The Quito Basin, a narrow NE‐trending tectonic depression, contains a perched Quaternary volcaniclastic sequence juxtaposed against the Interandean Depression through the Quito fault system (QFS). Syntectonic infilling, which occurs during a piggy‐back phase, consists of alluvial fan sets grading eastward into lacustrine facies. The western piedmont margin overlies the foothills of Quaternary volcanoes. Classic thrust tectonic models predict basinward propagation of low‐angle thrusts ahead of master faults. A magnetotelluric survey was used to investigate the western Quito piedmont. Three resistivity sections show similar geoelectrical assemblages. From west to east, a wedge‐shaped high‐resistivity structural high abuts a low‐resistivity domain, representing a fold‐thrust belt overriding a foreland basin. This set continues to the east with a new high‐resistivity structural high sliced by low‐angle imbricated thrusts that culminate in local thrust‐top troughs before grading into a deeper low‐resistivity trough against the younger QFS anticlines. Thus, the Quito master thrust system results in a prominent basin‐facing monocline affecting the foothills of Quaternary volcanoes.

中文翻译：

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通过大地电磁探测厄瓜多尔基多西部安第斯山麓的主推力系统

基多盆地是一个狭窄的北东向构造凹陷，包含一个通过基多断层系统（QFS）与南极洲凹陷并列的栖息的第四纪火山碎屑序列。在背a阶段发生的同构造充填由冲积扇组组成，向东逐渐划分为湖相。西山前缘覆盖第四纪火山的山麓。经典的逆冲构造模型预测在主断层之前低角度逆冲向盆地的传播。大地电磁调查用于调查西基多山麓。三个电阻率部分显示相似的地电组合。从西向东，一个楔形高电阻率构造高地毗邻一个低电阻率区域，代表了一个覆盖前陆盆地的褶皱冲断带。该区域继续向东延伸，新的高电阻率构造高地被低角度的胶结冲断层切开，最终在局部冲断顶槽处达到顶峰，然后逐渐向着较年轻的QFS背斜过渡到更深的低电阻率槽内。因此，基多主推力系统导致了一个显着的面向盆地的单斜线，影响了第四纪火山的山麓。