Датчик угла поворота генераторного типа с элементом на поверхностных акустических волнах

Разработан интеллектуализированный датчик угла поворота с акустоэлектронным элементом оригинальной конструкции, выполняющим роль линии задержки.Представлено результати розробки інтелектуалізованого датчика кута повороту з елементом на поверхневих акустичних хвилях (ПАХ). Описано структурну схему сенсора генераторного типу, в якому елемент на ПАХ грає роль відповідної лінії затримки. Представлено основні характеристики датчика, показано область його застосування.·The results of intellectualized angle of rotation sensor with an element on the surface acoustic waves (SAW) development are presented. The generating type sensor block diagram, in which the element on SAW plays a role of the appropriate line of a delay is described. The sensor basic characteristics are given and the area of its application are shown

Reflection imaging of complex geology in a crystalline environment using virtual-source seismology : case study from the Kylylahti polymetallic mine, Finland

For the first time, we apply a full-scale 3D seismic virtual-source survey (VSS) for the purpose of near-mine mineral exploration. The data were acquired directly above the Kylylahti underground mine in Finland. Recorded ambient noise (AN) data are characterized using power spectral density (PSD) and beamforming. Data have the most energy at frequencies 25-90 Hz, and arrivals with velocities higher than 4km s(-1) have a wide range of azimuths. Based on the PSD and beamforming results, we created 10 d subset of AN recordings that were dominated by multi-azimuth high-velocity arrivals. We use an illumination diagnosis technique and location procedure to show that the AN recordings associated with high apparent velocities are related to body-wave events. Next, we produce 994 virtual-source gathers by applying seismic interferometry processing by cross-correlating AN at all receivers, resulting in full 3D VSS. We apply standard 3D time-domain reflection seismic data processing and imaging using both a selectively stacked subset and full passive data, and we validate the results against a pre-existing detailed geological information and 3D active-source survey data processed in the same way as the passive data. The resulting post-stack migrated sections show agreement of reflections between the passive and active data and indicate that VSS provides images where the active-source data are not available due to terrain restrictions. We conclude that while the all-noise approach provides some higher-quality reflections related to the inner geological contacts within the target formation and the general dipping trend of the formation, the selected subset is most efficient in resolving the base of formation.Peer reviewe

Application of the Marchenko method to a land seismic dataset

The Marchenko method is capable of estimating Green's functions between the surface of the Earth and arbitrary locations in the subsurface. This method enables the isolation of the response of a specific layer or package of layers, free from the influence of the overburden and underburden. In this study, we apply the Marchenko-based isolation technique to land S-wave seismic data acquired in the Groningen province, the Netherlands, even though applying the Marchenko method to land data is very challenging. We apply the technique for three scenarios: overburden elimination, underburden elimination, and combined elimination of the overburden and underburden. Our results indicate that this approach partly enhances the resolution of reflections and eliminates internal multiples. These enhanced reflections can be utilized for imaging and monitoring applications, where we expect improved results due to the elimination of the overburden and underburden.Comment: 10 pages, 7 figure

Passive seismic imaging in the presence of white noise sources: numerical simulations

this paper we show by numerical simulations that the received reflection response strongly depends on the whiteness of the sources. Reflectors present beneath the noise sources cause some ghost events to appear. Random distribution of the noise sources weakens these ghost reflection

Azimuthal Anisotropy of the Megaregolith at the Apollo 14 Landing Site

The characterization of the megaregolith on the Moon has been investigated in various ways including analysis of lunar meteorites, remote sensing of mineralogy and gravity, and deriving a seismic velocity profile. In this study, we propose a method for analyzing azimuthal anisotropy of the megaregolith. We call this method deep-moonquake seismic interferometry applied to S-wave coda (DMSI-S). DMSI-S can turn the records of deep moonquakes into recordings from virtual active sources. The retrieved virtual sources coincide with the station positions, and thus, we obtain virtual zero-offset (pulse-echo) measurements. DMSI-S is applied to seven clusters of deep moonquakes recorded at the Apollo 14 landing site, resulting in virtual zero-offset measurements at the Apollo station 14. We use the S-wave recordings retrieved from DMSI-S to analyze azimuthal anisotropy. We find weak anisotropy at the layer where the megaregolith is assumed to be present. We interpret our result to show that the megaregolith at this site is characterized by a layer (or layers) of impact material, following the Imbrium impact, with internal alignment of the crushed material

From Reflection Data To Transmission Coda

this paper this relation is used to calculate the transmission coda from reflection data measured at the surface. The transmission response is represented by a generalized propagator consisting of a primary propagator and a coda operator. Using this representation it is possible to solve the implicit relation for the coda operator, using an eigenvalue decomposition on the correlation of the reflection response. The calculated coda response may be used in seismic reflection imaging to obtain an image in which the internal multiple scattering effects are suppressed. A simple example for the estimation of the transmission coda illustrates the discussed procedur