Low-degree toroidal modes from the Sumatra-Andaman event observed by superconducting gravimeters

作者：Chuang Xu,Hangtao Yu,Guangyu Jian,Shiqi Deng,Boyang Zhou,Yihao Wu

摘要：The complex frequencies of the low-degree toroidal modes are helpful in constraining the mantle structure.In the early years,the traditional method to detect the low-degree toroidal modes is seismic approach,which is primarily limited by the horizontal noise of seismometers.Recently,it has been proved that gravity method is competitive.Therefore,we re-estimated or newly estimated the complex frequencies of the toroidal modes below 1.5 mHz excited by the 2004 Sumatra-Andaman event using gravity method in this paper.The results show that(1)The quality factors of0 T5-0 T9 and1 T2-1 T3 are estimated from superconducting gravity data for the first time;(2)The estimated frequencies and quality factors for0 T2-0 T9 and1 T2-1 T3 are consistent with those provided by previous publications,which verifies the correctness and effectiveness of our estimations;(3)The maximum difference of frequencies between our results and those from CPREM is on the order of 0.01 mHz and the maximum difference of quality factors is at the level of 10.

发文机构：Department of Surveying Engineering State Key Laboratory of Geodesy and Earth’s Dynamics State Key Laboratory of Information Engineering in Surveying School of Earth Science and Engineering

关键词：Low-degreeTOROIDALMODESSUPERCONDUCTINGgravitydataComplexfrequencyQualityfactor

分类号： P315.62[天文地球—地震学][天文地球—固体地球物理学][天文地球—地球物理学]