Synoptic view on sub-ionospheric VLF/LF amplitude and phase variations at the Graz seismo-electromagnetic facility

2021 ◽  
Author(s):  
Hans Eichelberger ◽  
Konrad Schwingenschuh ◽  
Mohammed Y. Boudjada ◽  
Bruno P. Besser ◽  
Daniel Wolbang ◽  
...  
Keyword(s):  
Seismic Events ◽  
Coupling Mechanism ◽  
Natural Disturbances ◽  
Seismic Zone ◽  
External Forcing ◽  
Physical Processes ◽  
Large Area ◽  
International Networks ◽  
Space Research Institute ◽  
Phase Variations

<p>This presentation discusses physical processes related to potentially seismic and non-seismic disturbances along VLF/LF paths measured with two different receivers located side by side at the Space Research Institute (IWF) facility in Graz, Austria. At the same time both systems are embedded in international networks which gives the unique opportunity to probe the waveguide cavity over a large area.<br>In general, a variety of VLF/LF amplitude and phase variations are ubiquitous at wide scales throughout the cavity. We analyse such signals observed in the period 2018-2020 (solar minimum, i.e. less external forcing of the upper ionospheric boundary) in the time- and frequency-domain for several paths. In this attempt we aim to single out natural disturbances, characterise the source event, and figure out the lithosphere-atmosphere-ionosphere coupling mechanism. For known seismic events we consider the so-called Dobrovolsky-Bowman relationship [1,2] allowing to estimate the pre-seismic zone crossed by the VLF/LF paths.<br>The findings open up good prospects for an automated monitoring and characterisation of source phenomena who affect the electric field of VLF/LF sub-ionospheric links.</p><p>Ref:<br>[1] Dobrovolsky, I.P., Zubkov, S.I., and Miachkin, V.I., Estimation of the size of earthquake preparation zones, PAGEOPH 117, 1025–1044, 1979.<br>https://doi.org/10.1007/BF00876083<br>[2] Bowman, D.D., Ouillon, G., Sammis, C.G., Sornette, A., and Sornette, D., An observational test of the critical earthquake concept, JGR Solid<br>Earth, 103, B10, 24359-24372, 1998. https://doi.org/10.1029/98JB00792</p>

scholarly journals A NuSTAR confirmation of the 36 ks hard X-ray pulse-phase modulation in the magnetar 1E 1547.0 − 5408

2021 ◽  
Vol 502 (2) ◽  
pp. 2266-2284
Author(s):  
Kazuo Makishima ◽  
Teruaki Enoto ◽  
Hiroki Yoneda ◽  
Hirokazu Odaka
Keyword(s):  
Time Lapse ◽  
Phase Behaviour ◽  
Modulation Amplitude ◽  
Axial Deformation ◽  
Physical Processes ◽  
Arrival Times ◽  
Pulse Phase ◽  
Phase Variations ◽  
Complex Phenomena ◽  
Made In

ABSTRACT This paper describes an analysis of the NuSTAR data of the fastest-rotating magnetar 1E 1547 − 5408, acquired in 2016 April for a time lapse of 151 ks. The source was detected with a 1–60 keV flux of 1.7 × 10−11 erg s−1 cm−2, and its pulsation at a period of 2.086710(5) s. In 8–25 keV, the pulses were phase-modulated with a period of T = 36.0 ± 2.3 ks, and an amplitude of ∼0.2 s. This reconfirms the Suzaku discovery of the same effect at $T=36.0 ^{+4.5}_{-2.5}$ ks, made in the 2009 outburst. These results strengthen the view derived from the Suzaku data, that this magnetar performs free precession as a result of its axial deformation by ∼0.6 × 10−4, possibly caused by internal toroidal magneti fields (MFs) reaching ∼1016 G. Like in the Suzaku case, the modulation was not detected in energies below ∼8 keV. Above 10 keV, the pulse-phase behaviour, including the 36 ks modulation parameters, exhibited complex energy dependencies: at ∼22 keV, the modulation amplitude increased to ∼0.5 s, and the modulation phase changed by ∼65° over 10–27 keV, followed by a phase reversal. Although the pulse significance and pulsed fraction were originally very low in >10 keV, they both increased noticeably, when the arrival times of individual photons were corrected for these systematic pulse-phase variations. Possible origins of these complex phenomena are discussed, in terms of several physical processes that are specific to ultrastrong MFs.

scholarly journals Cyclic patterns in the central European tick-borne encephalitis incidence series

2016 ◽  
Vol 145 (2) ◽  
pp. 358-367 ◽  
Author(s):  
P. ZEMAN
Keyword(s):  
External Factors ◽  
Disease Dynamics ◽  
Large Area ◽  
Climatic Forcing ◽  
Human Contact ◽  
Cyclic Patterns ◽  
Tick Borne Encephalitis ◽  
Synchronization Signal ◽  
Phase Variations ◽  
High Degree

SUMMARYTick-borne encephalitis (TBE) is peculiar due to its unstable dynamics with profound inter-annual fluctuations in case numbers – a phenomenon not well understood to date. Possible reasons – apart from variable human contact with TBE foci – include external factors, e.g. climatic forcing, autonomous oscillations of the disease system itself, or a combined action of both. Spectral analysis of TBE data from six regions of central Europe (CE) revealed that the ostensibly chaotic dynamics can be explained in terms of four superposed (quasi-)periodical oscillations: a quasi-biennial, triennial, pentennial, and a decadal cycle. These oscillations exhibit a high degree of regularity and synchrony across CE. Nevertheless, some amplitude and phase variations are responsible for regional differences in incidence patterns. In addition, periodic changes occur in the degree of synchrony in the regions: marked in-phase periods alternate with rather off-phase periods. Such a feature in the disease dynamics implies that it arises as basically diverging self-oscillations of local disease systems which, at intervals, receive synchronizing impulses, such as periodic variations in food availability for key hosts driven by external factors. This makes the disease dynamics synchronized over a large area during peaks in the synchronization signal, shifting to asynchrony in the time in between.

High Frequency Inversion Capacitance Measurements for 6H-SiC n-MOS Capacitors from 450 to 600 °C

2008 ◽  
Vol 600-603 ◽  
pp. 739-742 ◽  
Author(s):  
Ruby N. Ghosh ◽  
Reza Loloee ◽  
Tamara Isaacs-Smith ◽  
John R. Williams
Keyword(s):  
High Frequency ◽  
Operating Conditions ◽  
Oxide Semiconductor ◽  
Electrical Characteristics ◽  
Physical Processes ◽  
Large Area ◽  
Thermal Generation ◽  
Mos Capacitors ◽  
Mos Devices ◽  
Minority Carriers

The operation of metal-oxide-semiconductor (MOS) devices based on the semiconductor SiC in high temperature environments above 300 °C requires an understanding of the physical processes in these capacitor structures under operating conditions. In this study we have focused on the regime of inversion biasing, where the electrical characteristics of the device are dominated by minority carriers. We report on the direct observation of the high frequency inversion capacitance due to thermal generation of holes in 6H-SiC n-MOS capacitors between 450 and 600 °C by monitoring the 1MHz C-V characteristics of large area, 1000 μm diameter, capacitors in the dark. Our experimental results are consistent with a first order calculation based on the delta depletion approximation.

scholarly journals Physical Processes during the Formation of Silicon-Lithium p-i-n Structures Using Double-Sided Diffusion and Drift Methods

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5174
Author(s):  
Ahmet Saymbetov ◽  
Ramizulla Muminov ◽  
Nursultan Japashov ◽  
Yorkin Toshmurodov ◽  
Madiyar Nurgaliyev ◽  
...  
Keyword(s):  
Reverse Bias ◽  
Radiation Detectors ◽  
Monocrystalline Silicon ◽  
Reverse Bias Voltage ◽  
Optimal Temperature ◽  
Physical Processes ◽  
Large Area ◽  
Lithium Ions ◽  
Crystal Volume ◽  
Manufacturing Time

In this paper, we described a method of double-sided diffusion and drift of lithium-ions into monocrystalline silicon for the formation of the large-sized, p-i-n structured Si(Li) radiation detectors. The p-i-n structure is a p-n junction with a doped region, where the “i-region” is between the n and the p layers. A well-defined i-region is usually associated with p or n layers with high resistivities. The p-i-n structure is mostly used in diodes and in some types of semiconductor radiation detectors. The uniqueness of this method is that, in this method, the processes of diffusion and drift of lithium-ions, which are the main processes in the formation of Si(Li) p-i-n structures, are produced from both flat sides of cylindrical-shaped monocrystalline silicon, at optimal temperature (T = 420 °C) conditions of diffusion, and subsequently, with synchronous supply of temperature (from 55 to 100 °C) and reverse bias voltage (from 70 to 300 V) during drift of lithium-ions into silicon. Thus, shortening the manufacturing time of the detector and providing a more uniform distribution of lithium-ions in the crystal volume. Since, at present, the development of manufacturing of large-sized Si(Li) detectors is hindered due to difficulties in obtaining a uniformly compensated large area and time-consuming manufacturing process, the proposed method may open up new possibilities in detector manufacturing.

New simplified models for earthquake-triggered landslides in large area: application to Italian case studies

2021 ◽  
Author(s):  
Amerigo Mendicelli ◽  
Federico Mori ◽  
Gaetano Falcone ◽  
Edoardo Peronace ◽  
Massimiliano Moscatelli ◽  
...  
Keyword(s):  
Site Effects ◽  
Seismic Event ◽  
Amplification Factor ◽  
Rapid Assessment ◽  
Seismic Events ◽  
Large Area ◽  
Intensity Measures ◽  
Surface Level ◽  
Italian Case ◽  
Main Shocks

<p>Shake maps, produced a few hours after a seismic event, represent the key input for the rapid assessment of earthquake triggered landslides scenario maps in near real time.</p><p>The IGAG20 approach (Falcone et al., 2021) improves the prediction of these by contemplating the site effects that are calculated as a function of the V<sub>s30</sub> (Mori, 2020) and the intensity of the shaking.</p><p>The method originally calculates the amplification factor for some intensity measures at the surface level for the national hazard, in Italy.</p><p>Here, we present applications of the method, in terms of scenarios, for a few main shocks of past seismic events in Italy: Friuli 1976, Umbria-Marche 1997 and L’Aquila 2009. We used the OpenQuake engine (Silva et al., 2014), to produce PGV and PGA stochastic maps including amplification factors. The PGV map helped calculating landslide probability maps within the Nowicki et al. (2018) model, while the PGA map was a key input for landslide rockfall maps obtained within the STONE model (Antonini et al., 2002, Guzzetti et al., 2002; Alvioli 2020).</p><p>Results of both models were compared with available landslide records for the corresponding earthquake events, either in the form of points or polygons (Govi 1977; Guzzetti et al 2009).</p>

scholarly journals The Campotosto linkage fault zone between the 2009 and 2016 seismic sequences of central Italy: Implications for seismic hazard analysis

2020 ◽  
Author(s):  
Emanuele Tondi ◽  
Danica Jablonská ◽  
Tiziano Volatili ◽  
Maddalena Michele ◽  
Stefano Mazzoli ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Fault Zone ◽  
Central Italy ◽  
Seismic Events ◽  
Seismic Gap ◽  
Seismic Zone ◽  
Seismic Sequence ◽  
Geological Evidence ◽  
Seismic Sequences ◽  
Seismogenic Faults

In the last decade central Italy was struck by devastating seismic sequences resulting in hundreds of casualties (i.e., 2009-L′Aquila moment magnitude [Mw] = 6.3, and 2016-Amatrice-Visso-Norcia Mw max = 6.5). These seismic events were caused by two NW-SE−striking, SW-dipping, seismogenic normal faults that were modeled based on the available focal mechanisms and the seismic moment computed during the relative mainshocks. The seismogenic faults responsible for the 2009-L′Aquila Mw = 6.3 (Paganica Fault—PF) and 2016-Amatrice-Visso-Norcia Mw max = 6.5 (Monte Vettore Fault—MVF) are right-stepping with a negative overlap (i.e., underlap) located at the surface in the Campotosto area. This latter was affected by seismic swarms with magnitude ranging from 5.0 to 5.5 during the 2009 seismic sequence and then in 2017 (i.e., a few months later than the mainshocks related with the 2016 seismic sequence). In this paper, the seismogenic faults related to the main seismic events that occurred in the Campotosto Seismic Zone (CSZ) were modeled and interpreted as a linkage fault zone between the PF and MVF interacting seismogenic faults. Based on the underlap dimension, the seismogenic potential of the CSZ is in the order of Mw = 6.0, even in the case that all the faults belonging to the zone were activated simultaneously. This has important implications for seismic hazard assessment in an area dominated by the occurrence of a major NW-SE−striking extensional structure, i.e., the Monte Gorzano Fault (MGF). Mainly due to its geomorphologic expression, this fault has been considered as an active and silent structure (therefore representing a seismic gap) able to generate an earthquake of Mw max = 6.5−7.0. However, the geological evidence provided with this study suggests that the MGF is of early (i.e., pre- to syn-thrusting) origin. Therefore, the evaluation of the seismic hazard in the Campotosto area should not be based on the geometrical characteristics of the outcropping MGF. This also generates substantial issues with earthquake geological studies carried out prior to the recent seismic events in central Italy. More in general, the 4-D high-resolution image of a crustal volume hosting an active linkage zone between two large seismogenic structures provides new insights into the behavior of interacting faults in the incipient stages of connection.

scholarly journals Unification of data from various seismic catalogues to study seismic activity in the Carpathians Mountain arc

2019 ◽  
Vol 11 (1) ◽  
pp. 837-842
Author(s):  
Agnieszka Braclawska ◽  
Adam Filip Idziak
Keyword(s):  
Central Europe ◽  
Seismic Data ◽  
Seismic Activity ◽  
Earthquake Catalogue ◽  
Active Area ◽  
Seismic Events ◽  
Large Area ◽  
Carpathian Mountains ◽  
The Carpathians ◽  
Seismic Networks

Abstract The Carpathian Mountainsarc is the most seismically active area in Central Europe. Analysis of the seismicity of entire Carpathian arc requires data from each of the particular catalogues which have to be properly and uniformly entered, standardized and merged. For our study we first had to prepare a database of seismic events (ML ≥ 1.6) compiled from the data of earthquakes taken from individual national seismic networks as well as data from international seismic centers. However, a careful review of these catalogues has uncovered significant inconsistencies, particularly discrepancies in the description of the location, magnitude and completeness of seismic events. To address these inconsistencies, a newly created compound earthquake catalogue was compiled from the aforementioned seismic catalogues and included events that occurred in the Carpathian Mountains arc area between 1976 and 2017. This work is intended to point out some of the problems associated with collecting data from various seismic catalogues as well as the need for their very careful verification, in order to create a uniform set of seismic data across a large area spanning numerous countries. The results suggest that compiling a uniform and dependable earthquake catalogue is crucial for reliable seismic studies.

Models of the distribution and abundance of ground-dwelling mammals in the eucalypt forests of south-eastern New South Wales

1998 ◽  
Vol 25 (5) ◽  
pp. 449 ◽  
Author(s):  
P. C. Catling ◽  
R. J. Burt ◽  
R. I. Forrester
Keyword(s):  
Environmental Variables ◽  
New South ◽  
New South Wales ◽  
Natural Disturbances ◽  
Large Area ◽  
South Eastern ◽  
South Wales ◽  
Arboreal Marsupials ◽  
Eucalypt Forests ◽  
Habitat Variables

We examined the relationship between ground-dwelling mammals and the environment within 500 000 ha of eucalypt forest in south-eastern New South Wales. Ground-dwelling mammals were surveyed at 368 sites in 13 areas in relation to four habitat variables/factors, seven environmental variables, and two derived variables (‘disturbance’ and ‘prey abundance’). Habitat variables are vegetative variables such as eucalypt community and forest structure that may be altered by man (e.g. logging) or natural disturbances (e.g. wildfire). Environmental variables are climatic or topographic variables such as rainfall or lithology that cannot be altered by man or natural disturbances. Statistical models are presented of the distribution and abundance of ground-dwelling mammals in temperate eucalypt forests. From studies of the prediction of eucalypt species from environmental variables and the distribution of arboreal marsupials it has been possible previously to map the predicted density of arboreal marsupials for a large area of south-eastern New South Wales. It would be difficult to do the same for the ground-dwelling mammals because of the importance of structural variables and the influence of disturbance on structure. However, there appears to be a positive relationship between the abundance of some ground-dwelling mammals and environmental variables such as the lithology nutrient rating. Many past studies of fauna have stratified sampling on broad climatic and terrain variables and not included an adequate proportion of the structural variation, which may remain concealed as a large part of the unexplained variation. This may be the single most important problem facing reliable modelling and prediction of patterns of biodiversity in eucalypt forests.

Use of archaeology to date liquefaction features and seismic events in the New Madrid seismic zone, Central United States

1996 ◽  
Vol 11 (6) ◽  
pp. 451-480 ◽  
Author(s):  
Martitia P. Tuttle ◽  
Robert H. Lafferty ◽  
Margaret J. Guccione ◽  
Eugene S. Schweig ◽  
Neal Lopinot ◽  
...  
Keyword(s):  
United States ◽  
Seismic Events ◽  
New Madrid Seismic Zone ◽  
Seismic Zone ◽  
Central United States ◽  
New Madrid

scholarly journals Probabilistic seismic hazard maps for the North Balkan region

1999 ◽  
Vol 42 (6) ◽  
Author(s):  
R. M. W. Musson
Keyword(s):  
Seismic Hazard ◽  
Seismic Source ◽  
Source Model ◽  
Seismic Zone ◽  
Hazard Maps ◽  
Large Area ◽  
Ground Acceleration ◽  
Seismic Hazard Maps ◽  
The North ◽  
Seismic Source Model

A set of seismic hazard maps, expressed as horizontal peak ground acceleration, have been computed for a large area of Central and Eastern Europe covering the North Balkan area (Former Yugoslavia, Hungary, Romania). These are based on: a) a compound earthquake catalogue for the region; b) a seismic source model of 50 zones compiled on the basis of tectonic divisions and seismicity, and c) a probabilistic methodology using stochastic (Monte Carlo) modelling. It is found that the highest hazard in the region comes from intermediate focus earthquakes occurring in the Vrancea seismic zone; here the hazard exceeds 0.4 g at return periods of 475 years. Special account has been taken of the directional nature of attenuation from this source.

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