The Papuan Fold and Thrust Belt (PFTB) in Papua New Guinea is actively forming within a complex tectonic setting at the boundary of the obliquely converging Australian and Pacific plates. The tectonic setting and inaccessibility of the PFTB make it one of the least well‐understood fold and thrust belts on Earth. On February 25, 2018, a M_w 7.5 earthquake occurred within the PFTB, triggering an aftershock sequence which included five events ≥M_w 6. In this study, we combine seismological, GPS and remote sensing observations to investigate the spatiotemporal distribution of crustal deformation during these events. All earthquakes ≥M_w 6 were related to reverse offset on northeast‐dipping fault planes and five out of the six, including the mainshock, were associated with midcrustal focal depths (∼15–30 km). During the sequence, the PFTB underwent up to 1.2 m of uplift and ground deformation occurred over 7,500 km². Combining these observations with our geological knowledge of this convergent margin highlights the primary control of the northern Australian passive margin on PFTB structural style. We propose that the earthquake sequence was related to tectonic inversion on a hidden extensional fault system beneath the PFTB and lateral variations along this fault zone had significant influence on the complex distribution of ground deformation. It follows that this fault system has had an important control on the evolution of variable structural styles within the PFTB. This study highlights the complexity that can characterize the evolution and structural style of fold and thrust belts.

中文翻译：

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巴布亚新几内亚2018年Mw 7.5高地地震：主动褶皱和冲断带对结构样式的影响

巴布亚新几内亚的巴布亚褶皱冲断带（PFTB）在倾斜的澳大利亚和太平洋板块交界处的复杂构造环境中活跃地形成。PFTB的构造环境和难以进入的地理位置使其成为地球上最难理解的褶皱和逆冲带之一。在2018年2月25日，A M _{w ^} 7.5级地震的PFTB内发生，引发其中包括五个事件≥M余震序列_W¯¯ 6.在这项研究中，我们结合地震，全球定位系统和遥感观测来研究地壳变形的时空分布在这些事件中。所有地震≥M _{w ^}6个与东北倾断层平面的反向偏移有关，包括主震在内的6个中有5个与中地壳震源深度（约15-30 km）有关。在此序列中，PFTB经历了高达1.2 m的隆起，并且在7,500 km ^2的上方发生了地面变形。。将这些观察结果与我们对该收敛边缘的地质知识相结合，突出显示了北澳大利亚被动边缘对PFTB结构样式的主要控制。我们认为，地震序列与PFTB下方的隐性伸展断裂系统的构造反转有关，沿该断裂带的横向变化对地面变形的复杂分布有重要影响。因此，该断层系统对PFTB内可变结构样式的演变具有重要的控制作用。这项研究强调了可以表征褶皱和冲断带演化和结构样式的复杂性。