bluuebunny/crossref_metadata_2025_split huggingface dataset:
The new CAS-DIS digital ionosonde
Authors: Wang Shun  , Chen Ziwei  , Zhang Feng  , Fang Guangyou  
Published: June 2021

<p>A high quality digital ionosonde called the Chinese Academy of Sciences digital ionosonde (CAS-DIS) has been developed for investigations of the ionosphere. Two important features are used for the CAS-DIS; first, the technique of analog down-conversion has been replaced by the new approach of digital down-conversion technology. Secondly, to solve the problem of large instantaneous receiving bandwidth in digital receivers, an analog narrowband tracking filter is used for the CAS-DIS. The center frequency of the filter tracks the carrier frequency transmitted in real-time, to ensure that the frequency components are filtered out of the effective bandwidth. This report describes the system architecture of the CAS-DIS, its main features, and its test results for ionosphere detection.</p><p class="keywords"> </p>
Geotechnical characterization and seismic response of shallow geological formations in downtown Lisbon
Authors: Paula Teves-Costa  , Isabel M. Almeida  , Isabel Rodrigues  , Rita Matildes  , Claudia Pinto  
Published: June 2021

<p> </p><p>The geological and geotechnical characterization of shallow formations is one of the main steps in performing a microzonation study. This paper presents an example of the usefulness of the information compiled in a geological and geotechnical database for the estimation of the seismic response of the shallower formations of the Lisbon downtown area of Baixa. The geotechnical characterization of this area was performed based on the analysis of Standard Penetration Test (SPT) data compiled in the geological and geotechnical database. This database, connected to a geoscientific information system (CGIS), allows, also, the definition of 2D geological profiles used for estimating the thickness of the shallower layers. The shear-wave velocities (V<span><sub>S </sub></span>) for each layer were estimated from empirical correlations using mean SPT values computed from the statistical evaluation of the compiled data. These V<span><sub>S</sub></span> values were further calibrated with ambient vibration recording analysis. The seismic response of Baixa’s superficial deposits was estimated by applying a 1D equivalent linear method to a set of soil profiles, regularly distributed across the area, and using synthetic accelerograms to simulate input motions associated with probable earthquake occurrences in Lisbon. The results are presented in terms of maps of predominant frequencies, with the corresponding amplification level, as well as spectral amplification factors for 1 Hz and 2.5 Hz. The results show that the fundamental frequency of the Baixa area is between 1.2 Hz and 2 Hz, for the whole central valley, reaching 3 Hz near the edges where anthroprogenic and alluvial deposits have less expression. Amplification factors up to 5 were obtained. These results were achieved regardless of the considered input motion. The similarity of the obtained fundamental frequency with the natural frequency of Baixa’s old building stock increases the probability of resonance effects in future earthquakes.</p><p><span style="font-size: medium;"><br /></span></p>
Ensemble Forecasting of Volcanic Emissions in Hawai’i
Authors: Andre Kristofer Pattantyus  , Steven Businger  
Published: June 2021

<div class="page" title="Page 1"><div class="section"><div class="layoutArea"><div class="column"><p><span>Deterministic model forecasts do not convey to the end users the forecast uncertainty the models possess as a result of physics parameterizations, simplifications in model representation of physical processes, and errors in initial conditions. This lack of understanding leads to a level of uncertainty in the forecasted value when only a single deterministic model forecast is available. Increasing computational power and parallel software architecture allows multiple simulations to be carried out simultaneously that yield useful measures of model uncertainty that can be derived from ensemble model results. The Hybrid Single Particle Lagrangian Integration Trajectory and Dispersion model has the ability to generate ensemble forecasts. A meteorological ensemble was formed to create probabilistic forecast products and an ensemble mean forecast for volcanic emissions from the Kilauea volcano that impacts the state of Hawai’i. The probabilistic forecast products show uncertainty in pollutant concentrations that are especially useful for decision-making regarding public health. Initial comparison of the ensemble mean forecasts with observations and a single model forecast show improvements in event timing for both sulfur dioxide and sulfate aerosol forecasts. </span></p></div></div></div></div><p> </p>
Empirical relationships of shear wave velocity, SPT-N value and vertical effective stress for different soils in Mashhad, Iran
Authors: Azam Ghazi  , Naser Hafezi Moghadas  , Hosein Sadeghi  , Mohamad Ghafoori  , Gholam Reza Lashkaripur  
Published: June 2021

<p>Shear wave velocity, V<sub>s</sub>, is one of the important input parameters in seismic response analysis of the ground. Various methods have been examined to measure the soil V<sub>s</sub> directly. Direct measurement of V<sub>s</sub> is time consuming and costly, therefore many researchers have been trying to update empirical relationships between V<sub>s</sub> and other geotechnical properties of soils such as SPT Blow count, SPT-N. In this study the existence of a statistical relationship between V<sub>s</sub>, SPT-N<sub>60 </sub>and vertical effective stress, signa<sub>nu</sub>´, is investigated. Data set we used in this study was gathered from geotechnical and geophysical investigations reports. The data have been extracted from more than 130 numbers of geotechnical boreholes from different parts of Mashhad city. In each borehole the V<sub>s</sub> has been measured by downhole method at two meter intervals. The SPT test also has performed at the same depth. Finally relationships were developed by regression analysis for gravels, sands and fine grain soils. The proposed relationships indicate that V<sub>s</sub> is strongly dependent on signa<sub>nu</sub>´. In this paper the effect of fine percent also is considered on the V<sub>s</sub> estimation.</p>
Neural network multispectral satellite images classification of volcanic ash plumes in a cloudy scenario
Authors: Matteo Picchiani  , Marco Chini  , Stefano Corradini  , Luca Merucci  , Alessandro Piscini  , Fabio Del Frate  
Published: June 2021

<div class="WordSection1"><div class="page" title="Page 1"><div class="layoutArea"><div class="column"><p><span>This work shows the potential use of neural networks in the characterization of eruptive events monitored by satellite, through fast and automatic classification of multispectral images. The algorithm has been developed for the MODIS instrument and can easily be extended to other similar sensors. Six classes have been defined paying particular attention to image regions that represent the different surfaces that could possibly be found under volcanic ash clouds. Complex cloudy scenarios composed by images collected during the Icelandic eruptions of the Eyjafjallajökull (2010) and Grimsvötn (2011) volcanoes have been considered as test cases. A sensitivity analysis on the MODIS TIR and VIS channels has been performed to optimize the algorithm. The neural network has been trained with the first image of the dataset, while the remaining data have been considered as independent validation sets. Finally, the neural network classifier’s results have been compared with maps classified with several interactive procedures performed in a consolidated operational framework. This comparison shows that the automatic methodology proposed achieves a very promising performance, showing an overall accuracy greater than 84%, for the Eyjafjalla - jökull event, and equal to 74% for the Grimsvötn event. </span></p></div></div></div><p><em><br /></em></p><p><em><br /></em></p></div><em><br clear="all" /></em>
Volcanic SO2 by UV-TIR satellite retrievals: validation by using ground-based network at Mt. Etna
Authors: Claudia Spinetti  , Giuseppe Giovanni Salerno  , Tommaso Catalbiano  , Elisa Carboni  , Lieven Clarisse  , Stefano Corradini  , Roy Gordon Grainger  , Pascal Andre Hedelt  , Maria Elissavet Koukouli  , Luca Merucci  , Richard Siddans  , Lucia Tampellini  , Nicolas Theys  , Pieter Valks  , Claus Zehner  
Published: June 2021

<div class="page" title="Page 1"><div class="layoutArea"><div class="column"><p><span>Mt. Etna volcano in Italy is one of the most active degassing volcanoes worldwide, emitting a mean of 1.7 Mt/year of Sulphur Dioxide (SO</span><span>2</span><span>) in quiescent periods. In this work, SO</span><span>2 </span><span>measurements retrieved by Moderate Resolution Imaging Spectroradiometer (MODIS), hyper-spectral Infrared Atmospheric Sounding Interferometer (IASI) and the second Global Ozone Monitoring Experiment (GOME-2) data are compared with the ground-based data from the FLux Automatic MEasurement monitoring network (FLAME). Among the eighteen lava fountain episodes occurring at Mt. Etna in 2011, the 10 April paroxysmal event has been selected as a case-study for the simultaneous observation of the SO</span><span>2 </span><span>cloud by satellite and ground-based sensors. For each data-set two retrieval techniques were adopted and the measurements of SO</span><span>2 </span><span>mass and flux with their respective uncertainty were obtained. With respect to the FLAME SO</span><span>2 </span><span>mass of 4.5 Gg, MODIS, IASI and GOME-2 differ by about 10%, 15% and 30%, respectively. The SO</span><span>2 </span><span>flux correlation coefficient between MODIS and FLAME is 0.84. All the retrievals within the respective errors are in agreement with the ground-based measurements supporting the validity of these space measurements. </span></p></div></div></div>
The first ultra-high resolution Digital Terrain Model of the shallow-water sector around Lipari Island (Aeolian Islands, Italy)
Authors: Alessandro Bosman  , Daniele Casalbore  , Marco Anzidei  , Filippo Muccini  , Cosmo Carmisciano  , Francesco Latino Chiocci  
Published: June 2021

<p style="margin: 0cm 0cm 10pt; text-align: justify; line-height: 150%;"> </p><p>Very high resolution bathymetric map obtained through multibeam echo-sounders data are crucial to generate accurate Digital Terrain Models from which the morphological setting of active volcanic areas can be analyzed in detail. Here we show and discuss the main results from the first multibeam bathymetric survey performed in shallow-waters around the island of Lipari, the largest and the most densely populated of the Aeolian Islands (southern Italy). Data have been collected in the depth range of 0.1-150 m and complete the already existent high-resolution multibeam bathymetry realized between 100 and 1300 m water depth. The new ultra-high resolution bathymetric maps at 0.1-0.5 m provide new insights on the shallow seafloor of Lipari, allowing to detail a large spectrum of volcanic, erosive-depositional and anthropic features. Moreover, the presented data allow outlining the recent morphological evolution of the shallow coastal sector of this active volcanic island, indicating the presence of potential geo-hazard factors in shallow waters.</p><p style="margin: 0cm 0cm 10pt; text-align: justify; line-height: 150%;"><span style="line-height: 150%; font-family: 'Times New Roman','serif'; font-size: 12pt; mso-ansi-language: EN-US;" lang="EN-US"><span style="line-height: 150%; font-family: 'Times New Roman','serif'; font-size: 12pt; mso-ansi-language: EN-US;" lang="EN-US"><br /></span></span></p>
The local ionospheric modeling by integration ground GPS observations and satellite altimetry data
Authors: Mohammad Ali Sharifi  , Saeed Farzaneh  
Published: June 2021

<p>The free electrons in the ionosphere have a strong impact on the propagation of radio waves. When the signals pass through the ionosphere, both their group and phase velocity are disturbed. Several space geodetic techniques such as satellite altimetry, low Earth orbit (LEO) satellite and very long baseline interferometry (VLBI) can be used to model the total electron content. At present, the classical input data for development of ionospheric models are based on dual-frequency GPS observations, However, a major problem with this observation type is the nonuniform distribution of the terrestrial GPS reference stations with large gaps notably over the sea surface and ocean where only some single stations are located on islands, leading to lower the precision of the model over these areas. In these regions the dual-frequency satellite altimeters provide precise information about the parameters of the ionosphere. Combination of GPS and satellite altimetry observations allows making best use of the advantages of their different spatial and temporal distributions. In this study, the local ionosphere modeling was done by the combination of space geodetic observations using spherical Slepian function. The combination of the data from ground GPS observations over the western part of the USA and the altimetry mission Jason-2 was performed on the normal equation level in the least-square procedure and a least-square variance component estimation (LS-VCE) was applied to take into account the different accuracy levels of the observations. The integrated ionosphere model is more accurate and more reliable than the results derived from the ground GPS observations over the oceans.</p>
Ionospheric perturbations related to the earthquake in Vrancea area on November 22, 2014, as detected by electromagnetic VLF/LF frequency signals
Authors: Maria Solovieva  , Alexander Rozhnoi  , Viktor Fedun  , Konrad Schwingenschuh  , Masashi Hayakawa  
Published: June 2021

<p>Data from the European network of very low/ low frequency (VLF/LF) receivers has been used to study the response of the lower ionosphere to the earthquake of magnitude 5.5<strong> </strong>in Vrancea area on November 22, 2014. Negative amplitude anomalies have been observed during 3 days before the earthquake and two days after, on the LF (45.9 kHz) signal passed above the seismic area. No perturbations have been found for the same signal in control paths during this period. Other possible influences both from above and below which can produce perturbations in the ionosphere have been taken into consideration.</p>
A new MD-ML relationship for Mt. Etna earthquakes (Italy)
Authors: Tiziana Tuvè  , Salvatore D'Amico  , Elisabetta Giampiccolo  
Published: June 2021

<p class="Testoformula">A homogenous database of magnitude observations is a basic requirement for seismic hazard estimation and other seismic studies. Unfortunately, the magnitude reported in the seismic catalogue of Mt. Etna is not homogenous. Until 2005 only the duration magnitude (M<sub>D</sub>) is available, though since then the more stable local magnitude (M<sub>L</sub>) has also been calculated. To overcome this limitation, earthquake data recorded at Mt. Etna during the period 2005 – 2014 were used to derive a new relationship between local and duration magnitude, by applying the General Orthogonal Regression (GOR) which is an alternative to least squares when the ratio between errors on the independent and the dependent variables can be estimated. The relationship obtained is:</p><p class="Testoformula"> M<sub>L</sub> = 1.164 (± 0.011) * M<sub>D</sub> - 0.337 (± 0.020) </p><p> The new relationship allows to back-extend the local magnitude dataset to cover a period of about 15 years.</p>
Macroseismic intensity investigation of the November 2014, M=5.7, Vrancea (Romania) crustal earthquake
Authors: Angela Petruta Constantin  , Iren Adelina Moldovan  , Andreea Craiu  , Mircea Radulian  , Constantin Ionescu  
Published: June 2021

On November 22, 2014 at 21:14:17 local hour (19:14:17 GMT) a M<sub>L</sub>=5.7 crustal earthquake occurred in the area of Marasesti city of Vrancea county (Romania) - the epicenter was located at north latitude 45.87° and east longitude 27.16°, with a focal depth of 39 km. This earthquake is the main shock of a sequence that started with this and lasted until the end of January. During the sequence, characterized by the absence of foreshocks, a number of 75 earthquakes were recorded in 72 hours, the largest of which occurred in the same day with the main shock, at 22:30 (M<sub>L</sub>= 3.1). The crustal seismicity of Vrancea seismogenic region is characterized by moderate earthquakes with magnitudes that have not exceeded M<sub>W</sub> 5.9, this value being assigned to an earthquake that occurred in historical times on March 1, 1894 (Romplus catalogue). Immediately after the 2014 earthquake occurrence, the National Institute for Earth Physics (NIEP) sent macroseismic questionnaires in all affected areas, in order to define the macroseismic field of ground shaking. According to macroseismic questionnaires survey, the intensity of epicentral area reached VI MSK, and the seismic event was felt in all the extra-Carpathian area. This earthquake caused general panic and minor to moderate damage to the buildings in the epicentral area and the northeast part of country. The main purpose of this paper is to present the macroseismic map of the earthquake based on the MSK-64 intensity scale.
On feasibility to detect volcanoes hidden under the ice of Antarctica via their “gravitational signal”
Authors: Jaroslav Klokočník  , Jan Kostelecký  , Ivan Pešek  , Aleš Bezděk  
Published: June 2021

<p class="Prosttext1">Many undiscovered volcanoes may be hidden under the thick layers of the ice of Antarctica. Hypothetic volcanoes were sought by means of the best present-day gravitational data (gravity field model EIGEN 6C4) and bedrock topography data (Bedmap2). A new previously unused method was tested. The analogy with the “gravitational signal” typical for volcanoes and other structures in other parts of the Earth is used. Various functions (not only ordinary gravity anomalies) of the disturbing geopotential were employed: Marussi tensor of the second derivatives, geopotential invariants, the strike angle and the virtual deformations. We attempted to discover if the best present-day gravitational and topographic data are of sufficient precision and resolution and how fast is the attenuation of the “gravitational signal” of a volcano with increasing depth under the ice. It is shown that there is no principal obstacle to detect volcanoes by our method. However, it appeared very quickly that our present-day attempts to discover such volcanoes could hardly be successful, mainly due to a low resolution of the existing gravity data and also due to a low resolution of the best bedrock topography of Antarctica currently available. Nevertheless, some examples of hypothetical volcanoes under the ice are given, but they are uncertain. However, the method, the main goal of this feasibility study, is ready and working. <strong></strong></p>
Moment tensor solutions for the Amatrice 2016 seismic sequence
Authors: Silvia Pondrelli  , Simone Salimbeni  , Paolo Perfetti  
Published: June 2021

On August 24, 2016 a M<sub>L</sub> 6.0 earthquake struck central Italy region, nearly completely destroying some small ancient towns as Amatrice, Accumoli, Arquata and Pescara del Tronto. In the following days thousands of aftershocks have been recorded by the INGV National Seismometric Network, 16 of them with a magnitude greater than 4.0. A Quick RCMT solution has been rapidly computed for all of them and made available on the web. Within a few weeks a definitive RCMT solution is ready for all of them, plus one. For major events (and not only) of the Amatrice seismic sequence, several rapid moment tensor solutions have been produced by various groups, using different methods and dataset. Comparing QRCMTs with other similar products, it is evident a great similarity of focal mechanisms while on the contrary, the Mw have a clear variability.
Assessing soil-structure interaction during the 2016 Central Italy seismic sequence (Italy): preliminary results
Authors: Arrigo Caserta  , Fawzi Doumaz  , Antonio Costanzo  , Anna Gervasi  , William Thorossian  , Sergio Falcone  , Carmelo La Piana  , Mario Minasi  , Maria Fabrizia Buongiorno  
Published: June 2021

<p><em>We used the moderate-magnitude aftershocks succeeding to the 2016 August 24<sup>th</sup>, Mw = 6.0, Amatrice (Italy) mainshok to asses, specially during an ongoing seismic sequence, the soil-structure interaction where cultural Heritage is involved. We have chosen as case study the</em><em> San Giovanni Battista</em><em> church (A.D. 1039) in Acquasanta Terme town, about 20 Km northeast of Amatrice. First of all we studied the soil shaking features in order to characterize the input to the monument. Then, using the recordings in the church, we tried to figure out how the input seismic energy is distributed over the different monument parts. Some preliminary results are shown and discussed.</em></p><p><em><br /></em></p>
The role of INGVterremoti blog in information management during the earthquake sequence in Central Italy
Authors: Maurizio Pignone  , Concetta Nostro  , Alessandro Amato  , Carlo Meletti  
Published: June 2021

<p class="Normale1"><em>In this paper, we describe the role the INGVterremoti blog in information management during the first part of the earthquake sequence in central Italy (August 24 to September 30). In the last four years, we have been working on the INGVterremoti blog in order to provide quick updates on the ongoing seismic activity in Italy and in-depth scientific information. These include articles on specific historical earthquakes, seismic hazard, geological interpretations, source models from different type of data, effects at the surface, and so on.</em></p><p class="Normale1"><em>We have delivered information in quasi-real-time also about all the recent magnitude M≥4.0 earthquakes in Italy, the strongest events in the Mediterranean and in the world.</em></p><p class="Normale1"><em>During the 2016 central Italy, the INGVterremoti blog has continuously released information about seismic sequences with three types of posts: i) updates on the ongoing seismic activity; ii) reports on the activities carried out by the INGV teams in the field and any other working groups; iii) in-depth scientific articles describing some specific analysis and results.</em></p><p class="Normale1"><em>All the blog posts have been shared automatically and in real time on the other social media of the INGVterremoti platform, also to counter the bad information and to fight rumors. These include Facebook, Twitter and INGVterremoti App on IOS and Android. As well, both the main INGV home page (http://www.ingv.it) and the INGV earthquake portal (<span style="text-decoration: underline;">http://terremoti.ingv.it</span>) have published the contents of the blog on dedicated pages that were fed automatically. The work done day by day on the INGVterremoti blog has been coordinated with the INGV Press Office that has written several press releases based on the contents of the blog.</em></p><p class="Normale1"><em></em><em>Since August 24<sup>th</sup>, on the blog 53 articles were published on the blog they have had more than 1.9 million views and 1 million visitors. The peak in the number of views, which was more than 800,000 in a single day, was registered on August 24, 2016, following the M 6.0 earthquake.</em></p>