References

NHESS

Natural Hazards and Earth System Sciences

NHESS

Nat. Hazards Earth Syst. Sci.

1684-9981

Copernicus Publications

Göttingen, Germany

10.5194/nhess-11-3171-2011

Analysis of the local lithospheric magnetic activity before and after Panzhihua Mw = 6.0 earthquake (30 August 2008, China)

Dudkin

¹ Korepanov

¹ Yang

² Li

² Leontyeva

Lviv Centre of Institute for Space Research, 5-A Naukova St., Lviv, 79060, Ukraine

Institute of Geophysics, 5, Minzudaxue Nanlu, Haidian Dist., Beijing, 100081, China

TeleConsult Austria GmbH, Graz, Austria

07 12 2011

11 12 3171 3180

2011

This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/

This article is available from https://nhess.copernicus.org/articles/11/3171/2011/nhess-11-3171-2011.html

The full text article is available as a PDF file from https://nhess.copernicus.org/articles/11/3171/2011/nhess-11-3171-2011.pdf

Lithospheric ultra low frequency (ULF) magnetic activity is recently considered as a very promising candidate for application to short-time earthquake forecasting. However the intensity of the ULF lithospheric magnetic field is very weak and often masked by much stronger ionospheric and magnetospheric signals. The study of pre-earthquake magnetic activity before the occurrence of a strong earthquake is a very hard problem which consists of the identification and localization of the weak signal sources in earthquake hazardous areas of the Earth's crust. For the separation and localization of such sources, we used a new polarization ellipse technique (Dudkin et al., 2010) to process data acquired from fluxgate magnetometers installed in the Sichuan province, China. Sichuan is the region of the strongest seismic activity on the territory of China. During the last century, about 40 earthquakes with magnitude M ≥ 6.5 happened here in close proximity to heavy populated zones. The Panzhihua earthquake Mw = 6.0 happened in the southern part of Sichuan province on 30 August 2008 at 8:30:52 UT. The earthquake hypocentre was located at 10 km depth. During the period 30–31 August – the beginning of September 2008, many clustered aftershocks with magnitudes of up to 5.6 occurred near the earthquake epicentre. The data from three fluxgate magnetometers (belonged to China magnetometer network and placed near to the clustered earthquakes at a distance of 10–55 km from main shock epicenter) have been processed. The separation between the magnetometers was in the range of 40–65 km. The analysis of a local lithospheric magnetic activity during the period of January–December 2008 and a possible source structure have been presented in this paper.

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