• 责任者：Zhou Yiyan (Institute of Seismology ; China Earthquake Administration ; Wuhan 430071 ; China) ; Wu Yun
• 刊名：Chinese Journal of Geophysics
• 出版年：2010
• 卷期：53(3)
• 关键词：汶川地震2008 ; Wenchuan earthquake 2008 ; 电离层 ; ionosphere ; 地震前兆 ; precursor ; 四川 ; Sichuan Province
• 页码：p.556-566
• 图表：9 illus., 76 refs.
• 分类号：0500
• issnNo：ISSN0001-5733
• isbnNo：CN11-2074/P

MsoNormal style="MARGIN: 0cm 0cm 0pt">In this paper, we investigated the variations of the ionospheric Vertical Total Electron Content (VTEC) derived from the ground-based GPS observations during the 12 May 2008 M_s8.0 Wenchuan earthquake. A mean of the previous 10-day VTECs and the associated two standard deviations are utilized as a reference for identifying the ionospheric anomalies. The analysis showed that (1) the anomalous enhancements of VTEC appeared on May 3 and 9, while the anomalous decreases appeared on April 29 and May 6; (2)all of the ionospheric anomalies lasted beyond 4 hours and drifted from east to west; (3)relative to a non-perturbed state of the ionosphere, the zones of the VTEC decrease or enhancement by more than 30% around the epicenter had spatial scale of more than ml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />metcnv w:st="on" UnitName="km" SourceValue="4000" HasSpace="True" Negative="False" NumberType="1" TCSC="0">4000 kmmetcnv> in longitude and metcnv w:st="on" UnitName="km" SourceValue="1500" HasSpace="True" Negative="False" NumberType="1" TCSC="0">1500 kmmetcnv> in latitude at five peak times of the ionospheric anomalies. In view of the solar-terrestrial environment and the characters of the ionospheric anomalies, we think that the positive anomalies of VTEC in the afternoon of May 3 and on May 9 are probably the ionospheric precursors of Wenchuan earthquake.ml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />