The Infrasound Network of Ukraine
Authors: Liashchuk Oleksandr , Kariahin Yevhenii , Kolesnykov Leonid , Andrushchenko Yurii , Tolchonov Ivan , Poikhalo Anatolii 
Published: March 2020

&lt;p&gt;Geophysical monitoring observations in Ukraine are performed by the Main Center of Special Monitoring (MCSM), which is a part of the National Space Facilities Control and Test Center, State Space Agency of Ukraine. The MCSM ensures the implementation of the Ukrainian international obligations within the CTBT. It also provides prompt&amp;#160;warning and response to emergencies, based on geophysical monitoring results, and runs continuous complex geophysical observations for scientific purposes.&amp;#160;&lt;/p&gt;&lt;p&gt;Infrasound monitoring is one of the types of geophysical monitoring, performed by the MCSM. The infrasound network of Ukraine consists of three observatories, which include mini-arrays of microbarographs (3-4 microbarographs). Standard geometric configuration for an array is a triangle. The aperture of arrays ranges between 200 and 900 meters. There are also three separate observation points, with the only one microbarograph in each. The spacing between these points is hundreds of kilometers. The entire infrasound network is in North-Western Ukraine. One more Ukrainian observatory based in the Antarctic, the Vernadsky Research Base. All microbarographs equipped with wind-protection systems. Microbarographs from the Soviet K-304 acoustic station (0.03-10 Hz, 100 Pa) are currently used in combination with a 4-channel 24-bit digitizer. Besides, Ukraine has created new models of microbarographs with similar technical characteristics.&amp;#160;The scheduled&amp;#160;upgrade&amp;#160;of the sensors is currently underway.&amp;#160;There are also plans for installing infrasound arrays in the Eastern and Southern Ukraine. Furthermore, for assessing the possibility of recording large-scale processes in the atmosphere, the pilot plant of the microbarographs on the seismic array nodes PS45 is scheduled for this year. In this case, the distance between the elements of the infrasound array will be around 3-4 kilometers.&lt;/p&gt;&lt;p&gt;Previously mentioned infrasound arrays recorded a wide range of technogenic and natural phenomena, which could be of interest to the scientific community. Among the technogenic ones are explosions at the military arsenals, gas pipeline explosions, plane crashes, and an enormous number of mining blasts. Infrasound signals have also been caused by natural events such as earthquakes, tsunamis, avalanches, hurricanes, thunderstorms, meteorite explosions.&lt;/p&gt;&lt;p&gt;Infrasound data is transmitted to the NDC for processing and storing, using the SeedLink protocol. Registration of the events and events-bulletin is done by an operational on-duty team 24/7. The government authorities responsible for safety are notified immediately in case of emergency events. Data processing realized by using Geotool and WinPMCC, as well as the own software. It also used data from the foreign infrasound arrays for analysis. The Memorandum with the Central and East European Infrasound Network was signed in 2019. For optimizing the on-duty team's, geophysicists-analysts', and experts' work, processing of the infrasound data in the MCSM, as an experiment, has been transferred to the internal MCSM cloud platform. It facilitated access to the information, provided equal opportunities for the processing, and allowed involving experts from other institutions.&amp;#160;&lt;/p&gt;&lt;p&gt;In the future, all of the above allows actively using the infrasound network of Ukraine for running global and regional monitoring and doing researches on the atmosphere and climate.&lt;/p&gt;