2010年玉树Ms7.1级地震裂缝充填物光释光测年
发布时间：2018-07-31 08:10
【摘要】：古地震的年代确定是重建强震活动历史、预测未来地震趋势的重要依据(杨会丽,2014)。光释光方法是测定古地震事件年代方法中的一种。由于古地震造成的是快速混杂堆积物,其信号的回零程度不一。所以对于光释光运用于古地震测年的适应性引起过不少学者的争论。2010年4月14日,位于甘孜-玉树断裂带上的玉树县发生了Ms7.1级大地震,这提供了很好的研究地震裂缝充填物光释光信号回零程度的机会。本文研究采集了在此次地震裂缝上的充填物及同深度的原生堆积层的样品,采用光释光对石英进行测年,并将得到的测年结果进行对比,分析充填物的晒退情况。并由此探讨了光释光测年在古地震测年中的适应性。从本次研究工作中得到以下结果和认识:1.隆宝湖西1号探槽充填物样品LBHX1-4、LBHX1-5的年代结果分别是1.95±0.08ka、2.50±0.10ka,同深度的原生堆积层样品LBHX1-2、LBHX1-6的年代结果分别是2.53±0.10ka、1.95±0.07ka。充填物年龄与同深度的原生堆积层的年龄在误差范围内基本一致。探槽原生堆积层自上而下,LBHX1-1、LBHX1-2和LBHX1-3的年代结果分别为1.65±0.09ka、2.53±0.10ka、2.81±0.3ka,有明显的层序性,年代结果从原生堆积层顶部越往下越老。2.隆宝湖西2号探槽的充填物从上到下依次为LBHX2-1、LBHX2-2、LBHX2-3,年代结果分别为1.29±0.07ka、2.83±0.1ka、4.15±0.3ka,充填物从上到下也有较好的层序性,年代结果从崩积楔顶部越往下越老。3.可能是母质比较老的缘故,纳利库探槽和禅古水电站探槽的充填物年龄达到了4.68±0.3ka(NLK1-2)、和17.75±0.53Gy(CGSDZ1-2)。采集类似于纳利库和禅古水电站探槽的充填物样品来限定60ka以内的古地震年龄可能存在较大的误差。4.隆宝湖西1、2号探槽、纳利库探槽及禅古水电站四个探槽样品的测年结果均表明地震填充物等在2010年地震中曝光不充分。5.隆宝湖西1、2号探槽处于原生堆积状态,充填物及原生堆积层的年代结果小于2.53±0.1ka,在光释光允许误差范围内(5%-10%),采集充填物顶部或同深度原生堆积层的样品来测定25ka以上的古地震年代是适用的。6.由于地震造成的快速沉积物可能存在个别矿物颗粒曝光充分的情况,接下来可以运用单颗粒的方法进行光释光测年,检测出沉积时曝光充分的颗粒,或许可以获得地震发生的确切年龄。
[Abstract]:The dating of paleoearthquakes is an important basis for reconstructing the history of strong earthquakes and predicting the trend of earthquakes in the future (Yang Huili 2014). Photoluminescence method is one of the methods for dating paleoearthquake events. Since the paleoearthquakes caused by the rapid mixed deposits, the signal return to zero varying degrees. Therefore, the adaptability of the application of photoluminescence to paleoseismic dating has caused controversy among many scholars. On April 14, 2010, a large earthquake of magnitude Ms7.1 occurred in Yushu County, located on the Ganzi-Yushu fault zone. This provides a good opportunity to study the degree of return to zero of photoluminescence signal of seismic fracture filling. In this paper, samples of fillers and primary deposits of the same depth on the fractures of this earthquake have been collected, and the age of quartz has been measured by means of photoluminescence, and the results obtained have been compared to analyze the sunburn of the fillers. The adaptability of photoluminescence dating in paleoseismic dating is discussed. From this research work to get the following results and understanding: 1. The dating results of LBHX1-4 and LBHX1-5 in LBHX1-4 and LBHX1-5 of LBHX1-4 and LBHX1-6 in LBHX1-2 and LBHX1-6, respectively, are 1.95 卤0.07ka and 2.53 卤0.10ka1.95 卤0.07ka, respectively. The age of the filling is basically the same as that of the primary deposit of the same depth within the error range. The age results of LBHX1-1 and LBHX1-3 are 1.65 卤0.09ka/ 2.53 卤0.10ka/ 2.81 卤0.3ka. the age result is older and older from the top of the primary accumulation layer to that of LBHX1-2 and LBHX1-3, respectively, and the age result is 1.65 卤0.09kaor 2.53 卤0.10ka/ 2.81 卤0.3ka. the age result is older and older from the top of the primary accumulation layer. LBHX2-1 and LBHX2-2 LBHX2-3 were used in LBHX2-1, LBHX2-2, LBHX2-3, and the results were 1.29 卤0.07kaor 2.83 卤0.1kaor 4.15 卤0.3ka. the filling also had better sequence from top to bottom. It is possible that the filling ages of the Naliku and Chengu grooves are 4.68 卤0.3ka (NLK1-2) and 17.75 卤0.53Gy (CGSDZ1-2). It is possible that there is a large error in determining the paleoseismic age within 60ka by collecting the backfill samples similar to the trenches in Naliku and Zenggu Hydropower stations. The dating results of the first and second grooves in Longbao Lake, Naliku Prospecting Groove and four Prospecting channels in Zenggu Hydropower Station indicate that the seismic fillers were not fully exposed in the 2010 earthquake. The Prospecting trough No. 1 and No. 2 in the west of Longbao Lake is in the state of primary accumulation. The age results of the filling and primary deposits are less than 2.53 卤0.1 ka. within the allowable error of photoluminescence (5-10%), it is suitable to measure the paleoearthquake age above 25ka by collecting samples from the top of the filling or the same depth of the primary accumulation. Because the rapid sediment caused by earthquake may have sufficient exposure of individual mineral particles, we can then use the method of single particle to carry out the photometric dating to detect the fully exposed particles at the time of deposition. It may be possible to obtain the exact age at which the earthquake occurred.
【学位授予单位】：青海师范大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P315.6
，
本文编号：2154965
[Abstract]:The dating of paleoearthquakes is an important basis for reconstructing the history of strong earthquakes and predicting the trend of earthquakes in the future (Yang Huili 2014). Photoluminescence method is one of the methods for dating paleoearthquake events. Since the paleoearthquakes caused by the rapid mixed deposits, the signal return to zero varying degrees. Therefore, the adaptability of the application of photoluminescence to paleoseismic dating has caused controversy among many scholars. On April 14, 2010, a large earthquake of magnitude Ms7.1 occurred in Yushu County, located on the Ganzi-Yushu fault zone. This provides a good opportunity to study the degree of return to zero of photoluminescence signal of seismic fracture filling. In this paper, samples of fillers and primary deposits of the same depth on the fractures of this earthquake have been collected, and the age of quartz has been measured by means of photoluminescence, and the results obtained have been compared to analyze the sunburn of the fillers. The adaptability of photoluminescence dating in paleoseismic dating is discussed. From this research work to get the following results and understanding: 1. The dating results of LBHX1-4 and LBHX1-5 in LBHX1-4 and LBHX1-5 of LBHX1-4 and LBHX1-6 in LBHX1-2 and LBHX1-6, respectively, are 1.95 卤0.07ka and 2.53 卤0.10ka1.95 卤0.07ka, respectively. The age of the filling is basically the same as that of the primary deposit of the same depth within the error range. The age results of LBHX1-1 and LBHX1-3 are 1.65 卤0.09ka/ 2.53 卤0.10ka/ 2.81 卤0.3ka. the age result is older and older from the top of the primary accumulation layer to that of LBHX1-2 and LBHX1-3, respectively, and the age result is 1.65 卤0.09kaor 2.53 卤0.10ka/ 2.81 卤0.3ka. the age result is older and older from the top of the primary accumulation layer. LBHX2-1 and LBHX2-2 LBHX2-3 were used in LBHX2-1, LBHX2-2, LBHX2-3, and the results were 1.29 卤0.07kaor 2.83 卤0.1kaor 4.15 卤0.3ka. the filling also had better sequence from top to bottom. It is possible that the filling ages of the Naliku and Chengu grooves are 4.68 卤0.3ka (NLK1-2) and 17.75 卤0.53Gy (CGSDZ1-2). It is possible that there is a large error in determining the paleoseismic age within 60ka by collecting the backfill samples similar to the trenches in Naliku and Zenggu Hydropower stations. The dating results of the first and second grooves in Longbao Lake, Naliku Prospecting Groove and four Prospecting channels in Zenggu Hydropower Station indicate that the seismic fillers were not fully exposed in the 2010 earthquake. The Prospecting trough No. 1 and No. 2 in the west of Longbao Lake is in the state of primary accumulation. The age results of the filling and primary deposits are less than 2.53 卤0.1 ka. within the allowable error of photoluminescence (5-10%), it is suitable to measure the paleoearthquake age above 25ka by collecting samples from the top of the filling or the same depth of the primary accumulation. Because the rapid sediment caused by earthquake may have sufficient exposure of individual mineral particles, we can then use the method of single particle to carry out the photometric dating to detect the fully exposed particles at the time of deposition. It may be possible to obtain the exact age at which the earthquake occurred.
【学位授予单位】：青海师范大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P315.6
，
本文编号：2154965
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