Strike-slip faults on Europa: Global shear patterns driven by tidal stress
Strike-slip faults on Europa: Global shear patterns driven by tidal stress
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欧罗巴上的走滑断层：潮汐应力驱动的全球剪切模式
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
P. Geissler
中科院分区：
文献类型：
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作者：
G. Hoppa;B. Tufts;R. Greenberg;P. Geissler
摘要由于轨道偏心率引起的周日潮汐可能会通过“行走”过程驱动木卫二的走滑运动，在这个过程中，断层以交替的左右侧向剪切异相打开和关闭。木卫二上五个不同区域的地图显示了121个走滑断层，包括Astypalaea Linguistic，一个800公里长的断层，右侧偏移42公里。在南半球高纬度地区，Astypalaea Linguistics附近的所有走滑断层都是右旋的。木卫二似乎倾向于在南半球形成右侧断层，在北方半球形成左侧断层，这与潮汐行走一致。在这五个位置上，非同步旋转解释了方位角方向和剪切方向的分布，它们适合于它们当前位置以西60°到90°的地层。或者，由于差异旋转的应力也可以解释所观察到的剪切模式。几乎所有确定的走滑断层都与双脊或带有关，但很少有沿着无脊裂缝（甚至更老的裂缝）。因此，没有脊的裂缝可能没有穿透到去耦层，这与脊形成的模型一致，该模型需要裂缝穿透到液态水海洋。
Abstract Diurnal tides due to orbital eccentricity may drive strike–slip motion on Europa through a process of “walking” in which faults open and close out of phase with alternate right- and left-lateral shear. Mapping of five different regions on Europa has revealed 121 strike–slip faults, including Astypalaea Linea, a 800-km-long fault with 42 km of right-lateral offset. At high southern latitudes near Astypalaea Linea all of the strike slip faults identified were right-lateral. Europa appears to preferentially form right-lateral faults in the southern hemisphere and left-lateral faults in the northern hemisphere, consistent with tidal walking. At the five locations, nonsynchronous rotation explains the azimuthal orientations and distribution of sense of shear, which fit formation ∼60° to 90° west of their current positions. Alternatively, stress due to differential rotation might also explain the observed shear patterns. Nearly all identified strike–slip faults were associated with double ridges or bands, but few were detected along ridgeless cracks (even older ones). Thus, cracks without ridges may not have penetrated to a decoupling layer, consistent with the models for ridge formation that require cracks to penetrate to a liquid water ocean.