses mainly on the research of gaps and the restudy of the most important historical earthquakes in the area like the damaging Neulengbach earthquake of 16 September 1590 with the epicentral intensity Io=9 EMS (Hammerl, Ch., 2007. „Die khirchen dermassen zerschmetert und zerlittert, das man nit darein darf..." - Historische Erdbebenforschung in Niederösterreich. Studien und Forschungen aus dem Niederösterreichischen Institut für Landeskunde, 46, 21-44). The results of the project among others - the translation, the interpretation and the documentation of the original sources, the intensity estimation for eac...
The Conrad Observatory Research Facility
The Conrad Observatory in Austria belongs to the group of most modern geophysical observatories w... more The Conrad Observatory in Austria belongs to the group of most modern geophysical observatories worldwide. The observatory is situated 55 km SW of Vienna in the Eastern Alps. Since 2002 - when the observatory was officially opened - several research tasks, projects, training courses and workshops were carried out at this venue. The site is also magnetically very quiet -
Abschätzung der Erdbebengefährdung für die D-A-CH-Staaten - Deutschland, Österreich, Schweiz
Bautechnik, 1998
ABSTRACT
Fractal Concepts and their Application to Earthquakes in Austria
Aspects of Tectonic Faulting, 2000
Earthquakes – From Cause to Effect
Geomechanik und Tunnelbau, 2008
BHM Berg- und Hüttenmännische Monatshefte, 2009
It is well known, that mining activity can result in seismic events. On the other hand, tectonic ... more It is well known, that mining activity can result in seismic events. On the other hand, tectonic -or natural -earthquakes are able to cause distress to mine openings and open cast mines which may lead to instable situations. It will be shown, that natural earthquakes have a limited impact on underground mining operations but should not be neglected at surface operations and tunnel openings.
Schadensbeben in Österreich - Beurteilung bestehender Bauwerke
Bautechnik, 2005
ABSTRACT Bauwerke. die entsprechend den letztgültigen Normen bemessen werden, sind heute bereits ... more ABSTRACT Bauwerke. die entsprechend den letztgültigen Normen bemessen werden, sind heute bereits relativ erdbebensicher. Ein Problem stellen jedoch älteren Bauwerke dar, da früher fallweise nur eine unzureichende oder keine Berücksichtigung des Lastfalls Erdbeben erfolgte. Überdies wurden in den letzten Jahren neue Erdbebengefährdungskarten mit vergrößerten, seismisch aktiven Zonen erstellt. Zusätzlich besteht das Problem, daß durch das relativ seltene Auftreten von Erdbeben in Österreich kein ausgeprägtes Risikobewußtsein besteht und daher die Erdbebensicherheit im Bauwesen nur als untergeordnetes Thema betrachtet wird. Grundsätzlich ist es weder wirtschaftlich noch technisch machbar, die Erdbebensicherheit jedes bestehenden Bauwerks gemäß der neuen Normengeneration zu überprüfen und zu erhöhen. Der Ansatzpunkt besteht jedoch in der Untersuchung und Ertüchtigung von wichtigen Bauwerken, die vor allem nach einem Erdbeben funktionstüchtig bleiben müssen. Dazu kommt eine innovative Methode aus Kombination von dynamischen Messungen und FE-Berechnungen zur Anwendung. In diesem Beitrag erfolgt neben der exemplarischen Darstellung dieses modernen Beurteilungsverfahrens eine Zusammenstellung der Schadensbeben in Österreich innerhalb der letzten 10 Jahre.Earthquakes in Austria – evaluation of existing buildings.Structures which are designed according to recent codes and guidelines are comparatively earthquake resistant nowadays. However existing older structures are still a problem, because sometimes an insufficient or no consideration of the load case earthquake was performed earlier. Moreover new seismic hazard maps were issued during the last years, which are reporting increased seismic areas. In addition it must be mentioned, that due to the rarely appearance of earthquakes in Austria no strongly developed risk awareness is available. Therefore the earthquake safety in civil engineering only is considered as minor problem. Of course it is neither economic nor feasible from technical point of view, to investigate and increase the earthquake safety of all existing structures according to the recent seismic codes. The clear starting point is the investigation and rehabilitation of important buildings, which must ensure their functionality in particular after an earthquake. Therefore an innovative method was developed, combining dynamic in-situ measurements and finite element calculations. Besides the exemplary description of this modern assessment method a summary of design earthquakes from the last 10 in Austria years is presented in this paper.
Can deep seated gravitational slope deformations be activated by regional tectonic strain: First insights from displacement measurements in caves from the Eastern Alps
Geomorphology, 2016
Applying Spectral Ratio Techniques to Estimate Station Site Responses
Site effects in seismic data acquisition
ABSTRACT
Since 2002 the OGS (Istituto Nazionale di Oceanografia e di Geofisica Sperimentale) in Udine (Ita... more Since 2002 the OGS (Istituto Nazionale di Oceanografia e di Geofisica Sperimentale) in Udine (Italy), the Zentralanstalt für Meteorologie und Geodynamik (ZAMG) in Vienna (Austria), and the Agencija Republike Slovenije za Okolje (ARSO) in Ljubljana (Slovenia) are using the Antelope software suite as the main tool for collecting, analyzing, archiving and exchanging seismic data in real time, initially in the framework of the EU Interreg IIIa Italia-Austria project "Trans-national seismological networks in the South-Eastern Alps" . The data exchange has proved to be effective and very useful in case of seismic events near the borders between Italy, Austria and Slovenia, where the poor single national seismic networks coverage precluded a correct localization, while the usage of common data from the integrated networks improves considerably the overall reliability of real time seismic monitoring of the area. At the moment the data exchange between the seismic data centers relies on internet: this however is not an ideal condition for civil protection purposes, since internet reliability is poor. For this reason in 2012 the Protezione Civile della Provincia Autonoma di Bolzano in Bolzano (Italy) joined OGS, ZAMG and ARSO in the Interreg IV Italia-Austria project "SeismoSAT" (Progetto SeismoSAT, 2012) aimed in connecting the seismic data centers in real time via satellite. As here illustrated, the general technical schema of the project has been approved, data bandwidths and monthly volumes required have been quantified, the common satellite provider has been selected, the hardware has been purchased and installed, and the all SeismoSAT project is in testing phase.
Since 2002, OGS (Istituto Nazionale di Oceanografia e di Geofisica Sperimentale) in Italy, the Ag... more Since 2002, OGS (Istituto Nazionale di Oceanografia e di Geofisica Sperimentale) in Italy, the Agencija Republike Slovenije za Okolje (ARSO) in Slovenia, and the Zentralanstalt für Meteorologie und Geodynamik (ZAMG) in Austria are exchanging seismic data in real time. The data exchange is very effective for seismic events at the borders between Italy, Slovenia and Austria, where the poor coverage of individual national seismic networks precluded a precise earthquake location. In 2014, OGS, ARSO and ZAMG seismic networks participated in the creation of the Central and Eastern European Earthquake Research Network (CE 3 RN; http://www.CE3RN.eu/; Bragato et al., 2014). In order to extend CE 3 R Network monitoring towards earthquake early warning applications, at the end of 2013 OGS, ARSO and ZAMG teamed with the RISSC-Lab group at the Naples University Federico II in Italy. The collaboration focuses on testing the platform PRESTo (PRobabilistic and Evolutionary early warning SysTem) dev...
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Papers by Wolfgang Lenhardt