美国得克萨斯大学
课题组研究发现，在Hikurangi北部边缘，大型逆冲断层携带的物质的摩擦愈合率几乎为零(每十年小于0.0001)，该区域具有典型的周期性浅层慢滑事件(SSEs)。这些低愈合率为Hikurangi和其他俯冲边缘浅层慢滑事件的低应力降(<50千帕)和短复发时间(1至2年)提供了一种机制。研究人员认为，接近于零的摩擦愈合速率，与俯冲带中常见的薄层硅酸盐有关，可能会促进海沟附近频繁的、小应力降的、缓慢的破裂。
据悉，浅俯冲巨型逆冲断层上的板块运动受一系列构造滑动模式的调节。然而，维持这些不同的滑行行为的摩擦特性和条件仍然是个谜。摩擦愈合就是这样一种性质，它描述了两次地震之间断层再强化的程度。
附：英文原文
Title: Ultralow frictional healing explains recurring slow slip events
Author: Srisharan Shreedharan, Demian Saffer, Laura M. Wallace, Charles Williams
Issue&Volume: 2023-02-17
Abstract: Plate motion on shallow subduction megathrusts is accommodated by a spectrum of tectonic slip modes. However, the frictional properties and conditions that sustain these diverse slip behaviors remain enigmatic. Frictional healing is one such property, which describes the degree of fault restrengthening between earthquakes. We show that the frictional healing rate of materials entrained along the megathrust at the northern Hikurangi margin, which hosts well-characterized recurring shallow slow slip events (SSEs), is nearly zero (<0.0001 per decade). These low healing rates provide a mechanism for the low stress drops (<50 kilopascals) and short recurrence times (1 to 2 years) characteristic of shallow SSEs at Hikurangi and other subduction margins. We suggest that near-zero frictional healing rates, associated with weak phyllosilicates that are common in subduction zones, may promote frequent, small-stress-drop, slow ruptures near the trench.
DOI: adf4930
Source: https://www.science.org/doi/10.1126/science.adf4930