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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 2:09 |
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Conference: Bucharest University Faculty of Physics 2018 Meeting
Section: Atmosphere and Earth Science; Environment Protection
Title:
Correlations between geomagnetic anomalies recorded at Muntele Rosu Seismic Observatory (Romania) and the seismicity of Vrancea zone
Authors:
Andrei MIHAI(1), Iren-Adelina MOLDOVAN(1), Victorin TOADER(1), Raluca PARTHENIU(1), Laura PETRESCU(1)
Affiliation:
1) National Institute for Earth Physics, RO- 077825, Calugareni st, no 12, Magurele, Ilfov, Romania
E-mail
mihai.a.andrei@gmail.com
Keywords:
anomalies, Vrancea zone, geomagnetic measurements,intermediate earthquakes
Abstract:
In this paper, a relationship between Mw>4.5 earthquakes and geomagnetic anomalies recorded at one magnetometer located near Vrancea zone is examined. In order to highlight the anomalies recorded at Muntele Rosu (MLR) observatory, these data were compared with Surlari (SUA) observatory records located about 100Km South-East to Vrancea zone. To better distinguish the regional anomalies from global geomagnetic storms, both MLR and SUA datasets were also correlated with the geomagnetic indices taken from NOAA/Space Prediction Center. In this study were used recorded data from 2013 till present, and before being used, there were corrected missing and wrong data induced by malfunction of the data acquisition system. During these 5 years of investigations, 3 intermediate depth earthquakes with a moment magnitude Mw larger than 5.0 occurred in the Vrancea zone. All three events were accompanied by significant anomalies on the Y-axis (W-E component) of local geomagnetic field measured at MLR observatory. Similarly, earthquakes with Mw between 4.5 and 5 are accompanied by small anomalies, where a drop on Y-axis of few to 10nT was seen, instead of 20-30nT as the significant anomalies. The small anomalies are harder to see during the summertime when these anomalies are hidden by large diurnal variations. Another problem in detection these anomalies is the presence of geomagnetic storms which create false anomalies or hide the existence of these. To avoid the instrument errors regarding temperature, the geomagnetic measurements were compared with temperature values recorded on MLR station. The three major intermediate earthquakes produced in this interval provided a good opportunity to investigate the link between seismicity in Vrancea zone and the presence of anomalies recorded at MLR observatory.
Acknowledgement:
This paper was carried out within Nucleu Program, supported by ANCSI, project no. PN18150101/2018 and PN18150203/2018
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