山东台网大震速报定位策略--以山东济南M4.1地震为例

Locating Strategy of Earthquake Rapid Report of Shandong Seismic Network--Taking the Shandong Ji'nan M4.1 Earthquake as an Example

以2020年2月18日山东济南M4.1地震为例,使用山东区域台网记录的132个测震台站的震相数据,采用区域台网JOPENS-MSDP软件中Haposat、单纯型法和LocSAT等定位方法,分析了台站空隙角与定位台站震中距对定位结果中震中位置偏差的影响,及台站震中距对定位震级偏差的影响。结果表明:①区域台网在大震速报时应选择震中距较小且台站空隙角最小的台站组合,分析其震相到时数据来进行震中位置测定,如果遇到近场台站故障等特殊情况无法满足理想状态时,可适当添加较远台站以减小空隙角的方式来提高定位精度;②选取震中距大于170 km的台站地震波形振幅来测定地震震级结果比较可靠,震中距较近台站测算的震级值会偏小。

Taking the M4.1 earthquake in Ji'nan as an example,we conducted an amount of phases recorded by 132 stations in Shandong with Hapsat,Simple and LocSAT methods.Meanwhile,we not only analyzed the influence on precise location between gap angle and the nearest station,but also indicated the relationship between the magnitude and epicentral distance.The results show that the nearest station in the regional network should be used and the combination of seismic phase time data with the smallest gap angle should be selected to determine the location of the epicenter during the rapid report of a major earthquake.If the near-field station failure and other special circumstances cannot meet the ideal state,it is appropriate to add more distant stations to reduce the gap angle to improve the positioning accuracy.In order to determine the magnitude of an earthquake.It is necessary to use the amplitude data of stations larger than 170 km to calculate the result reliably.If the magnitude value calculated by the nearer station is used,it will be smaller.