The M_S6. 1 earthquake was a foreshock-mainshock-aftershock type which occurred in the boundary region between Zogang and Markam counties on August 12,2013. Within 9hours before the main shock seven earthquakes of gre...The M_S6. 1 earthquake was a foreshock-mainshock-aftershock type which occurred in the boundary region between Zogang and Markam counties on August 12,2013. Within 9hours before the main shock seven earthquakes of greater than M_L2. 0 occurred,with a maximum of M_L4. 7. In this paper,the earthquake focal mechanism changing process of the Zogang-Markam M_S6. 1 earthquake sequence is studied by calculating the correlation coefficient of body wave spectral amplitudes,and the result shows that the correlation coefficients of spectral amplitude of foreshocks present high value fluctuation with an average value of 0. 86,which shows that the focal mechanism of foreshocks are similar;and the correlation coefficients of spectral amplitude of aftershocks present low value,which shows that the possibility of a large earthquake is not high after a time.展开更多
On 23 July 2009, a catastrophic debris flows were triggered by heavy rainfall in Xiangshui gully, Kangding county, southwestern China. This debris flow originating shortly after a rainstorm with an intensity of 28 mm ...On 23 July 2009, a catastrophic debris flows were triggered by heavy rainfall in Xiangshui gully, Kangding county, southwestern China. This debris flow originating shortly after a rainstorm with an intensity of 28 mm per hour transported a total volume of more than 480×103 m3 debris, depositing the poorly sorted sediment including boulders up to 2-3 m in diameter both onto an existing debris fans and into the river. Our primary objective for this study was to analyze the characteristics of the triggering rainfall and the debris supply conditions, and to estimate debris-flow volume, mean velocity, and discharge. A comparison with adjacent rain-gage records indicates that debris flows in this setting can be produced in response to as little as 17 mm/hour or 3.5 mm/10-minute of rainfall intensity with relatively lower amount of cumulative antecedent rainfall. The field measurement and the interpretation of the Worldview image indicate that abundant landslides occurred on steep slopes within areas underlain by highly weathered granite. Using empirical equations that combine flow depth and channel slope, the mean velocity and discharge of the debris flow were estimated to be 9.2 m/s and 2150 m3/s, respectively. The results contribute to a better understanding of the conditions leading to catastrophic debris flows.展开更多
基金jointly sponsored by the Special Program of Earthquake Science and Technology of Earthquake Administration of Sichuan Province(LY1302) the National Key Technology R&D Program of China(2012BAK19802)
文摘The M_S6. 1 earthquake was a foreshock-mainshock-aftershock type which occurred in the boundary region between Zogang and Markam counties on August 12,2013. Within 9hours before the main shock seven earthquakes of greater than M_L2. 0 occurred,with a maximum of M_L4. 7. In this paper,the earthquake focal mechanism changing process of the Zogang-Markam M_S6. 1 earthquake sequence is studied by calculating the correlation coefficient of body wave spectral amplitudes,and the result shows that the correlation coefficients of spectral amplitude of foreshocks present high value fluctuation with an average value of 0. 86,which shows that the focal mechanism of foreshocks are similar;and the correlation coefficients of spectral amplitude of aftershocks present low value,which shows that the possibility of a large earthquake is not high after a time.
基金supported by Chengdu Hydroelectric Investigation & Design Institute, the Ministry of Science and Technology of China (Grant No. 2011CB409903)the Research Fund of the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection (Grant No. 119-000022-18 and SKLGP2009Z2004)
文摘On 23 July 2009, a catastrophic debris flows were triggered by heavy rainfall in Xiangshui gully, Kangding county, southwestern China. This debris flow originating shortly after a rainstorm with an intensity of 28 mm per hour transported a total volume of more than 480×103 m3 debris, depositing the poorly sorted sediment including boulders up to 2-3 m in diameter both onto an existing debris fans and into the river. Our primary objective for this study was to analyze the characteristics of the triggering rainfall and the debris supply conditions, and to estimate debris-flow volume, mean velocity, and discharge. A comparison with adjacent rain-gage records indicates that debris flows in this setting can be produced in response to as little as 17 mm/hour or 3.5 mm/10-minute of rainfall intensity with relatively lower amount of cumulative antecedent rainfall. The field measurement and the interpretation of the Worldview image indicate that abundant landslides occurred on steep slopes within areas underlain by highly weathered granite. Using empirical equations that combine flow depth and channel slope, the mean velocity and discharge of the debris flow were estimated to be 9.2 m/s and 2150 m3/s, respectively. The results contribute to a better understanding of the conditions leading to catastrophic debris flows.
