Abstract Previous studies have found discrepancies concerning the seismic radiation between planar and curved faults; moment tensor (MT) interpretations, seismic moment estimation and waveforms change dramatically when the rupture is not planar. Therefore, assuming a point source on a planar fault for earthquakes in volcanic environments can be an oversimplification that needs to be addressed if we observe some seismological clues. We study MT inversions for the biggest earthquakes during the 2014–2015 collapse of the Barðarbunga caldera, which show non-double couple solutions, with vertical compression axis. We calculate synthetic seismograms for partial-ring ruptures using an ideal seismic network, and one emulating the existing monitoring network at Barðarbunga. Observations using distal stations can return a better-constrained seismic moment, but they fail to characterise the dynamics involved. On the other hand, using proximal stations we obtain a reliable representation of the forces involved; however, the seismic moment is systematically overestimated due to the proximity to the curved source and the corresponding focusing effects. Finally, we correct the area of rupture due to fault shape to estimate the real cumulative seismic moment during the caldera collapse. The result shows a closer relationship between seismic and geodetic moment.

中文翻译：

---

协调地震和大地测量力矩估计：Case Bárðarbunga

摘要 前人研究发现平面断层与弯曲断层地震辐射存在差异；当破裂不是平面时，矩张量 (MT) 解释、地震矩估计和波形会发生显着变化。因此，假设火山环境中地震的平面断层上的点源可能过于简单化，如果我们观察到一些地震学线索，就需要解决这个问题。我们研究了 2014 年至 2015 年 Barðarbunga 火山口坍塌期间最大地震的 MT 反演，其中显示了具有垂直压缩轴的非双偶解。我们使用理想的地震网络和模拟 Barðarbunga 现有监测网络计算部分环破裂的合成地震图。使用远端台站的观测可以返回更好的约束地震矩，但他们未能描述所涉及的动态。另一方面，使用近端站，我们可以获得所涉及力的可靠表示；然而，由于靠近弯曲源和相应的聚焦效应，地震矩被系统地高估了。最后，我们校正断层形状导致的破裂区域，以估计火山口坍塌期间的真实累积地震矩。结果表明地震和大地力矩之间的关系更密切。我们校正断层形状导致的破裂区域，以估计火山口坍塌期间的真实累积地震矩。结果表明地震和大地力矩之间的关系更密切。我们校正断层形状导致的破裂区域，以估计火山口坍塌期间的真实累积地震矩。结果表明地震和大地力矩之间的关系更密切。