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Date submitted2018-11-10
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Date accepted2019-01-17
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Date published2019-04-23
AMT soundings in the dead band within the Chukotka region (Russian Far East)
The article analyzes the amplitude spectra of audio magnetotelluric sounding (AMTs) data. Particular attention is focused on the frequency range from 1 to 5 kHz, which is called dead band. We analyzed the data of base stations used in the fieldwork during the summer and autumn seasons in 2013, 2014, and 2017. The area of work is located in the Chukotka Autonomous Area beyond the Arctic Circle. Previous researchers noted that a reliable signal in the dead band can only be obtained at nighttime. The authors of the article found that in Chukotka region in the daytime against the minimum signal within the dead band there is a local maximum at a frequency of 2.4 kHz. When registering a field for more than 3 hours during daytime, in most cases, it is possible to restore the frequencies of 2.2 and 2.6 kHz. These frequencies are reliable benchmarks, allowing in some cases to restore the AMT curve using the correlation between amplitude and phase. We have proposed ways to improve data quality in the dead band when measured during the daytime.
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Date submitted1952-07-25
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Date accepted1952-09-12
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Date published1953-01-01
Types of quartz veins of the Urals and their crystal content
- Authors:
- A. E. Karyakin
Three systems of jointing cracks predominate in the rocks of the crystal-bearing strip of the Northern Urals: concordant, intersecting and transverse. Almost all crystal-bearing quartz veins of the Northern Urals are confined to these cracks. Among the quartz veins of the Northern Urals, the first two types are most common. Transverse quartz veins are less common. It should be noted that the division of quartz veins into the listed types is conditional, since they are all of the same age, genetically related and fulfill a system of three interconnected tectonic cracks