Ocean loading effects from tidal tilt observations in Lanzarote Island

Comunicación presntada a la 3ª Asamblea Hispano-Portuguesa de Geodesia y Geofísica = 3ª Assembleia Luso-Espanhola de Geodesia e Geofisica, celebrada en Valencia entre el 4 y el 8 de febrero de 2002.Since 1995 two short base-length horizontal pendulums are continuously recording at the station Cueva de los Verdes (Geodynamics laboratory of Lanzarote). Both tilt-meters are modified from the classical Ostrovsky pendulums and are adapted to the local features of the station. The tilt-meters have a working range of measurements of +-20seconds of arc and can resolve up to one second of arc. Such technical properties allow determining the precise tilt response to Earth tides. The tidal tilt models obtained show an important influence from ocean tides. Thus, the estimated amplitude for the main harmonic constituents is of some 4-5 times larger than values measured at continental stations. In this work, the ocean loading and attraction effect, which are computed from global ocean tidal models supplemented with precise regional and local ones will be evaluated. Hence, tidal tilt observations can be corrected from this effect.Peer reviewe

Geophysical Observatory in Kamchatka region for monitoring of phenomena connected with seismic activity

Regular monitoring of some geophysical parameters in association with seismicity has been carried out since last year at the Japan-Russian Complex Geophysical Observatory in the Kamchatka region. This observatory was organized in connection with the ISTC project in Russia and was motivated by the results of the FRONTIER/RIKEN and FRONTIER/NASDA research projects in Japan. The main purpose of the observations is to investigate the electromagnetic and acoustic phenomena induced by the lithosphere processes (especially by seismic activity). The seismicity of the Kamchatka area is analyzed and a description of the observatory equipment is presented. At present, the activity of the observatory includes the seismic (frequency range &#x2206;F = 0.5 – 40 Hz) and meteorological recordings, together with seismo-acoustic (&#x2206;F = 30 – 1000 Hz) and electromagnetic observations: three-component magnetic ULF variations ( &#x2206;F = 0.003 – 30 Hz), three-component electric potential variations ( &#x2206;F <u><</u> 1.0 Hz), and VLF transmitter’s signal perturbations ( &#x2206;F ~ 10 – 40 kHz)

Study of electromagnetic emissions associated with seismic activity in Kamchatka region

International audienceA review of data processing of electromagnetic emission observation collected at the Complex Geophysical Observatory Karimshino (Kamchatka peninsula) during the first 5 months (July?November, 2000) of its operation is given. The main goal of this study addresses the detection of the phenomena associated with Kamchatka seismic activity. The following observations have been conducted at CGO: variations of ULF/ELF magnetic field, geoelectric potentials (telluric currents), and VLF signals from navigation radio transmitters. The methods of data processing of these observations are discussed. The examples of the first experimental results are presented

Imaging the volcanic structures beneath Gran Canaria Island using new gravity data

From a new gravity data set that covers homogeneously the whole surface of Gran Canaria (Canary Islands, Spain) and marine gravity data in the nearest offshore, we have obtained a Bouguer anomaly gravity map of the island which improves the previous ones. Using these gravity anomalies, we have applied a gravity inversion approach to investigate the structures beneath the surface of Gran Canaria Island and derive a 3D gravity sources model. The geometry of structures with anomalous density values is constrained up to a depth of approximately 20,000 m below the sea level. The interpretation of the density model identified structures related to the different volcanic stages of Gran Canaria. Several deep-rooted high-density structures represent the intrusive bodies emplaced in the early formation of Gran Canaria and the magma plumbing system of the Miocene volcanic edifices. A low-density body in the center of the island may be associated with the syenitic core of the felsic central volcanic edifice (Tejeda Caldera). Shallow low-density structures identified fractures which acted as feeder dikes of monogenetic volcanoes during the rejuvenated stage. Finally, the NW-SE rift, which is the most important volcano-tectonic structure of Gran Canaria, has a characteristic gravimetric signature and represents a long-lived extensional fracture zone that has controlled the volcanic activity at least since the Miocene

Цитомегаловирусная инфекция и врожденная патология сердца у детей

Congenital heart defects account for about 30% of all anomaly of development in children. Cytomegalovirus infection suffered by a woman during pregnancy claims one of the leading places among teratogenic factors.Aim: to study clinical and pathogenetic features of congenital heart diseases in children with active cytomegalovirus infection.Materials and methods: the survey included 240 children with congenital heart defects under 1 years old. The diagnosis was verified by enzyme immunoassay with detection of immunoglobulins of classes M and G to cytomegalovirus and by polymerase chain reaction, the material for which was blood and urine.Results. For congenital heart defects with the active forms of cytomegalovirus infection is characterized by a higher frequency of combined defects and the development of critical states. Children with cytomegalovirus infection in 40% suffered intrauterine myocarditis of cytomegalovirus etiology, which weighed the course of the underlying disease. The features characteristic of IUI was determined much more often (in the analysis of the noncardiac symptoms). Specific therapy of active forms of cytomegalovirus infection in children before surgery for correction of congenital heart defects has reduced the likelihood of postoperative complications.Summary. Cytomegalovirus infection has a direct teratogenic effect and can provoke the development of congenital heart defects. In addition, the virus has a cardiotropic and immune-mediated effect on the myocardium. This leads to the development of intrauterine myocarditis, which aggravates the course of the disease. The specific treatment of active forms of cytomegalovirus infection in children before surgery for the correction of congenital heart defects, reduces the likelihood of postoperative complications.Врожденные пороки сердца составляют около 30% от всех аномалий развития у детей. Среди тератогенной группы причин на одно из ведущих мест претендует цитомегаловирусная инфекция, перенесенная женщиной во время беременности.Цель: изучить клинико-патогенетические особенности врожденных пороков сердца у детей с активной цитомегаловирусной инфекцией.Материалы и методы: обследовано 240 детей в возрасте до 1 года с врожденными пороками сердца. Верификацию цитомегаловирусной инфекции проводили методом иммуноферментного анализа с обнаружением иммуноглобулинов классов М и G к цитомегаловирусу и методом полимеразной цепной реакции, материалом для которой служили кровь, моча.Результаты. Для врожденных пороков сердца на фоне активных форм цитомегаловирусной инфекции характерна более высокая частота комбинированных пороков, развития критических состояний. У 40% детей с цитомегаловирусной инфекцией отмечался внутриутробный миокардит цитомегаловирусной этиологии, что утяжеляло течение основного заболевания. При анализе экстракардиальных симптомов значительно чаще определялись признаки, характерные для врожденных инфекций. Проведение специфической терапии активных форм цитомегаловирусной инфекции у детей перед оперативным вмешательством по поводу коррекции врожденных пороков сердца позволило снизить вероятность развития постоперационных осложнений. Заключение. Цитомегаловирусная инфекция, обладая прямым тератогенным действием, может сама спровоцировать развитие врожденных пороков сердца. Кроме того, способность вируса оказывать кардиотропное и иммуноопосредованное воздействие на миокард с развитием внутриутробного миокардита утяжеляет течение заболевания. Проведение специфической терапии активных форм цитомегаловирусной инфекции у детей перед оперативным вмешательством по поводу коррекции врожденных пороков сердца позволяет снизить вероятность развития постоперационных осложнений

Application of Surface wave methods for seismic site characterization

Surface-wave dispersion analysis is widely used in geophysics to infer a shear wave velocity model of the subsoil for a wide variety of applications. A shear-wave velocity model is obtained from the solution of an inverse problem based on the surface wave dispersive propagation in vertically heterogeneous media. The analysis can be based either on active source measurements or on seismic noise recordings. This paper discusses the most typical choices for collection and interpretation of experimental data, providing a state of the art on the different steps involved in surface wave surveys. In particular, the different strategies for processing experimental data and to solve the inverse problem are presented, along with their advantages and disadvantages. Also, some issues related to the characteristics of passive surface wave data and their use in H/V spectral ratio technique are discussed as additional information to be used independently or in conjunction with dispersion analysis. Finally, some recommendations for the use of surface wave methods are presented, while also outlining future trends in the research of this topic