University of Oulu

Afonin, Nikita; Kozlovskaya, Elena; Nevalainen, Jouni; Narkilahti, Janne (2019) Improving the quality of empirical Green's functions, obtained by cross-correlation of high-frequency ambient seismic noise. Solid Earth, 10, 1621–1634, https://doi.org/10.5194/se-10-1621-2019

Improving the quality of empirical Green's functions, obtained by cross-correlation of high-frequency ambient seismic noise

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Author: Afonin, Nikita1,2; Kozlovskaya, Elena1,3; Nevalainen, Jouni1,4;
Organizations: 1Oulu Mining School, P.O. Box 3000, 90014 University of Oulu, Oulu, Finland
2N. Laverov Federal Centre for the Integrated Arctic Research RAS, Arkhangelsk, Russia
3Geological Survey of Finland, P.O. Box 96, 02151, Espoo, Finland
4Sodankylä Geophysical Observatory, P.O. Box 3000, 90014 University of Oulu, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 6.5 MB)
Persistent link: http://urn.fi/urn:nbn:fi-fe2019100831968
Language: English
Published: Copernicus Publications, 2019
Publish Date: 2019-10-08
Description:

Abstract

Studying the uppermost structure of the subsurface is a necessary part of solving many practical problems (exploration of minerals, groundwater studies, geoengineering, etc.). The practical application of active seismic methods for these purposes is not always possible for different reasons, such as logistical difficulties, high cost of work, and a high level of seismic and acoustic noise. That is why developing and improving passive seismic methods is one of the important problems in applied geophysics. In our study, we describe a way of improving the quality of empirical Green’s functions (EGFs), evaluated from high-frequency ambient seismic noise, by using the advanced technique of cross-correlation function stacking in the time domain (in this paper we use term “high-frequency” for frequencies higher than 1 Hz). The technique is based on the global optimization algorithm, in which the optimized objective function is a signal-to-noise ratio of an EGF, retrieved at each iteration. In comparison to existing techniques, based, for example, on weight stacking of cross-correlation functions, our technique makes it possible to significantly increase the signal-to-noise ratio and, therefore, the quality of the EGFs. The technique has been tested with the field data acquired in an area with a high level of industrial noise (Pyhäsalmi Mine, Finland) and in an area with a low level of anthropogenic noise (Kuusamo Greenstone Belt, Finland). The results show that the proposed technique can be used for the extraction of EGFs from high-frequency seismic noise in practical problems of mapping of the shallow subsurface, both in areas with high and low levels of high-frequency seismic noise.

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Series: Solid earth
ISSN: 1869-9510
ISSN-E: 1869-9529
ISSN-L: 1869-9510
Volume: 10
Pages: 1621 - 1634
DOI: 10.5194/se-10-1621-2019
OADOI: https://oadoi.org/10.5194/se-10-1621-2019
Type of Publication: A1 Journal article – refereed
Field of Science: 1171 Geosciences
Subjects:
Funding: The study is a part of the SEISLAB project funded by the European Regional Development Fund (ERDF), the Council of Oulu region (Finland), and the Pyhäsalmi Mine Oy and of the ARCEMIS project funded by the KVANTUM Institute of the University of Oulu. The theoretical part of the study was funded by the Federal Agency of Scientific Organizations (project no. AAAA-A18-118012490072-7) and research mobility grant (no. 31166) by the Academy of Finland.
Copyright information: © Author(s) 2019. This work is distributed under the Creative Commons Attribution 4.0 License.
  https://creativecommons.org/licenses/by/4.0/