New insights on the Messina 1908 seismic source from post-seismic sea level change

The identification of a source model for the catastrophic 1908 December 28 Messina earth- quake (Mw = 7.2) has been the subject of many papers in the last decades. Several authors proposed different models on the basis of seismological, macroseismic and geodetic data sets; among these models, remarkable differences exist with regard to almost all parameters. We selected a subset of six models among those most cited in literature and used them to model the post-seismic sea level variation recorded at the tide gauge station of Messina (until 1923), to attempt an independent discrimination among them. For each model, we assumed a simple rheological structure and carried out a direct-search inversion of upper crust thickness and lower crust viscosity to fit the post-seismic sea level signal. This approach enabled us to iden- tify a class of fault geometries which is consistent with the post-seismic signal at the Messina tide gauge and with the known structural and rheological features of the Messina strai

Post-seismic stress relaxation with a linear transient rheology

We performed an analysis of post-seismic stress relaxation, taking into account generalized linear rheologies. We compared the stress field (and its derived functions) obtained with a classical Maxwell rheology with that obtained with a transient Burgers body. From a set of synthetic case studies, we have revealed quantitative and qualitative differences both in relaxation times and in local stress values when a transient rheology is introduced. As a practical application, we modeled the time evolution of the Coulomb failure function following the 2009 L'Aquila earthquake, and we show that a transient rheology can lead to non-monotonic time dependence

Application of the Post-Widder Laplace inversion algorithm to postseismic rebound models

The postseismic response of a viscoelastic Earth can be computed analytically with a normal-mode approach, based on the application of propagator methods. This framework suffers from many limitations, mostly connected with the solution of the secular equation, whose degree scales with the number of viscoelastic layers so that only low-resolution models can be practically solved. Recently, a viable alternative to the normal-mode approach has been proposed, based on the Post-Widder inversion formula. This method allows to overcome some of the intrinsic limitations of the normal-mode approach, so that Earth models with arbitrary radial resolution can be employed and general linear non-Maxwell rheologies can be implemented. In this work, we test the robustness of the method against a standard normal-mode approach in order to optimize computation performance while ensuring the solution stability. As an application, we address the issue of finding the minimum number of layers with distinct elastic properties needed to accurately describe the postseismic relaxation of a realistic Earth model

Kinematics and Source Zone Properties of the 2004 Sumatra-Andaman Earthquake and Tsunami: Nonlinear Joint Inversion of Tide-Gage, Satellite Altimetry and GPS data

We (re)analyzed the source of the 26 December 2004 Sumatra-Andaman earthquake and tsunami through a nonlinear joint inversion of an in-homogeneous dataset made up of tide-gages, satellite altimetry, and far-field GPS recordings. The purpose is two-fold: (1) the retrieval of the main kinematics rupture parameters (slip, rake, rupture velocity); (2) the inference of the rigidity of the source zone. We independently estimate the slip from tsunami data and the seismic moment from geodetic data, so to derive the rigidity. Our results confirm that the source of the 2004 Sumatra-Andaman earthquake has a complex geometry, constituted by three main slip patches, with slip peaking at ~30 meters in the Southern part of the source. The rake direction rotates counter-clockwise at North, according to the direction of convergence along the trench. The rupture velocity is higher in the deeper than in the shallower part of the source, consistently with the expected increase of rigidity with depth. It is also lower in the Northern part, consistently with known variations of the incoming plate properties and shear velocity. Our model features a rigidity (20-30 GPa), that is lower than PREM average for the seismogenic volume [Dziewonski and Anderson, 1981]. The source rigidity is one of the factors controlling the tsunamigenesis: for a given seismic moment, the lower the rigidity, the higher the induced seafloor displacement. The general consistence between our source model and previous studies supports the effectiveness of our approach to the joint inversion of geodetic and tsunami data for the rigidity estimation

Hubungan Antara Beban Kerja Dengan Stres Kerja Pada Perawat Pelaksana Di Ruang Isolasi Covid-19 Rumah Sakit Umum Daerah Kota Kotamobagu

Dampak dari wabah Coronavirus Disease of 2019 (COVID-19) menimbulkan pengaruh yang serius pada tenaga kesehatan. Dampak yang paling berpengaruh yaitu kesehatan, dampak kesehatan yang ditimbulkan bukan hanya kesehatan secara fisik namun dapat memiliki efek serius pada kesehatan mental dan merujuk untuk munculnya keluhan stres kerja khususnya petugas kesehatan atau perawat. Kasus COVID-19 tidak bisa diprediksi, maka perlu adanya perkembangan ilmu kesehatan dalam penanganan COVID-19 khususnya pada perawat. Penelitian ini bertujuan untuk mengetahui Hubungan antara Beban Kerja dengan Stres Kerja pada Perawat Pelaksana di Ruang Isolasi COVID-19 Rumah Sakit Umum Daerah Kota Kotamobagu. Jenis penelitian kuantitatif dengan menggunakan metode analitik observasional dengan pendekatan studi potong lintang Cross-Sectional, dilaksanakan di RSUD Kota Kotamobagu pada bulan Agustus - Oktober tahun 2021. Sampel sebanyak 62 responden dengan menggunakan teknik pengambilan sampel yaitu total sampling. Instrumen dalam penelitian ini menggunakan kuesioner. Penelitian ini di ikuti oleh 62 responden dimana 53% berumur  28 tahun, mayoritas perempuan 71,6% dengan tingkat pendidikan D3 69,4% dan masa kerja  5 tahun 74%. Pada penelitian ini ditemukan 91,9% melaporkan mengalami stres ringan dan mempunyai beban kerja ringan 75,8%. Hasil penelitian ini menggunakan uji korelasi Somers’d. Hasil yang didapatkan dalam penelitian ini yaitu berdasarkan uji statistik diperoleh nilai korelasi koefisien sebesar 0,157 yang menunjukkan korelasi yang sangat lemah dengan nilai p = 0.153>0,05 artinya tidak ada hubungan antara beban kerja dengan stres kerja pada perawat pelaksana di ruang isolasi COVID-19 RSUD Kota Kotamobagu. Kesimpulan dalam penelitian ini bahwa beban kerja bukan satu-satunya faktor penting yang mempengaruhi stres kerja pada perawat pelaksana diruang isolasi COVID-19 RSUD Kota Kotamobagu. Saran untuk instansi rumah sakit agar bisa mengevaluasi faktor-faktor lain yang bisa menyebabkan stres pada perawat. Kata kunci: stres kerja, beban kerja, perawat pelaksana ruang isolasi COVID-19 ABSTRACTThe impact of the Coronavirus Disease of 2019 (COVID-19) outbreak has a serious impact on health workers. The most influential impact is health, the health impact caused not only physical health but can have a serious effect on mental health and refer to the emergence of complaints of work stress, especially health workers or nurses. COVID-19 cases cannot be predicted, so there needs to be the development of health science in handling COVID-19, especially in nurses. This study aims to find out the relationship between workload and work stress in the managing nurse in the isolation room of COVID-19 kotamobagu regional general hospital. This type of quantitative research using observational analytical methods with cross-sectional latitude cut study approach, was carried out at Kotamobagu Hospital in August - October 2021. A sample of 62 respondents using sampling techniques, namely total sampling. The instruments in the study used questionnaires. The study was followed by 62 respondents where 53% aged ≤ 28 years, the majority of women 71.6% with a D3 education level of 69.4% and a working period of ≤ 5 years 74%. In this study, 91.9% reported experiencing mild stress and having a light workload of 75.8%. The results of this study used the Somers'd correlation test. The results obtained in this study, based on statistical tests obtained a coefficient correlation value of 0.157 which showed a very weak correlation with a value of p = 0.153>0.05 means that there is no relationship between workload and work stress in the implementing nurse in the isolation room of COVID-19 Kotamobagu Hospital. The conclusion in this study that workload is not the only important factor that affects work stress in the implementing nurses in the isolation room of COVID-19 Kota Kotamobagu Hospital. Advice for hospital agencies to be able to evaluate other factors that can cause stress in nurses. Keywords: work stress, workload, COVID-19 isolation room managing nurse  

Creep, Relaxation and Viscosity Properties for Basic Fractional Models in Rheology

The purpose of this paper is twofold: from one side we provide a general survey to the viscoelastic models constructed via fractional calculus and from the other side we intend to analyze the basic fractional models as far as their creep, relaxation and viscosity properties are considered. The basic models are those that generalize via derivatives of fractional order the classical mechanical models characterized by two, three and four parameters, that we refer to as Kelvin-Voigt, Maxwell, Zener, anti-Zener and Burgers. For each fractional model we provide plots of the creep compliance, relaxation modulus and effective viscosity in non dimensional form in terms of a suitable time scale for different values of the order of fractional derivative. We also discuss the role of the order of fractional derivative in modifying the properties of the classical models.Comment: 41 pages, 8 figure

Core-mantle boundary deformations and J2 variations resulting from the 2004 Sumatra earthquake

The deformation at the core-mantle boundary produced by the 2004 Sumatra earthquake is investigated by means of a semi-analytic theoretical model of global coseismic and postseismic deformation, predicting a millimetric coseismic perturbation over a large portion of the core-mantle boundary. Spectral features of such deformations are analysed and discussed. The time-dependent postseismic evolution of the elliptical part of the gravity field (J2) is also computed for different asthenosphere viscosity models. Our results show that, for asthenospheric viscosities smaller than 10^18 Pa s, the postseismic J2 variation in the next years is expected to leave a detectable signal in geodetic observations.Comment: 14 pages, 8 figures, 1 table. It will appear in Geophysical Journal Internationa

DInSAR techniques for studying the October 23, 2011, Van earthquake (Turkey), and its relationship with neighboring structures

In October 2011 a strong earthquake hit the Van province, Eastern Turkey. Few days later (November 9th) an aftershock occurred few km southward. Finally in November 1976 another mainshock took place north of Van along the Caldiran fault. We have investigated the possible relations between 2011 mainshock and aftershock and the link with the 1976 earthquake. In order to complete the work SAR interferometry has been applied to measure surface displacements, while the fault geometries of the mainshock have been retrieved by a novel Neural Network approach. Moreover the CFF has been calculated to evaluate the role of 1976 earthquake in promoting the 2011 mainshock and, later on, the role of this latter respect to the aftershock in November 9th, 201

Testing Different Tectonic Models for the Source of the M w 6.5, 30 October 2016, Norcia Earthquake (Central Italy): A Youthful Normal Fault, or Negative Inversion of an Old Thrust?

We adopted a multidisciplinary approach to investigate the seismotectonic scenario of the 30 October 2016, Mw 6.5, Norcia earthquake, the largest shock of the 2016\u20132017 central Italy earthquake sequence. First, we used seismological and geodetic data to infer the dip of the main slip patch of the seismogenic fault that turned out to be rather low\u2010angle (~37\ub0). To evaluate whether this is an acceptable dip for the main seismogenic source, we modeled earthquake deformation using single\u2010 and multiple\u2010fault models deduced from aftershock pattern analyses. These models show that the coseismic deformation generated by the Norcia earthquake is coherent with slip along a rather shallow\u2010dipping plane. To understand the geological significance of this solution, we reconstructed the subsurface architecture of the epicentral area. As the available data are not robust enough to converge on a single fault model, we built three different models encompassing all major geological evidence and the associated uncertainties, including the tectonic style and the location of major d\ue9collement levels. In all models the structures derived from the contractional phase play a significant role: from controlling segmentation to partially reusing inherited faults, to fully reactivating in extension a regional thrust, geometrically compatible with the source of the Norcia earthquake. Based on our conclusions, some additional seismogenic sources falling in the eastern, external portions of the Apennines may coincide with inherited structures. This may be a common occurrence in this region of the chain, where the inception of extension is as recent as Middle\u2010Upper Pleistocene

GPS observations of coseismic deformation following the May 20 and 29, 2012, Emilia seismic events (northern Italy): data, analysis and preliminary models

In May-July 2012, a seismic sequence struck a broad area of the Po Plain Region in northern Italy. The sequence in- cluded two ML >5.5 mainshocks. The first one (ML 5.9) oc- curred near the city of Finale Emilia (ca. 30 km west of Ferrara) on May 20 at 02:03:53 (UTC), and the second (ML 5.8) occurred on May 29 at 7:00:03 (UTC), about 12 km south- west of the May 20 mainshock (Figure 1), near the city of Mirandola. The seismic sequence involved an area that ex- tended in an E-W direction for more than 50 km, and in- cluded seven ML ≥5.0 events and more than 2,300 ML >1.5 events (http://iside.rm.ingv.it). The focal mechanisms of the main events [Pondrelli et al. 2012, Scognamiglio et al. 2012, this volume] consistently showed compressional kinematics with E-W oriented reverse nodal planes. This sector of the Po Plain is known as a region charac- terized by slow deformation rates due to the northwards mo- tion of the northern Apennines fold-and-thrust belt, which is buried beneath the sedimentary cover of the Po Plain [Pi- cotti and Pazzaglia 2008, Toscani et al. 2009]. Early global po- sitioning system (GPS) measurements [Serpelloni et al. 2006] and the most recent updates [Devoti et al. 2011, Bennett et al. 2012] recognized that less than 2 mm/yr of SW-NE short- ening are accommodated across this sector of the Po Plain, in agreement with other present-day stress indicators [Mon- tone et al. 2012] and known active faults [Basili et al. 2008]. In the present study, we describe the GPS data used to study the coseismic deformation related to the May 20 and 29 mainshocks, and provide preliminary models of the two seismic sources, as inverted from consensus GPS coseismic deformation fields