2025年1月7日西藏定日6.8级地震应急产品产出及震源参数初步分析

Emergency Production and Preliminary Analysis of Source Parameters of the M6.8 Earthquake on January 7,2025 in Dingri,Tibet

摘要:

北京时间2025年1月7日9时5分,西藏日喀则市定日县(28.50°,N,87.45°E)发生6.8级地震,震源深度10km。中国地震预警网于震后19s产出首报预警信息;中国地震台网中心(CENC)于震后170s发布自动速报结果,震后13min发布正式速报结果,同时联合多家单位启动地震应急产品产出工作,产出震源参数、地震构造、历史地震、震源机制、震源破裂过程、推测烈度等应急产品。结果显示,本次地震是一次以正断型为主的事件;余震呈SN向展布,长度约85km,震源深度主要集中在5～15km之间。主震以单侧破裂为主,持续时间约25s,破裂长度约65km,最大滑动量为2.3m,破裂可能出露地表。烈度速报结果显示,极震区推测烈度最高达Ⅸ度,与实际调查烈度基本一致。

Abstract:

At 09:05 on January 7,2025(Beijing time),an earthquake of magnitude 6.8 occurred in Dingri,Tibet(28.50°,N,87.45°E),at a depth of 10km. The China Earthquake Early Warning Networks issued an early warning 19 seconds after the earthquake. The China Earthquake Networks Center(CENC)released automatic rapid report results 170 seconds after the earthquake,followed by the official rapid report 13 minutes later. Concurrently,CENC produced emergency products,including source parameters,seismic tectonics,historical earthquakes,focal mechanisms,rupture processes,and estimated intensity. The results indicated that the earthquake was primarily a normal fault event,with aftershocks distributed along a north-south direction over a length of approximately 85km. The focal depth was mainly concentrated between 5km and 15km. The rupture was predominantly unilateral,with a duration of around 25s,a rupture length of approximately 65km,and a maximum slip of 2.3m. The rupture may have reached the surface. The rapid intensity report estimated that the maximum intensity in the affected area reached IX,which aligns closely with the actual investigation results.