Monitoring earthquakes to rapidly forecast their consequences remains a challenging task, especially in areas far from seismic and geodetic networks. Large and shallow earthquakes induce disturbances in the ionospheric Total Electron Content (TEC). These disturbances are commonly detected using Global Navigation Satellite Systems (GNSS) stations that can sound the ionosphere at great distances. To address this instrumentation sparsity issue, we assess a single GNSS station's ability to constrain the origin location of a coseismic ionospheric disturbance (CID) using observations of TEC. We develop a grid-search method that explores different trial origins (i.e. source locations) to determine which synthetic CID signal best matches the observed TEC time series.

We confirm that a larger number of monitoring satellites enhances the opportunity to have the favorable geometrical coverage of satellites needed to resolve CID origins. We use TEC data acquired during two earthquakes having different moment magnitudes: a Mw 7.1 from Turkey and a Mw 7.8 from New Zealand. Using a well-placed multi-GNSS station we are able to retrieve the CID origin with an accuracy of 50 km and a theoretical precision of the same order. We conclude that a very sparse network of multi-GNSS stations can provide an independent estimate of the spatial distribution of large scale coseismic motions, including offshore areas 200–300 km from the coastline.

监测地震以快速预测其后果仍然是一项具有挑战性的任务，尤其是在远离地震和大地测量网络的地区。大地震和浅地震会引起电离层总电子含量 (TEC) 的扰动。这些干扰通常是使用全球导航卫星系统 (GNSS) 站检测到的，这些站可以远距离探测电离层。为了解决这个仪器稀疏问题，我们使用 TEC 的观测来评估单个 GNSS 站限制同震电离层扰动 (CID) 起源位置的能力。我们开发了一种网格搜索方法，该方法探索不同的试验来源（即源位置）以确定哪个合成 CID 信号与观察到的 TEC 时间序列最匹配。

我们确认，更多的监测卫星增加了获得解决 CID 起源所需卫星的有利几何覆盖范围的机会。我们使用在具有不同矩震级的两次地震中获得的 TEC 数据：来自土耳其的 Mw 7.1 和来自新西兰的 Mw 7.8。使用位置良好的多 GNSS 站，我们能够以 50 公里的精度和相同数量级的理论精度检索 CID 原点。我们得出的结论是，一个非常稀疏的多 GNSS 站网络可以提供对大规模同震运动空间分布的独立估计，包括距海岸线 200-300 公里的近海区域。