Faults of the Roer Valley Rift System (RVRS) are characterized by seismicity, scarps and displaced fluvial terraces, showing that they are active. The Heerlerheide fault is part of the southern boundary fault system of the RVRS, the Feldbiss fault zone (FFZ). During the late 19th and first half of the 20th century coal was mined in the subsurface south of the FFZ. As a result, general subsidence, sinkholes, and fault scarplets appeared on the surface. One of the induced fault scarps coincides with the location of the Heerlerheide fault, indicating that the upper part of the fault was reactivated by the mining. A trench was opened across the fault to study the mining-induced fault reactivation as well as the tectonic fault displacement history.

The Heerlerheide fault offsets a 340 ka Meuse river terrace overlain by loess and loess-like deposits of Eemian to Late Pleniglacial age, including the Rocourt soil, the Eben/Patina discordance and the Nagelbeek soil complex. At least three tectonic faulting events were reconstructed, which are most likely surface rupturing earthquakes. However, the two oldest displacements could represent multiple faulting events. The age of the youngest event is well constrained between 17 and 15 ka. The duration of the time interval between the penultimate and youngest events is at least 8 ky (the inter-event time is an important parameter for assessing seismic hazard). The vertical coseismic displacement of the youngest event was around ∼0.25 m; the estimated moment magnitude is around 6.2. This event is more or less synchronous with the age of events found in other fault trench studies of the FFZ. The timing is roughly contemporaneous with surface rupturing earthquakes along the northern boundary fault zone of the RVRS, the Peel Boundary fault zone (PBFZ), and a phase of volcanism in the nearby Eifel area, suggesting a common mechanism. The timing also corresponds to the start of the glacio-isostatic forebulge collapse, which has been invoked before to explain earthquake events in the RVRS, and in northern Germany and Denmark.

Previous studies provided evidence for a Holocene surface rupturing earthquake with an offset of about 1 m at the Geleen fault in the Meuse valley on Belgian territory, taking place between 2.5 ± 0.3 and 3.1 ± 0.3 ka. The Geleen and Feldbiss faults on Dutch territory experienced faulting during the Late Glacial – Holocene. The incision and deposition history of a brook crossing these faults suggests an age around 7.5 ka for this event. However, in contrast, our results for the Heerlerheide fault show no evidence for Late Glacial – Holocene tectonic fault activity.

We also observed 0.34 m of vertical displacement of the base of the plough layer, which corresponds to the amount to what was observed at the surface during the mining in 1936, indicating that no fault motions have occurred afterwards, despite re-flooding of the mines and consequent surface rebound. However, the fact that the fault was reactivated by subsurface mining shows that it is a weakness zone in the subsurface, and therefore fault reactivation might occur due to still ongoing rebound. In contrast to the tectonic fault displacement, the mining-induced offset was accompanied by downslope movement of the upper part of the hanging wall, resulting in splaying of the fault tip and crack formation.

Roer Valley Rift System (RVRS) 断层的特征是地震活动、陡坡和移位的河流阶地，表明它们是活跃的。Heerlerheide 断层是 RVRS 南部边界断层系统 Feldbiss 断层带 (FFZ) 的一部分。在 19 世纪末和 20 世纪上半叶，在 FFZ 以南的地下开采了煤炭。结果，地表出现普遍下沉、天坑和断层线。诱发断层陡坡之一与 Heerlerheide 断层的位置重合，表明断层上部因开采而重新活动。在断层上开辟了一条沟渠，以研究采矿引起的断层再激活以及构造断层位移历史。

Heerlerheide 断层抵消了一个 340 ka 的默兹河阶地，该阶地被 Eemian 至晚白冰期的黄土和类黄土沉积物覆盖，包括 Rocourt 土壤、Eben/Patina 不协调和 Nagelbeek 土壤复合体。至少重建了三个构造断层事件，它们很可能是地表破裂地震。然而，两个最古老的位移可能代表多个断层事件。最年轻的事件的年龄被很好地限制在 17 到 15 ka 之间。倒数第二次和最年轻的事件之间的时间间隔持续时间至少为 8 ky（事件间时间是评估地震危险性的重要参数）。最年轻事件的垂直同震位移约为 0.25 m；估计的矩震级约为 6.2。该事件或多或少与 FFZ 其他断层沟研究中发现的事件年龄同步。该时间与沿 RVRS 北部边界断层带、皮尔边界断层带 (PBFZ) 和附近埃菲尔地区的火山活动阶段的地表破裂地震大致同时发生，这表明了一个共同的机制。该时间也对应于冰川等静压前隆起坍塌的开始，之前曾用它来解释 RVRS 以及德国北部和丹麦的地震事件。

先前的研究提供了在比利时领土默兹河谷的 Geleen 断层处发生了大约 1 m 偏移量的全新世地表破裂地震的证据，发生在 2.5 ± 0.3 和 3.1 ± 0.3 ka 之间。荷兰领土上的 Geleen 和 Feldbiss 断层在晚冰期 - 全新世期间经历了断层。一条穿过这些断层的小溪的切口和沉积历史表明该事件的年龄约为 7.5 ka。然而，相比之下，我们对 Heerlerheide 断层的结果没有显示晚冰期 - 全新世构造断层活动的证据。

我们还观察到犁层底部 0.34 m 的垂直位移，这与 1936 年采矿期间在地表观察到的量相对应，表明尽管矿井重新注水，但之后没有发生断层运动以及随之而来的表面反弹。然而，断层被地下开采重新激活的事实表明它是地下的薄弱带，因此由于仍在继续反弹，可能会发生断层重新激活。与构造断层位移相反，采矿引起的偏移伴随着上壁上部的下坡运动，导致断层尖端张开并形成裂缝。