地壳脆塑性转化带非稳态流变与震后松弛变形机制

doi:10.13745/j.esf.sf.2020.9.41

摘要/Abstract

摘要：

大陆浅源地震密集分布层称为地震层,该深度处于石英脆塑性转化带,其变形除受温度控制外,地震周期各阶段变形随应变速率和应力发生变化,从间震期的稳态蠕变转化为同震破裂和震后松弛阶段非稳态蠕变。与间震期长期蠕变相关的野外塑性变形和稳态流变实验研究非常多,而与震后松弛相关的地壳深部脆塑性转化和非稳态蠕变研究非常有限,更缺少非稳态流变的本构方程。震后松弛阶段的断层滑动研究和基于GPS观测数据反演地壳形变研究都依赖于非稳态蠕变实验数据及其流变模型。本文介绍了野外断层脆塑性转化带非稳态流变和高温高压非稳态流变实验研究进展,分析震后松弛阶段断层脆塑性转化带的变形特征与变形模式,讨论了非稳态流变与脆塑性转化带强度定量化研究中存在的问题。

关键词: 非稳态流变, 震后松弛, 脆塑性转化带

Abstract:

The layer of major seismic events in continental crust at the depth of the quartz brittle-plastic transition zone is called seismogenic zone. The crustal deformation of this zone, controlled by temperature and affected by strain rate and stress, plays an important role during seismic cycle. The major deformation mechanism is steady state creep during interseismic deformation, then changing to rupture at coseismic loading and transient creep at postseismic relaxation. However, most of the studies in the past were focused on intersceismic creep-related ductile deformation in natural fault and steady state creep tests under high temperature. There have been very limited studies on transient creep-related postseismic relaxation based on geological survey of brittle-plastic fault transition and experiments under high temperature and pressure. Especially, there is an absence of constitutive equations related to transient creep at postseismic relaxation. Fault slip research and GPS observation-based simulation of crustal deformation during postseismic depend on the transient creep test data and rheological model. In this study, we report our research progress on transient creep in brittle-ductile fault zone and under high temperature/pressure, analyze the deformation mechanism and models and discuss issues in quantitative calculation of fault strength for transient creep in brittle-ductile transition zone.

Key words: transient creep, postseismic relaxation, brittle-plastic transition

中图分类号:

周永胜, 戴文浩. 地壳脆塑性转化带非稳态流变与震后松弛变形机制[J]. 地学前缘, 2022, 29(1): 403-412.

ZHOU Yongsheng, DAI Wenhao. Transient creep during crustal brittle-plastic transition and deformation mechanism of postseismic relaxation[J]. Earth Science Frontiers, 2022, 29(1): 403-412.

图/表 7

图1 同震加载、震后松弛、间震期蠕变阶段地震层与塑性层的应力状态、脆塑性转化深度、变形机制变化 (据文献[16,17]修改)

Fig.1 Changes of stress state,depth of brittle-plastic transition and deformation mechanism of seismogenic and plastic zones during coseismic loading, postseismic relaxation and interseismic creeping. Modified after [16-17].

图2 震后松弛过程的非稳态流变与裂隙愈合(据文献[6])

Fig.2 Transient creep and crack healing during postseismic relaxation. Adapted from [6].

图3 稳态流变与非稳态流变的应力-应变曲线

Fig.3 Stress-strain curves of steady state and transient creep

图4 花岗岩非稳态强度随深度的变化(据文献[50])

Fig.4 Variation of transient creep strain in granite with crustal depth. Adapted from [50].

图5 脆性破裂与动态变形组合模拟实验(据文献[6])

Fig.5 Combined simulation experiments on brittle fracture and dynamic deformation. Adapted from [6].

图6 裂隙愈合对岩石强度恢复影响实验(根据文献[38])

Fig.6 Effect of fracture healing on rock strength recovery. Adapted from [38].

图7 具有不同断层结构的英云闪长岩(a)与糜棱岩(b)岩石中裂隙愈合程度对岩石强度影响的对比实验(据文献[56])

Fig.7 Comparison of the effect of fracture healing on rock strength recovery in rocks with different deformation structures (Adapted from [56]). (a) Tonalite; (b) Mylonite.

参考文献 57

[1]	SCHOLZ C H. The mechanics of earthquakes and faulting[M]. Cambridge: Cambridge University Press, 2002.
[2]	HIRTH G, TULLIS J. The brittle-plastic transition in experimentally deformed quartz aggregates[J]. Journal of Geophysical Research: Solid Earth, 1994, 99(B6):11731-11747.
[3]	HIRTH G, TEYSSIER C, DUNLAP J W. An evaluation of quartzite flow laws based on comparisons between experimentally and naturally deformed rocks[J]. International Journal of Earth Sciences, 2001, 90(1):77-87. DOI URL
[4]	STÖCKHERT B, BRIX M R, KLEINSCHRODT R, et al. Thermochronometry and microstructures of quartz: a comparison with experimental flow laws and predictions on the temperature of the brittle-plastic transition[J]. Journal of Structural Geology, 1999, 21(3):351-369. DOI URL
[5]	TREPMANN C A, STÖCKHERT B, DORNER D, et al. Simulating coseismic deformation of quartz in the middle crust and fabric evolution during postseismic stress relaxation: an experimental study[J]. Tectonophysics, 2007, 442(1/2/3/4):83-104. DOI URL
[6]	TREPMANN C A, HSU C, HENTSCHEL F, et al. Recrystallization of quartz after low-temperature plasticity: the record of stress relaxation below the seismogenic zone[J]. Journal of Structural Geology, 2017, 95:77-92. DOI URL
[7]	KOCH N, MASCH L. Formation of Alpine mylonites and pseudotachylytes at the base of the Silvretta nappe, Eastern Alps[J]. Tectonophysics, 1992, 204(3/4):289-306. DOI URL
[8]	HE C R, YAO W M, WANG Z L, et al. Strength and stability of frictional sliding of gabbro gouge at elevated temperatures[J]. Tectonophysics, 2006, 427(1/2/3/4):217-229. DOI URL
[9]	HE C R, WANG Z L, YAO W M. Frictional sliding of gabbro gouge under hydrothermal conditions[J]. Tectonophysics, 2007, 445(3/4):353-362. DOI URL
[10]	周永胜, 韩亮, 靖晨, 等. 龙门山断层脆-塑性转化带流变结构与汶川地震孕震机制[J]. 地震地质, 2014, 36(3):882-895.
[11]	TSE S T, RICE J R. Crustal earthquake instability in relation to the depth variation of frictional slip properties[J]. Journal of Geophysical Research: Solid Earth, 1986, 91(B9):9452-9472.
[12]	BEN-ZION Y, RICE J R. Dynamic simulations of slip on a smooth fault in an elastic solid[J]. Journal of Geophysical Research: Solid Earth, 1997, 102(B8):17771-17784.
[13]	BEN-ZION Y, LYAKHOVSKY V. Analysis of aftershocks in a lithospheric model with seismogenic zone governed by damage rheology[J]. Geophysical Journal International, 2006, 165(1):197-210. DOI URL
[14]	ELLIS S, STÖCKHERT B. Elevated stresses and creep rates beneath the brittle-ductile transition caused by seismic faulting in the upper crust[J]. Journal of Geophysical Research: Solid Earth, 2004, 109(B5):B05407.
[15]	NÜCHTER J A, ELLIS S. Complex states of stress during the normal faulting seismic cycle: role of midcrustal postseismic creep[J]. Journal of Geophysical Research: Solid Earth, 2010, 115(B12):B12411.
[16]	TREPMANN C A, STÖCKHERT B. Short-wavelength undulatory extinction in quartz recording coseismic deformation in the middle crust: an experimental study[J]. Solid Earth, 2013, 4(2):263-276. DOI URL
[17]	TREPMANN C A, STÖCKHERT B. Quartz microstructures developed during non-steady state plastic flow at rapidly decaying stress and strain rate[J]. Journal of Structural Geology, 2003, 25(12):2035-2051. DOI URL
[18]	SCHAFF D P, BOKELMANN G H R, BEROZA G C, et al. High-resolution image of Calaveras Fault seismicity[J]. Journal of Geophysical Research: Solid Earth, 2002, 107(B9): ESE5-1.
[19]	DUNLAP W J, HIRTH G, TEYSSIER C. Thermomechanical evolution of a ductile duplex[J]. Tectonics, 1997, 16(6):983-1000. DOI URL
[20]	VAN DAALEN M, HEILBRONNER R, KUNZE K. Orientation analysis of localized shear deformation in quartz fibres at the brittle-ductile transition[J]. Tectonophysics, 1999, 303(1/2/3/4):83-107. DOI URL
[21]	STIPP M, STÜNITZ H, HEILBRONNER R, et al. The eastern Tonale fault zone: a ‘natural laboratory’ for crystal plastic deformation of quartz over a temperature range from 250 to 700 ℃[J]. Journal of Structural Geology, 2002, 24(12):1861-1884. DOI URL
[22]	NEVITT J M, WARREN J M, POLLARD D D. Testing constitutive equations for brittle-ductile deformation associated with faulting in granitic rock[J]. Journal of Geophysical Research: Solid Earth, 2017, 122(8):6269-6293. DOI URL
[23]	TREPMANN C, STÖCKHERT B. Mechanical twinning of jadeite: an indication of synseismic loading beneath the brittle-plastic transition[J]. International Journal of Earth Sciences, 2001, 90(1):4-13. DOI URL
[24]	TREPMANN C A, STÖCKHERT B. Cataclastic deformation of garnet: a record of synseismic loading and postseismic creep[J]. Journal of Structural Geology, 2002, 24(11):1845-1856. DOI URL
[25]	TREPMANN C A, STÖCKHERT B. Microfabric of folded quartz veins in metagreywackes: dislocation creep and subgrain rotation at high stress[J]. Journal of Metamorphic Geology, 2009, 27(8):555-570. DOI URL
[26]	KÜSTER M, STÖCKHERT B. High differential stress and sublithostatic pore fluid pressure in the ductile regime: microstructural evidence for short-term post-seismic creep in the Sesia Zone, Western Alps[J]. Tectonophysics, 1999, 303(1/2/3/4):263-277. DOI URL
[27]	TREPMANN C, LENZE A, STÖCKHERT B. Static recrystallization of vein quartz pebbles in a high-pressure-low-temperature metamorphic conglomerate[J]. Journal of Structural Geology, 2010, 32(2):202-215. DOI URL
[28]	ZHOU Y S, HE C R, YANG X S. Water contents and deformation mechanism in ductile shear zone of middle crust along the Red River fault in southwestern China[J]. Science in China Series D: Earth Sciences, 2008, 51(10):1411-1425.
[29]	WINTSCH R P, YI K. Dissolution and replacement creep: a significant deformation mechanism in mid-crustal rocks[J]. Journal of Structural Geology, 2002, 24(6/7):1179-1193. DOI URL
[30]	CAO S Y, NEUBAUER F, LIU J L, et al. Rheological weakening of high-grade mylonites during low-temperature retrogression: the exhumed continental Ailao Shan-Red River fault zone, SE Asia[J]. Journal of Asian Earth Sciences, 2017, 139:40-60. DOI URL
[31]	戴文浩, 周永胜. 震后松弛阶段脆-塑性转化带的变形: 以红河断裂为例[J]. 地震地质, 2019, 41(4):996-1011.
[32]	HAN L, ZHOU Y S, HE C R. Water-enhanced plastic deformation in felsic rocks[J]. Science China: Earth Sciences, 2013, 56(2):203-216. DOI URL
[33]	HAN L, ZHOU Y S, HE C R, et al. Sublithostatic pore fluid pressure in the brittle-ductile transition zone of Mesozoic Yingxiu-Beichuan fault and its implication for the 2008 M_w 7.9 Wenchuan earthquake[J]. Journal of Asian Earth Sciences, 2016, 117:107-118. DOI URL
[34]	BÜRGMANN R, DRESEN G. Rheology of the lower crust and upper mantle: evidence from rock mechanics, geodesy, and field observations[J]. Annual Review of Earth and Planetary Sciences, 2008, 36(1):531-567. DOI URL
[35]	DRUIVENTAK A, TREPMANN C A, RENNER J, et al. Low-temperature plasticity of olivine during high stress deformation of peridotite at lithospheric conditions: an experimental study[J]. Earth and Planetary Science Letters, 2011, 311(3/4):199-211. DOI URL
[36]	DRUIVENTAK A, MATYSIAK A, RENNER J, et al. Kick-and-cook experiments on peridotite: simulating coseismic deformation and post-seismic creep[J]. Terra Nova, 2012, 24(1):62-69. DOI URL
[37]	周永胜, 何昌荣. 汶川地震区的流变结构与发震高角度逆断层滑动的力学条件[J]. 地球物理学报, 2009, 52(2):474-484.
[38]	韩亮, 周永胜, 姚文明. 中地壳断层带内微裂隙愈合与高压流体形成条件的模拟实验研究[J]. 地球物理学报, 2013, 56(1):91-105.
[39]	WANG K, HU Y, HE J. Deformation cycles of subduction earthquakes in a viscoelastic Earth[J]. Nature, 2012, 484(7394):327-332. DOI URL
[40]	PEÑA C, HEIDBACH O, MORENO M, et al. Impact of power-law rheology on the viscoelastic relaxation pattern and afterslip distribution following the 2010 M_w 8.8 Maule earthquake[J]. Earth and Planetary Science Letters, 2020, 542:116292. DOI URL
[41]	PAPA S, PENNACCHIONI G, MENEGON L, et al. High-stress creep preceding coseismic rupturing in amphibolite-facies ultramylonites[J]. Earth and Planetary Science Letters, 2020, 541:116260. DOI URL
[42]	OKUDAIRA T, JERÁBEK P, STÜNITZ H, et al. High-temperature fracturing and subsequent grain-size-sensitive creep in lower crustal gabbros: evidence for coseismic loading followed by creep during decaying stress in the lower crust?[J]. Journal of Geophysical Research: Solid Earth, 2015, 120(5):3119-3141. DOI URL
[43]	CAMPBELL L R, MENEGON L. Transient high strain rate during localized viscous creep in the dry lower continental crust (Lofoten, Norway)[J]. Journal of Geophysical Research: Solid Earth, 2019, 124(10):10240-10260. DOI URL
[44]	TARLING M S SMITH S A F, VITI C,, et al. Dynamic earthquake rupture preserved in a creeping serpentinite shear zone[J]. Nature Communications, 2018, 9:3552. DOI URL
[45]	BESTMANN M, PENNACCHIONI G, NIELSEN S, et al. Deformation and ultrafine dynamic recrystallization of quartz in pseudotachylyte-bearing brittle faults: a matter of a few seconds[J]. Journal of Structural Geology, 2012, 38:21-38. DOI URL
[46]	张豫宏, 周永胜, 姚文明, 等. 水对Carrara大理岩强度和变形机制影响的实验研究[J]. 地震地质, 2017, 39(1):54-66.
[47]	RYBACKI E, EVANS B, JANSSEN C, et al. Influence of stress, temperature, and strain on calcite twins constrained by deformation experiments[J]. Tectonophysics, 2013, 601:20-36. DOI URL
[48]	PEC M, STÜNITZ H, HEILBRONNER R. Semi-brittle deformation of granitoid gouges in shear experiments at elevated pressures and temperatures[J]. Journal of Structural Geology, 2012, 38:200-221. DOI URL
[49]	PEC M, STÜNITZ H, HEILBRONNER R. et al. Semi-brittle flow of granitoid fault rocks in experiments[J]. Journal of Geophysical Research: Solid Earth, 2016, 121(3):1677-1705. DOI URL
[50]	牛露, 周永胜, 姚文明, 等. 高温高压条件下彭灌杂岩的强度对汶川地震发震机制的启示[J]. 地球物理学报, 2018, 61(5):1728-1740.
[51]	周永胜, 何昌荣, 杨恒. 水对下地壳基性岩脆塑性转化影响的实验研究[J]. 地震地质, 2004, 26(3):472-483.
[52]	ZHANG P Z, WEN X Z, SHEN Z K, et al. Oblique, high-angle, listric-reverse faulting and associated development of strain: the Wenchuan earthquake of May 12, 2008, Sichuan, China[J]. Annual Review of Earth and Planetary Sciences, 2010, 38(1):353-382. DOI URL
[53]	ZHANG P Z. Beware of slowly slipping faults[J]. Nature Geoscience, 2013, 6(5):323-324. DOI URL
[54]	ZHANG P Z. A review on active tectonics and deep crustal processes of the Western Sichuan region, eastern margin of the Tibetan Plateau[J]. Tectonophysics, 2013, 584:7-22. DOI URL
[55]	周永胜, 蒋海昆, 何昌荣. 不同温压条件下居庸关花岗岩脆塑性转化与失稳型式的实验研究[J]. 中国地震, 2002, 18(4):389-400.
[56]	MITCHELL T M, TOY V, DI TORO G, et al. Fault welding by pseudotachylyte formation[J]. Geology, 2016, 44(12):1059-1062. DOI URL
[57]	PROCTOR B, LOCKNER D A. Pseudotachylyte increases the post-slip strength of faults[J]. Geology, 2016, 44(12):1003-1006. DOI URL