Activities Of The Yakutsk Geophysical Observatory (Cosmic Ray Laboratory) In 1928–1962

The relevance of the research topic is related to the generalization of the Soviet experience in formation and development of cosmophysical research in Yakutia over several decades, from the activities of weather stations to the creation of the Institute of Cosmophysical Research and Aeronomy of the Yakutsk Branch of the USSR Academy of Sciences. The formation of the network of 23 stationary meteorological and upper-air stations and the Geophysical Observatory is disclosed. The first stage of the activity of these institutions was identified as of high practical importance in the development of aviation, gold mining industry on Aldan and Amur-Yakutsk highway construction.The second stage was characteristic by innovative developments of Yakut scientists as semiconductor devices for artificial Earth satellites, cameras for shooting auroras, and an ionization camera for continuous registration of cosmic rays, that received worldwide recognition. Study of radiation situation in near-Earth space during solar flares and high-altitude thermonuclear explosions testified, that Yakutia contributed to increasing of the country's defense capability. Particular attention is paid to the activities of the station on Bolshoy Lyakhovsky Island of the Novosibirsk Islands, which served Arctic aviation flights and coastal navigation along the Northern Sea Route.

THE LASER TECHNOLOGY FOR EARTHQUAKE'S FORECAST AND FOR DIFFERENT APPROACHES OF SEISMIC HAZARD ASSESSMENT

Historically, the first laser-deformograph was developed by group of Geophysical Observatory of the Tavria National University named after I. Vernadsky (formerly Simferopol State University named after M.V. Frunze) and started to work in 1981. This laser complex allowed to carry out the measurements of the Earth’s long time deformation. The measuring volume of the observatory was located in an adit (depth of about 20 meters), which connects the right rangefinder post with the main battery structure and has a series of sealed baffles (doors, hatches) that isolate it from external influences. In the capacity of the main tools for studying oscillatory processes in the environment, the Geophysical Observatory used two-beam laser interferometers of the Michelson type with spaced beams, which have very high metrological characteristics and use the wavelength of a frequency-stabilized laser as a reference. Engineering support of the interferometric complexes’ functioning in the Geophysical Observatory was carried out by: F.N. Pankov, A.V. Buklersky, V.I. Tokarev [5].

The Geophysical Observatory in Sodankylä, Finland – past and present

After a preface, we will first try to depict the history of the Geophysical Observatory in Sodankylä (SGO) by referring to the personalities who have run and have shaped the observatory. Thereafter, we describe the history from a technical point of view, i.e., what the measurements were, and which instruments were primarily used at the observatory. We will also refer to present operational forms and techniques. We start with the very first systematic meteorological and geophysical observations made in Finland and end by referring to the involvement in ongoing international scientific programs.

Construction of a Geophysical Observatory in Fürstenfeldbruck in Germany

The article deals with the construction of a geophysical observatory in the town of Fürstenfeldbruck, Bavaria, Germany. The observatory is being built for the Technical university in Munich. The main function of the observatory is to measure changes in the Earth ́s spin rate or, its axes deviations etc., which can occur with physical impulses in a form of, for example, an earthquake or nuclear explosion etc. Measuring such physical phenomena is important and the data is used to adjust navigation of satellites orbiting the Earth. As there were installed unique measuring tools in the building, the construction materials and building process itself has had to be carefully chosen and though through. The observatory is placed underground and has shape of a tetrahedron. The top of the construction is oriented in direction to the Earth ́s centre. To secure the pit the sprayed shotcrete was used and reinforced with AR Glass. To anchor the pit horizontally they also used the AR Glass. After finishing the pit, the central shaft was built and situated vertically from the top of the tetrahedron in direction to the Earth ́s surface and to the top of the tetrahedron base. Under a layer of concrete, there is a PE HD pipe DN 630 in every wall to connect the tetrahedron top with the base tops. There are several concrete shafts situated in each top tetrahedron base and also, at half of the span between the tetrahedron base tops. All these concrete shafts on the ground are interconnected by plinth beam with one another. The plinth beam contains three PE HD pipes DN 140. This type of construction was chosen as there is laser circling in the tetrahedron base, its top, and between tetrahedron top and base. In every shaft there is installed a measuring instrument, which is very sensible when in contact with steel parts. The sensibility to steel was a reason for employing only glass reinforcement GFK in every concrete part of this construction.

Data management at the Oulu cosmic ray station

With the recent electronics upgrade of Antarctic neutron monitors (NMs) DOMC and DOMB in 2019, the Oulu cosmic ray station (Sodankylä Geophysical Observatory, Finland) receives a significantly larger amount of data than before. This has led to a need for an important upgrade of the configuration of servers working at the station. The new configuration has three types of servers: a web-server, a datamaster server and data acquisition machines. The web-server provides a user interface for services of the station: the main website, the GLE database and other services. The datamaster is the main server, which stores all data in raw files and a database. Data acquisition machines are computers that directly receive data from the instruments and send the files farther to the datamaster server. This work describes technical details of the cosmic ray station setup providing reliable and secure data acquisition, handling and publication.

VLBI measurement of the vector baseline between geodetic antennas at Kokee Park Geophysical Observatory, Hawaii

We measured the components of the 31-m-long vector between the two very-long-baseline interferometry (VLBI) antennas at the Kokee Park Geophysical Observatory (KPGO), Hawaii, with approximately 1 mm precision using phase delay observables from dedicated VLBI observations in 2016 and 2018. The two KPGO antennas are the 20 m legacy VLBI antenna and the 12 m VLBI Global Observing System (VGOS) antenna. Independent estimates of the vector between the two antennas were obtained by the National Geodetic Survey (NGS) using standard optical surveys in 2015 and 2018. The uncertainties of the latter survey were 0.3 and 0.7 mm in the horizontal and vertical components of the baseline, respectively. We applied corrections to the measured positions for the varying thermal deformation of the antennas on the different days of the VLBI and survey measurements, which can amount to 1 mm, bringing all results to a common reference temperature. The difference between the VLBI and survey results are 0.2 ± 0.4 mm, −1.3 ± 0.4 mm, and 0.8 ± 0.8 mm in the East, North, and Up topocentric components, respectively. We also estimate that the Up component of the baseline may suffer from systematic errors due to gravitational deformation and uncalibrated instrumental delay variations at the 20 m antenna that may reach ± 10 and −2 mm, respectively, resulting in an accuracy uncertainty on the order of 10 mm for the relative heights of the antennas. Furthermore, possible tilting of the 12 m antenna increases the uncertainties in the differences in the horizontal components to 1.0 mm. These results bring into focus the importance of (1) correcting to a common reference temperature the measurements of the reference points of all geodetic instruments within a site, (2) obtaining measurements of the gravitational deformation of all antennas, and (3) monitoring local motions of the geodetic instruments. These results have significant implications for the accuracy of global reference frames that require accurate local ties between geodetic instruments, such as the International Terrestrial Reference Frame (ITRF).