Magnetic Field and Electron Density Data Analysis from Swarm Satellites Searching for Ionospheric Effects by Great Earthquakes: 12 Case Studies from 2014 to 2016

We analyse Swarm satellite magnetic field and electron density data one month before and one month after 12 strong earthquakes that have occurred in the first 2.5 years of Swarm satellite mission lifetime in the Mediterranean region (magnitude M6.1+) or in the rest of the world (M6.7+). The search for anomalies was limited to the area centred at each earthquake epicentre and bounded by a circle that scales with magnitude according to the Dobrovolsky’s radius. We define the magnetic and electron density anomalies statistically in terms of specific thresholds with respect to the same statistical quantity along the whole residual satellite track (|geomagnetic latitude| ≤ 50°, quiet geomagnetic conditions). Once normalized by the analysed satellite tracks, the anomalies associated to all earthquakes resemble a linear dependence with earthquake magnitude, so supporting the statistical correlation with earthquakes and excluding a relationship by chance.PublishedID 3711A. Geomagnetismo e PaleomagnetismoJCR Journa

RICORS2040 : The need for collaborative research in chronic kidney disease

Chronic kidney disease (CKD) is a silent and poorly known killer. The current concept of CKD is relatively young and uptake by the public, physicians and health authorities is not widespread. Physicians still confuse CKD with chronic kidney insufficiency or failure. For the wider public and health authorities, CKD evokes kidney replacement therapy (KRT). In Spain, the prevalence of KRT is 0.13%. Thus health authorities may consider CKD a non-issue: very few persons eventually need KRT and, for those in whom kidneys fail, the problem is 'solved' by dialysis or kidney transplantation. However, KRT is the tip of the iceberg in the burden of CKD. The main burden of CKD is accelerated ageing and premature death. The cut-off points for kidney function and kidney damage indexes that define CKD also mark an increased risk for all-cause premature death. CKD is the most prevalent risk factor for lethal coronavirus disease 2019 (COVID-19) and the factor that most increases the risk of death in COVID-19, after old age. Men and women undergoing KRT still have an annual mortality that is 10- to 100-fold higher than similar-age peers, and life expectancy is shortened by ~40 years for young persons on dialysis and by 15 years for young persons with a functioning kidney graft. CKD is expected to become the fifth greatest global cause of death by 2040 and the second greatest cause of death in Spain before the end of the century, a time when one in four Spaniards will have CKD. However, by 2022, CKD will become the only top-15 global predicted cause of death that is not supported by a dedicated well-funded Centres for Biomedical Research (CIBER) network structure in Spain. Realizing the underestimation of the CKD burden of disease by health authorities, the Decade of the Kidney initiative for 2020-2030 was launched by the American Association of Kidney Patients and the European Kidney Health Alliance. Leading Spanish kidney researchers grouped in the kidney collaborative research network Red de Investigación Renal have now applied for the Redes de Investigación Cooperativa Orientadas a Resultados en Salud (RICORS) call for collaborative research in Spain with the support of the Spanish Society of Nephrology, Federación Nacional de Asociaciones para la Lucha Contra las Enfermedades del Riñón and ONT: RICORS2040 aims to prevent the dire predictions for the global 2040 burden of CKD from becoming true

Modeling geomagnetic spikes: the Levantine Iron Age anomaly

Abstract The Levantine Iron Age anomaly (LIAA) is a regional short-decadal geomagnetic strength field variation located at the Levantine region characterized by high intensities with maximum virtual axial dipole moments around 190 ZAm2. It has been constrained by archeomagnetic data coming from Eastern Europe and Western Asia between 1050 and 700 BC. The LIAA can be related to a fast and spatially localized geomagnetic positive anomaly (spike) at the Earth’s surface. In this study, we model the LIAA by using a Fisher–von Mises function that fits the most recent archeomagnetic intensity database in the region. A spherical harmonic analysis is implemented for this spike function to perturb a base model in order to build a global reconstruction (perturbed-model) that reproduces the spatial and temporal characteristics of the LIAA. Our results show the importance of harmonic degrees from n = 3–4 to n = 20 to reconstruct the anomaly extension suggested by the database. Two maxima linked with the LIAA are reproduced by our global perturbed-model at the Levantine region at 950 BC and 750 BC. A third maxima in intensity around 500 BC is also observed, affecting the whole Europe. Graphical Abstrac

Statistical analysis of the oceanic magnetic anomaly data

The study of the statistical properties of ocean magnetic anomalies could be very important to obtain new understanding on plate tectonics, especially about the past properties of the lithospheric oceanic plates. Here we analyse in terms of statistical distributions the ocean magnetic anomaly data at the global scale covering the crustal oceanic ages from the present to 180 Ma. Our results show that the marine magnetic anomaly data follow the Laplace statistical distribution. This behaviour is observed at global scale and for any time interval within the last 180 Ma. In addition, the statistical parameters of the Laplace distribution are used to define some properties of the crustal oceanic magnetic field, focusing our investigation on the Cretaceous Normal Superchron. Finally, we also provide a physical explanation of this statistical distribution of marine magnetic anomaly data using a test with synthetic data

A regional archeomagnetic model for Europe for the last 3000 years, SCHA.DIF.3K: Applications to archeomagnetic dating

International audienceThe available European database of archeomagnetic field values and instrumental data has been used to produce a regional model for the geomagnetic field in Europe for the last 3000 years (from 1000 B.C. to 1900 A.D., connecting with the epoch covered by the IGRF models). This new model, SCHA.DIF.3K, constitutes an improvement with respect to the previous regional archeomagnetic model SCHA.DI.00-F, which used relocated values and was only valid for the last 2000 years. The new model has been obtained by least sums of absolute deviation inversion of paleomagnetic data using spherical cap harmonics for the spatial representation of the field and sliding windows in time. An algorithm has been developed to jointly model the three archeomagnetic elements declination, inclination, and intensity. The resulting model provides the direction and intensity of the Earth's magnetic field over the European continent, northern Africa, and western Asia for the last 3000 years. The fit to the European archeomagnetic database is more accurate than that provided by global archeomagnetic models. In addition, this model represents a step forward in archeomagnetic dating studies (since the relocation error is avoided) and can also be used to study the rapid changes of the geomagnetic field (archeomagnetic jerks) that have been recently proposed

Paleomagnetic study of an historical lava flow from the Llaima volcano, Chile

The understanding of the paleosecular variations (PSV) of the geomagnetic field in South America is still biased by the scarcity of data. Especially, the recent geomagnetic PSV is characterized by the large growth of the South Atlantic Magnetic Anomaly (SAMA) during the last centuries, first documented by the geomagnetic model gufm1 (Jackson et al., 2000). A large amount of data is required to understand the time and geographic distribution of this primary feature, and the Andean Pleistocene and Holocene volcanoes are an excellent recorder of instant local changes in SV. Here we present a preliminary study from 18 paleomagnetic samples collected during 2015 on what it was supposed to be the 1750 or the 1957–58 AD lava flow on the Llaima Volcano (38.692° S; 71.729° W), one of the most active centers of the Chilean Andes, in the Southern Volcanic Zone. A detailed paleomagnetic study was performed in order to recover the Declination and Inclination of the geomagnetic field, obtain the paleointensity and define the magnetic mineralogy. AF demagnetization until 1 T yielded an average vector at Dec/Inc 2.3°/-33.1° with α95 of 2.4°. This direction is carried by titanomagnetite grains with 40–45% ulvospinel as revealed by thermomagnetic curves. Paleointensity estimates were obtained following the IZZI-Thellier protocol. Seven specimens from 5 samples provided reliable results (success rate of 35%), giving an average paleointensity for these specimens of 30.88 ± 2.39 μT. The full magnetic vector obtained here was compared to archaeomagnetic reference curves and the IGRF suggest that the lava flow has the age of 1957–58 AD.Peer reviewe

Revisiting the connection between the past geomagnetic field and the radionuclide production rate. A04-A05-Oral-995

Trabajo presentado en IAPSO-IAMAS-IAGA Assembly, celebrada en Cape Town (Sudáfrica), del 27 de agosto al 1 de septiembre de 2017The production rates of cosmogenic isotopes, such as 14C and 10Be, are directly modulated by the strength of the Solar and Earth magnetic fields. Changes in the isotope production rate during the Holocene are estimated mainly from isotopic sampling in tree and ice cores, while the past evolution of the geomagnetic field can be recovered from well‐dated rock samples containing magnetic minerals than can be used to obtain the so‐called paleomagnetic data. However, no indirect measurements provide the past solar activity. Estimates of solar forcing play an important role in understanding paleoclimatic temperature reconstructions and as boundary conditions in simulations with climate models due to its influence to modify the energy balance of the Earth. Nowadays, different studies consider that both magnetic fields affect the production rate at two different timescales: the long‐term modulation is associated to changes in the geomagnetic field and the shorter variations to the past solar activity. However, the most recent palaeomagnetic reconstructions developed during the last years provide a new picture with higher temporal resolution of the past variations of the strength of the Earth’s magnetic field. In this work, we revisit the connection between the past evolution of the Earth’s magnetic field and the production rates of 14C and 10Be for the Holocene by means of the more complete paleomagnetic database and the most recent geomagnetic reconstructions.Peer reviewe

Centennial modulation of radionuclide production by the past Earth’s magnetic field

Trabajo presentado en la X Reunión de la Comisión de Paleomagnetismo de la Sociedad Geológica de España, celebrada del 14 al 17 de septiembre de 2017 en el valle del río Grío, Zaragoza (España)The rate of production of cosmogenic isotopes, such as 14C or 10Be, plays an important role in our understanding of the solar-terrestrial relationship since radionuclides records stored in polar ice cores and tree rings offer the unique way to reconstruct changes in the solar total irradiance during the Holocene (see Usoskin, 2017, for a review). To accurately determine past solar activity, the effect of the variability of the geomagnetic field upon the production of cosmogenic radionuclides needs to be properly considered since the Earth´s magnetic field greatly modulates the rate of isotope production in the atmosphere. Up to now, it has been assumed that the long-term time variation of isotope production rate is mainly modulated by changes in the geomagnetic field whereas the solar magnetic field dominates shorter time wavelengths (Snowball and Muscheler, 2007; Usoskin et al., 2016). Here we reanalyse this assumption by demonstrating that the geomagnetic field also exerts a strong modulation of high-frequency (periods of ∼800 yr) atmospheric radiocarbon production rates that are currently being wrongly associated to solar activity. Specifically, we identify for the first time a clear and robust coherence, in terms of amplitude and phases, between the production rate curve directly derived from the geomagnetic field reconstruction derived from the SHA.DIF.14k global model (PavónCarrasco et al., 2014) and the original isotope production curve for the Holocene (Steinhilber et al., 2012). Our results provide a new vision of the mechanisms causing the observed isotope production variability and, hence, are crucial to re-evaluate past solar forcing and use it as a benchmark to test links between climate and total solar irradiance in the next generation of climate models.Peer reviewe

Multi-centennial fluctuations of radionuclide production rates are modulated by the Earth’s magnetic field

Trabajo presentado en el AGU (American Geophysical Union) Fall Meeting: Advancing Earth and Space Science, celebrado en New Orleans. (Estados Unidos), del 11 al 15 de diciembre de 2017The production of 14C and 10Be cosmogenic isotopes offer a unique way to reconstruct solar activity during the Holocene. This production is influenced by both solar and Earth magnetic fields and thus their combined effect needs to be disentangled to reconstruct past solar irradiance. Nowadays, it assumes that the long-term variations of production is modulated by the geomagnetic field and the solar field dominates shorter wavelengths. In this process, the effect of the wandering of the Earth’s magnetic poles is considered negligible. Here we revaluate these assumptions and demonstrate that the geomagnetic field exerts a strong modulation of multi-centennial to millennial wavelengths (periods of 800 and 2200 yr) that have so far been wrongly assigned to solar activity. Moreover, we demonstrate that the motion of the Earth’s magnetic poles produce differences of up to 35% in production at mid-latitudes. The results are supported by the identification, for the first time, of robust coherence between the production derived from geomagnetic reconstructions and that from natural archives. Our results imply a revision of the past solar forcing, with implications both for the assessment of solar-climate relationships and for the forcing conditions used in the present and future generation of paleoclimate models.Peer reviewe