| 地震机理的地球系统科学研究及预测实践 |
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| 引用本文： | 曾佐勋,陈志耕,鲁成东,杨屿,陈康力,向世民,代青沁,张骏,邓延廷,付燕,杜秋姣,刘立林,杨巍然.地震机理的地球系统科学研究及预测实践[J].地学前缘,2021,28(6):263-282. |
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| 作者姓名： | 曾佐勋 陈志耕 鲁成东 杨屿 陈康力 向世民 代青沁 张骏 邓延廷 付燕 杜秋姣 刘立林 杨巍然 |
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| 作者单位： | 1.中国地质大学(武汉) 地球科学学院, 湖北 武汉 430074;2.中国地质大学(武汉) 华中构造力学研究中心, 湖北 武汉 430074;3.教育部三峡库区地质灾害研究中心 防灾减灾联合研究中心, 湖北 武汉 430074;4.中国四川省达州市自然资源和规划局, 四川 达州 635000;5.长江三峡勘测研究院有限公司(武汉), 湖北 武汉 430073;6.中国地震局 大连地震台, 辽宁 大连 116000;7.中国地质大学(武汉) 华中构造力学研究中心 松原地震监测站, 吉林 松原 131100;8.中国地质大学(武汉) 数理学院, 湖北 武汉 430074 |
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| 基金项目： | 国家“985”创新平台建设项目子课题“地震及其次生地质灾害研究”; 中国地质调查局项目(12120114002201); 国家自然科学基金项目(41230206) |
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| 摘 要： | 本文提出了一个新的地震机理模型:高温高压高导低速流变体震源腔(简称震源腔)与闭锁断层组合模型。高温高压下的软流圈物质在复杂相变空间中,受到温度场中的异重流作用和受迫振动作用而形成深源震源腔。随着软流圈物质上涌, 幔汁在温度差和压力差驱使下,涌入地壳中的物理空间,形成浅源地震震源腔。由于温度升高使得腔体内岩石部分熔融或全部熔融,释放出大量气液流体,拓展腔体空间范围,同时提升腔体内压。当腔体内部有效压力(即内压与上覆地壳压力之差)达到腔体边缘或者上方与脆性活动断层交会部位的岩石破坏强度时,震源腔便进入临界状态。当软流圈物质上涌继续向腔体内供能,或者由于星体连线在震源区造成触发作用,便引起震源腔的隐蔽爆炸,即隐爆,释放腔体内部积累的能量,同时释放区域构造应力场作用于闭锁断层积累的应变能。 腔体隐爆释放能量与腔体规模正相关。闭锁断层释放应变能与闭锁断层规模、闭锁区大小以及区域构造应力场强度相关。震源腔与脆性活动断层交会部位,是潜在震源位置。多年观测资料表明,震源腔从进入临界状态到隐爆,一般经历1~13天,平均7天。长期观测表明,潜在震中区在震前经常出现干旱、气温升高、海温升高、大量水汽释放等异常现象。通过超低频地震仪监测、重力波作用于水汽形成的地震云的观测、次声波的监测、卫星重力异常反映的高程面垂向震荡监测、以及地基卫星导航系统地面升降监测等,都显示出震源腔进入临界状态后的胀缩震荡引起震中及其外围地面的垂向振动。文中还给出了震源腔体隐爆遗迹的直接证据。
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| 关 键 词： | 地震机理 高温高压高导低速流变体震源腔 闭锁断层 地震前兆 地震预测 地震云 地球系统科学 |
| 收稿时间： | 2021-08-29 |
Earth system science research on earthquake mechanisms:Theory and validation of a new model |
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| ZENG Zuoxun,CHEN Zhigeng,LU Chengdong,YANG Yu,CHEN Kangli,XIANG Shimin,DAI Qingqin,ZHANG Jun,DENG Yanting,FU Yan,DU Qiujiao,LIU Lilin,YANG Weiran.Earth system science research on earthquake mechanisms:Theory and validation of a new model[J].Earth Science Frontiers,2021,28(6):263-282. |
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| Authors: | ZENG Zuoxun CHEN Zhigeng LU Chengdong YANG Yu CHEN Kangli XIANG Shimin DAI Qingqin ZHANG Jun DENG Yanting FU Yan DU Qiujiao LIU Lilin YANG Weiran |
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| Abstract: | A combined model of seismic source cavity and latching fault for earthquake mechanism is proposed. Deep seismic source cavities are formed by the anomaly gravity flow and forced vibration of the high temperature, high pressure asthenosphere materials in the complex phase transition space of the temperature field. It is common that the mantle fluids, driven by temperature and pressure differences, are transferred from mantle to crust to form source cavities for shallow earthquakes. Due to the temperature rise, the continuous partial and/or full melting of the wallrocks cause the cavity to expand, increasing the pressure inside the cavity. When the effective pressure (i.e., the difference between the internal pressure and the pressure of overlying crust) inside the cavity reaches the failure strength of wall rock at the edge or top of the cavity where wall rock is connected to the relatively brittle active fault(s), the cavity comes to a crucial state. When the asthenosphere continues to supply energy to the cavity, or when the cavity is triggered by earth tide resulted from the alignment of the celestial bodies to the source region, cryptoexplosion occurs to release the energy accumulated in the cavity plus the strain energy accumulated from regional tectonic stress field acting on the latching active fault(s). In this model, the intracavity energy released from cryptoexplosion is positively correlated with the cavity size, while the released strain energy is related to the size and asperity of the fault(s) as well as to the intensity of the regional tectonic stress field. The junction between the source cavity and the relatively brittle active fault(s) is a potential hypocenter of the impending earthquake. Source cavities generally develop in 1 to 13 days, averaging 7 days, from entering the crucial state to cryptoexplosion. After long-term observations we theorize that the abnormal phenomena, such as drought, temperature rise, sea surface temperature rise and water vapor release, often occur in the potential earthquake area before the earthquake. Direct evidence for the seismic source cavity cryptoexplosion are also introduced.|||Based on long-term observations and the seismic source cavity model, we give full affirmation to seismic clouds which have long been denied by seismological and meteorological circles. We consider that the gravitational wave generated by the cavity oscillation in the air, and the magnetic field induced by the eddy flow of fluid in the cavity acting on water vapor, are the physical mechanism of the formation of seismic clouds. Here we show the satellite images of releasing aqueous vapour prior to the M 7.0 Haiti earthquake on January 13, 2010, the M 8.2 Gorkha (Nepal) earthquake on April 25, 2015, and the M 7.0 Jiuzhaigou earthquake on August 8, 2017. By use of seismic tomography technique, the shape and size of the seismic source cavity for the M 8.0 Wenchuan giant earthquake (May 12, 2008) were determined. We found that the hypocenter of the Wenchuan earthquake lies at the junction between the top of the source cavity and the Longmenshan brittle active faults. We performed statistical analysis on the gravity disturbance data of the Jiuzhaigou earthquake area and its vicinity, collected during the 12 years since January 1, 2002, and on the catalogue of the area's earthquakes equal or above M 3.0. The results show that the equivalent elevation amplitude change attributable to gravity anomaly was 3.9 cm before the M 6 earthquake, and the magnitude of earthquake was proportional to the magnitude of elevation oscillation by statistical comparison. Based on the tectonic stress field obtained from 108 fault plane solutions for the Bohai Bay and its periphery, we found that there are abnormal stress fields above and to the northeast side of the source cavities in both the Tangshan and Haicheng earthquakes. This points to the effect of high pressure in the source cavity on regional tectonic stress field.|||By using the abnormal sea surface temperature, ZENG Zuoxun successfully predicted the epicenter location of the M 6.7 earthquake on May 1, 2021 off the coast of Honshu Island, Japan. Using drought and temperature anomalies, he correctly predicted two days in advance the epicenter location of the M 4.8 Chuxiong earthquake on June 24, 2021 in Yunnan Province.|||Based on the frequency characteristics of the geoelectric field generated by the eddy flow of ions in the crucial state of the cavity, we developed a DD108 geoelectric instrument. With the single station observation we can predict (within 1-13 days after the occurrence of the anomaly, averaging 7 days) the occurring time and the magnitude of a coming earthquake. Some examples are shown in the paper, including the M 7.0 Jiuzhaigou earthquake in 2017, and the M 7.4 Qinghai Maduo and M 7.1 Mexico earthquakes in 2021. |
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| Keywords: | earthquake mechanism high temperature high pressure seismic source cavity with high conductivity and low velocity rheid latching fault earthquake precursor earthquake prediction earthquake cloud earth system science |
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