| 钙钛矿蠕变对俯冲带震源深度极限的约束 |
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| 引用本文： | 许俊闪. 钙钛矿蠕变对俯冲带震源深度极限的约束[J]. 地球物理学报, 2014, 57(10): 3218-3225, doi: 10.6038/cjg20141010 |
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| 作者姓名： | 许俊闪 |
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| 作者单位： | 中国地震局地壳应力研究所, 地壳动力学重点实验室, 北京 100085 |
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| 基金项目： | 中央公益性科研院所基本业务专项基金(ZDJ2012-21)和国家自然科学基金(41304062)资助. |
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| 摘 要： | 本文利用林伍德石、钙钛矿两种矿物在不同差应力下随温度变化的蠕变曲线,通过约束温度条件和板块俯冲引起的弹性应变率,得到了俯冲带670 km深度可能的应力范围. 结果显示,在俯冲带670 km深度基于林伍德石蠕变得到应力大小可能超过100 MPa,而相变为钙钛矿后仅为0.1~10 MPa. 通过分析认为钙钛矿的Si扩散引起的快速应变率使得670 km更深深度的俯冲带无法支持较大的应力,可能是下地幔地震终止的原因,而不需要考虑亚稳态相变导致反裂隙断层的消失或林伍德石分解后超塑性等影响.
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| 关 键 词： | 钙钛矿 深源地震 位错蠕变 |
| 收稿时间： | 2013-05-06 |
| 修稿时间： | 2014-01-18 |
Perovskite rheological constraints on the depth limit of deep earthquakes in the subduction zone |
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| XU Jun-Shan. Perovskite rheological constraints on the depth limit of deep earthquakes in the subduction zone[J]. Chinese Journal of Geophysics (in Chinese), 2014, 57(10): 3218-3225, doi: 10.6038/cjg20141010 |
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| Authors: | XU Jun-Shan |
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| Affiliation: | Key Laboratory of Crustal Dynamics, Institute of Crustal Dynamics, China Earthquake Administration, Beijing 100085, China |
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| Abstract: | In this study, the stress levels at 670 km depth in the subduction zone were obtained. The creep curves of ringwoodite and perovskite were plotted at different stresses against temperatures. The stress values were obtained from those plots by constraining temperature range and the elastic strain rate caused by slab subduction. Our results showed that in the subduction zone the stress for ringwoodite creep may be over 100 MPa. However, for perovskite, the stress accumulation is only at a level of 0.1~10 MPa. We proposed that the high creep strain rate of perovskite caused by fast Si diffusion rate leads to the low stress accumulating limits at 670 km after the phase transformation from ringwoodite to perovskite. That can account for the depth limit of earthquakes in subdcution zone and there is no need of the transformational faulting caused by the olivine-spinel transformation or superplasticity of ringwoodite dissociation products. |
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| Keywords: | Perovskite Deep earthquake Dislocation creep |
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