地震研究

基于GREAT程序,利用GPS和BDS/GPS融合PPP(精密单点定位)获取了2021年玛多MW7.4地震10个高频GNSS测站的地震时间序列,并通过历元间差分法获得了震前30 min的速度时间序列。分析发现,相对于GPS,BDS/GPS速度时间序列在东西、北南、垂直3个方向的精度分别提高了14.8%、15.2%和3.5%。利用STA/LTA(短时窗平均/长时窗平均)方法,从各测站GPS和BDS/GPS时间序列中提取了地震波初至时刻; 利用2种时间序列计算得到的震中位置和发震时刻分别为(34.6°N,98.54°E),18:04:28.8和(34.63°N,98.51°E),18:04:29.2(UTC); 利用GPS和BDS/GPS峰值地面位移,根据经验公式反演了玛多地震震级分别为MW7.34和MW7.36,BDS/GPS震级与GCMT公布的结果(MW7.4)更为接近。结果表明:BDS/GPS融合PPP解算可提高时间序列稳定性并降低噪声,更真实地描述震时地表位移变化,从而提高震级解算准确性,更好地为地震预警、地震应急救援等工作提供数据支持。

The seismic time series of 10 high-rate GNSS stations during the 2021 Maduo MW7.4 earthquake were acquired using GPS and BDS/GPS fusion PPP based on the GREAT program,and the velocity time series 30 minutes before the earthquake were obtained based on the variometric approach.The analysis found that the BDS/GPS relative to GPS velocity RMS values in the EW,NS and UP orientation can be improved by 14.8%,15.2% and 3.5% respectively.The seismic wave's first arrival-time was extracted from the BDS/GPS time series of each station using the STA/LTA method,the location of the epicenter of the Maduo earthquake was(34.63°N,98.51°E),and the earthquake's original time was 18:04:29(UTC),calculated from the time of first arrival of seismic waves at each station.This article refers to the time of the Maduo earthquake,using the Coordinated Universal Time.The epicenter of the Maduo earthquake calculated by GPS time series is(34.6°N,98.54°E),and the original time is 18:04:28.8.Using GPS and BDS/GPS peak ground displacement,the Maduo earthquake magnitude was inverted according to the empirical formula,and the obtained magnitudes were MW7.36 and MW7.34,respectively.The BDS/GPS magnitude was closer to the result published by GCMT.The results show that the BDS/GPS fusion PPP solution can improve the stability of time series and reduce noise,which can more realistically describe the surface displacement changes during the earthquake,thus improving the accuracy of the magnitude solution and providing better data support for earthquake early warning and post-earthquake rescue.

引言
1 BDS/GPS融合PPP解算方法
2 BDS/GPS融合PPP获取玛多地震动态形变
3 用BDS/GPS测定玛多地震三要素
4 结论

图1 2021年玛多MW7.4地震震中附近区域测站位置分布<br/>Fig.1 The distribution of GNSS stations in the 2021 Maduo MW7.4 earthquake region

图1 2021年玛多MW7.4地震震中附近区域测站位置分布
Fig.1 The distribution of GNSS stations in the 2021 Maduo MW7.4 earthquake region

图2 2021年玛多MW7.4地震高频BDS时间序列<br/>Fig.2 The coordinate time series from high-rate BDS data of the 2021 Maduo MW7.4 earthquake

图2 2021年玛多MW7.4地震高频BDS时间序列
Fig.2 The coordinate time series from high-rate BDS data of the 2021 Maduo MW7.4 earthquake

图3 2021年玛多MW7.4地震高频GPS时间序列<br/>Fig.3 The coordinate time series from high-rate GPS data of the 2021 Maduo MW7.4 earthquake

图3 2021年玛多MW7.4地震高频GPS时间序列
Fig.3 The coordinate time series from high-rate GPS data of the 2021 Maduo MW7.4 earthquake

图4 2021年玛多MW7.4地震高频BDS/GPS时间序列<br/>Fig.4 The coordinate time series from high-rate BDS/GPS data of the 2021 Maduo MW7.4 earthquake

图4 2021年玛多MW7.4地震高频BDS/GPS时间序列
Fig.4 The coordinate time series from high-rate BDS/GPS data of the 2021 Maduo MW7.4 earthquake

表1 玛多地震前30 min各测站的速度时间序列RMS值<br/>Tab.1 RMS values of velocity time series of each station 30 minutes before the Maduo earthquake

表1 玛多地震前30 min各测站的速度时间序列RMS值
Tab.1 RMS values of velocity time series of each station 30 minutes before the Maduo earthquake

图5 LAJA测站GPS和BDS/GPS可视卫星数及GDOP值<br/>Fig.5 Number of Satellites of GPS and BDS/GPS and GDOP values for LAJA

图5 LAJA测站GPS和BDS/GPS可视卫星数及GDOP值
Fig.5 Number of Satellites of GPS and BDS/GPS and GDOP values for LAJA

表2 部分测站地震波初至时刻<br/>Tab.2 First arrival-time of seismic waves at some stations

表2 部分测站地震波初至时刻
Tab.2 First arrival-time of seismic waves at some stations

图6 本文计算震中位置与不同机构发布震中分布<br/>Fig.6 Calculated epicenters and the epicenter published by the China Seismic Networks Center

图6 本文计算震中位置与不同机构发布震中分布
Fig.6 Calculated epicenters and the epicenter published by the China Seismic Networks Center

表3 本文与其它机构所得震中及发震时刻结果对比<br/>Tab.3 The epicenter and the original time of the Maduo earthquake from the other agencies and from the author

表3 本文与其它机构所得震中及发震时刻结果对比
Tab.3 The epicenter and the original time of the Maduo earthquake from the other agencies and from the author

图7 KANQ测站震时水平方向坐标及H值变化<br/>Fig.7 Changes of horizontal coordinates and H value at KANQ station during the Maduo earthquake

图7 KANQ测站震时水平方向坐标及H值变化
Fig.7 Changes of horizontal coordinates and H value at KANQ station during the Maduo earthquake

表4 使用所有测站的PGD估算的震级<br/>Tab.4 PGD magnitudes for all stations

表4 使用所有测站的PGD估算的震级
Tab.4 PGD magnitudes for all stations

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备注

引言

1 BDS/GPS融合PPP解算方法

2 BDS/GPS融合PPP获取玛多地震动态形变

3 用BDS/GPS测定玛多地震三要素

4 结论

期刊信息