Retrieving real-time co-seismic displacements using GPS/GLONASS: a preliminary report from the September 2015 Mw 8.3 Illapel earthquake in Chile
Retrieving real-time co-seismic displacements using GPS/GLONASS: a preliminary report from the September 2015 Mw 8.3 Illapel earthquake in Chile
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DOI：
10.1093/gji/ggw190
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发表时间：
2016-08-01
影响因子：
2.8
通讯作者：
Tu, Rui
中科院分区：
文献类型：
--
作者：
Chen, Kejie;Ge, Maorong;Tu, Rui
与单一GPS系统相比，GPS/GLONASS观测可以提高卫星能见度，优化空间几何结构，提高精确定位性能。虽然GPS/GLONASS在定位方面的优势很明显，但GPS/GLONASS对同震位移确定和随后的震源反演的潜在贡献仍需要广泛的研究和验证。本文首先将时间点定位模型从GPS-only扩展到GPS/GLONASS观测。利用该模型，通过在振动台上进行的8次室外实验验证了GPS/GLONASS方法获取同震位移的性能。结果表明，在非最优观测环境下，GPS/GLONASS方法提供的同震位移比仅GPS观测更准确、更稳健。此外，作为一个案例研究，对2015年9月智利伊拉佩尔8.3级地震的观测数据进行了重新处理。在一些台站，仅用GPS和GPS/GLONASS观测得到的同震位移之间存在明显的偏差。随后在弯曲断层上的滑动分布反演证实了同震位移的差异导致反演结果的差异，并证实了GPS/GLONASS观测推断的Illapel地震的滑动分布倾向于更浅和更大。
Compared with a single GPS system, GPS/GLONASS observations can improve the satellite visibility, optimize the spatial geometry and improve the precise positioning performance. Although the advantage over GPS-only methods in terms of positioning is clear, the potential contributions of GPS/GLONASS to co-seismic displacement determination and the subsequent seismic source inversion still require extensive study and validation. In this paper, we first extended a temporal point positioning model from GPS-only to GPS/GLONASS observations. Using this new model, the performance of the GPS/GLONASS method for obtaining co-seismic displacements was then validated via eight outdoor experiments on a shaking table. Our result reveals that the GPS/GLONASS method provides more accurate and robust co-seismic displacements than the GPS-only observations in a non-optimal observation environment. Furthermore, as a case study, observation data recorded during the September 2015 M-w 8.3 Illapel earthquake in Chile were re-processed. At some stations, obvious biases were found between the co-seismic displacements derived from GPS-only and GPS/GLONASS observations. The subsequent slip distribution inversion on a curved fault confirms that the differences in the co-seismic displacements causes differences in the inversion results and that the slip distributions of the Illapel earthquake inferred from the GPS/GLONASS observations tend to be shallower and larger.