90 research outputs found
InversiĂłn del tensor momento sĂsmico de terremotos superficiales a distancias regionales
Tesis de la Universidad Complutense de Madrid, Facultad de Ciencias FĂsicas, Departamento de FĂsica de la Tierra, AstronomĂa y AstrofĂsica I, leĂda el 06-05-2005Depto. de FĂsica de la Tierra y AstrofĂsicaFac. de Ciencias FĂsicasTRUEpu
A new seismicity catalogue of the eastern Alps using the temporary Swath-D network
We present a new, consistently processed seismicity catalogue for the eastern and southern Alps based on the temporary dense Swath-D monitoring network.
The final catalogue contains 6053 earthquakes for the time period
2017â2019 and has a magnitude of completeness of â1.0âML. The smallest detected and located events have a magnitude of â1.7âML. Aimed at the low to moderate seismicity in the study region, we have developed a multi-stage, mostly automatic workflow that combines a priori information from local catalogues and waveform-based event detection, subsequent efficient GPU-based (GPU: graphics processing unit) event search by template matching, P and S arrival time pick refinement, and location in a regional 3-D velocity model.
The resulting seismicity distribution generally confirms the previously identified main seismically active domains but provides increased resolution of the fault activity at depth.
In particular, the high number of small events additionally detected by the template search contributes to a denser catalogue and provides an important basis for future geological and tectonic studies in this complex part of the Alpine orogen
SEISMOLOGICAL ANALYSIS OF THE 1917 MONTERCHI EARTHQUAKE (CENTRAL APENNINES, ITALY) FOR SEISMOTECTONIC IMPLICATIONS
On April 26, 1917 at 9:35:59 (GMT) an earthquake occurred in the Sansepolcro Basin (the northernmost portion of the High Tiber Valley - Italy) producing large damages and fatalities. This event, noted as Monterchi earthquake, is well constrained in the Catalogue of Strong Italian Earthquakes (Boschi et al., 2000) by 134 felt reports locations, mainly distributed on the right side of the Tiber Valley, mostly affecting the towns of Monterchi, Citerna and surrounding localities. The maximum and epicentral intensity was determined as Io=IX-X degree of the MCS scale corresponding to an equivalent magnitude of Me=6 that define this event as the most important of the region.
The Sansepolcro Basin was generated on the hanging-wall of the Altotiberina Fault (ATF) system. The ATF system is composed by an E-dipping low-angle normal fault, active at least since the Late Pliocene, that represents one of the main regional detachments of the Northern Apennines, and its antithetic W-dipping high-angle normal faults (Barchi, et al., 2009, Boncio et al., 2000). Although the southern part of the ATF was demonstrated to creep (Piccinini et al., 2003), its capability to generate strong or moderate earthquakes is still debated and the historical seismicity that affected the region was not associated to specific geologic sources.
For these reasons the study of the Monterchi earthquake plays an important role in the debate. On this light, many authors tried to define the main seismic source parameters through the analysis of historical seismograms and respective bulletins. Preliminary results were presented at previous ECEES, ESC and EGU congresses (Caciagli et al., 2006, Ciaccio et al., 2008, Bernardi et al., 2009). In all these works the hypocentre of the Monterchi earthquake has been substantially unresolved, because of the absolute P and S-phases use, and, for this reason, its epicentre was located 20 km North of the macroseismic one.
Concerning the focal mechanism, Bernardi et al. (2009) proposed a moment tensor solution for the Monterchi event, based on almost horizontal recordings from 4 stations situated in a very small azimuthal range. Independently of the validity of the normal fault mechanism proposed by Bernardi et al (2009) their conclusions fit perfectly in the context of the seismotectonic setting of the ATF, but do not account for the discrepancy between the instrumental and the macroseismic epicentres.
Today, 49 seismograms from 19 different Euro-Mediterranean observatories are available in the database of the SISMOS Project â INGV (http://sismos.rm.ingv.it/)
The BAAS (British Association for Advancement of Sciences) bulletin of 1917, although if incomplete because of the 1st World War, reports a list of 21 seismological observatories that recorded the P and S-phases for this earthquake. Additionally to this database, we included additional arrival-times deriving from further seismic bulletins not contained in the BAAS reports and from directly digitizing original historical seismograms. An incisive approach to analyse these different data allows us to obtain a new, robust and consistent hypocentral solution, coherent with the macroseismic data, in particular by using S-P travel time differences for recordings where the absolute timing is uncertain.
An accurate research on the technical characteristics of the recording historical seismometers (period, damping, gain etc), including the analysis of the instrumental natural period recorded in some seismograms, allows to deconvolute the original digitized seismic traces in order to evaluate the potential of moment tensor inversion, to determine the main seismic parameters (Mo, Mw, Circular Fault Radius), and to implement the solution in the framework of the regional tectonic setting
Hyperbaric oxygen treatment of superficial soft tissue lesions in children with oncologic disease
This study aimed to assess the feasibility and results of hyperbaric oxygen therapy (HOT) as supportive treatment of lesions of superficial soft tissues in children with oncological diseases. This was a retrospective analysis and review of all records of children observed at the Pediatric Hematology-Oncology Department of the University of Padova and treated adjuvantly with HOT. Between 1996 and 2010, 12 patients (5 males and 7 females, median age 7 years, range 0.5â16) underwent HOT. The effectiveness of HOT varied according to the lesion treated. Ten out of 12 patients were cured. Efficacy was most questionable in 2 patients with skin graft and flaps at risk. Compliance to therapy was close to 100%. In just one case, HOT was interrupted for the appearance of local skin metastases close to the site of primary tumor. HOT showed itself to be safe and effective in most patients even those immunocompromised or critically ill
Seismotectonics of the Eastern Alps: New insights from earthquake studies within 4D-MB
The recent installation of the dense SWATH-D network in the Eastern Alps, integrated into the broader AlpArray, provides the basis for new detailed and consistent studies of small to moderate seismicity. In the SPP project âFrom Top to Bottom â Seismicity, motion patterns and stress distribution in the Alpine crustâ and the follow-up project âConstraints on quaternary processes in the Eastern Alps from a new detailed image of seismicityâ, we have focused on event detection, precise location, analysis of seismicity clustering and detailed source parameter studies, involving methodological advancements and subsequent application to the seismological SWATH-D and AlpArray data.
Here, we summarize the main results of our completed and ongoing work:
1. We have developed a new, python-based tool for automated station quality control of dense seismic networks and arrays and applied it successfully to the permanent and temporary AlpArray networks as well as to the denser SWATH-D network (AutoStatsQ, [Petersen et al., 2019]). The toolbox uses a combination of observed and synthetic teleseismic event data to identify and quantify errors in amplitude gain and sensor orientation and to correct the stations accordingly.
2. Based on methodological tests adapted for the complex tectonic setting in the Alps, we have performed centroid moment tensor inversion of seismicity with MW â„ 3.0 recorded by the AlpArray network and compared the solutions to historical earthquakes, recent seismicity, published focal mechanisms, and GNSS deformation data ([Petersen et al., 2021]). We additionally applied epicenter clustering to resolve in detail the heterogeneity of tectonic movement. Thrust faulting is dominant in the Friuli area of the eastern Southern Alps, related to the NâS convergence of the Eurasian and Adriatic plate and counterclockwise rotation of Adria relative to Europe. Strikeslip faulting with similarly oriented P- axes is observed along the northern margin of the Central Alps and in the northern Dinarides, consistent with right-lateral strike-slip faults and high shear strain rates. The NW Alps exhibit deviant behavior, with NWâSE-striking normal faulting events and NEâSW-oriented T- axes. Faulting styles in the SW Alps are more heterogeneous, with a majority of earthquakes related to an extensional stress regime.
3. We have designed a workflow which combines a priori information from local catalog and waveformbased event detection, subsequent GPU-based event search by template matching, P & S arrival time pick refinement and location in a regional 3-D velocity model. Application to the SWATH-D data provided for the first time a consistently processed seismicity catalog for the Eastern and Southern Alps, which has a magnitude of completeness of â1.0 ML, involves event classification and includes > 6, 000 earthquakes [Hofman et al., 2023a]. The newly revealed clusters better illuminate the fault structures at depth, and we detected and located additional, mostly weak events, a part of them pointing to small, but active upper crustal deformation in the Dolomite indenter, along the Pustertal-Gailtal Fault and in the Tauern window.
4. In our ongoing work, we characterize the earthquake distribution in more detail, using novel approaches from Graph theory, waveform similarity based clustering and stacked- waveform moment tensor Inversion [Hofman et al., 2023b], [Petersen et al., 2020], [Petersen et al., 2023]
Systematic Changes of Earthquake Rupture with Depth: A Case Study from the 2010Mw 8.8 Maule, Chile, Earthquake Aftershock Sequence
The very shallow part of subduction megathrusts occasionally hosts tsunami earthquakes, with unusually slow rupture propagation. The aftershock sequence of the 2010 Mw 8.8 Maule earthquake, offshore Chile, provides us with the opportunity to study systematic changes in source properties for smaller earthquakes within a single segment of a subduction zone. We invert amplitude spectra for double-couple moment tensors and centroid depths of 71 aftershocks of the Maule earthquake down to magnitudes Mw 4.0. In addition, we also derive average source durations.We find that shallower earthquakes tend to have longer normalized source durations on average, similar to the pattern observed previously for larger magnitude events. This depth dependence is observable for thrust and normal earthquakes. The normalized source durations of normal- faulting earthquakes are at the lower end of those for thrust earthquakes, probably because of the higher stress drops of intraplate earthquakes compared to interplate earthquakes. We suggest from the similarity of the depth dependence of normal and thrust events and between smaller and larger magnitude earthquakes that the depth-dependent variation of rigidity, rather than frictional conditional stability at the plate interface, is primarily responsible for the observed pattern. Tsunami earthquakes probably require both low rigidity and conditionally stable frictional conditions; the presence of longduration moderate-magnitude events is therefore a helpful but not sufficient indicator for areas at risk of tsunami earthquakes
INFLUĂNCIA DE UM DISPOSITIVO INTRAVAGINAL PARA SINCRONIZAĂĂO/INDUĂĂO DE ESTROS E SUA REUTILIZAĂĂO NA FLORA VAGINAL OVINA
O objetivo neste estudo foi caracterizar a flora bacteriana vaginal e a sua susceptibilidade aos antibiĂłticos in vitro apĂłs o emprego e a reutilização de um dispositivo intravaginal de progesterona (CIDR) empregado para o controle do ciclo estral na espĂ©cie ovina. Foram utilizadas 30 borregas da raça Texel, as quais, apĂłs serem avaliadas quanto ao seu estado sanitĂĄrio e corporal, formaram os grupos experimentais CIDR novo (CIDRn, n=15) e CIDR usado (CIDRu, n=15). O tratamento com progesterona foi de seis dias. As amostras do conteĂșdo vaginal foram coletadas no momento prĂ©vio Ă colocação dos dispositivos e na retirada destes com auxĂlio de swabs esterilizados mantidos em refrigeração em meio de transporte apropriado atĂ© o seu processamento. A flora predominante prĂ©via Ă inserção dos dispositivos intravaginais mostrou ser 93,3% (14/15) e 80,0% (12/15) de agentes gram positivos, especialmente dos gĂȘneros Bacillus sp. e Staphylococcus sp. nos grupos CIDRn e CIDRu, respectivamente. No momento da retirada dos dispositivos, entretanto, foi verificado o aparecimento de agentes gram negativos em 100% das amostras do grupo CIDRn, sendo a maioria pertencente ao gĂȘnero das EnterobactĂ©rias. JĂĄ no grupo CIDRu, houve um equilĂbrio entre agentes gram negativos e positivos na retirada dos dispositivos. Quanto Ă susceptibilidade, todas as amostras de microorganismos encontradas apresentaram alguma resistĂȘncia e sensibilidade aos princĂpios ativos testados. Conclui-se que os dispositivos intravaginais (CIDR), quando empregados em primeiro uso ou reutilizados por perĂodos de seis dias, promovem uma mudança de flora vaginal na espĂ©cie ovina, predominando agentes gram negativos na sua retirada.Palavras-chave: CIDR. EnterobactĂ©rias sp. Flora vaginal. Staphylococcus sp. Ovino.
SHEER âsmartâ database: technical note
The SHEER database brings together a large amount of data of various types: interdisciplinary site data from seven independent episodes, research data and those for the project results dissemination process. This concerns mainly shale gas exploitation test sites, processing procedures, results of data interpretation and recommendations. The smart SHEER database harmonizes data from different fields (geophysical, geochemical, geological, technological, etc.), creates and provides access to an advanced database of case studies of environmental impact indicators associated with shale gas exploitation and exploration, which previously did not exist. A unique component of the SHEER database comes from the monitoring activity performed during the project in one active shale gas exploration and exploitation site at Wysin, Poland, which started from the pre-operational phase. The SHEER database is capable of the adoption of new data such as results of other Work Packages and has developed an over-arching structure for higher-level integration
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