[关键词]
[摘要]
地震、形变、火山气体地球化学等观测结果表明2002~2005年长白山天池火山经历了1次扰动事件。长白山站地震台(CBS台)记录到了扰动事件前后连续稳定的宽频带地震观测资料。前人的观测研究结果认为长白山天池火山扰动期间的火山地震类型主要为构造型火山地震,伴随少量的谐频型地震。本文通过匹配滤波技术,对1999~2007年扰动事件前后CBS台单台三分量地震观测数据进行模板扫描,获得3763个清晰的火山地震事件,其中谐频(HS)事件125个,构造(VT)事件3618个,并发现长周期(LP)事件20个。进而将火山扰动期间火山地震事件分为3种类型:构造型事件、长周期事件和谐频型事件,并提出2002~2005年长白山天池火山扰动机制模型:深源地震-火山能量传递模型,即汪清深源地震能量释放和传递,引发长白山火山区岩石圈应力状态波动。地幔岩浆房受应力干扰后,岩浆通道打开,少量岩浆侵入地壳岩浆房。岩浆混合脱气导致地壳岩浆房升压,引起顶部岩石微破裂,产生构造型火山地震,气体和流体填充这些裂隙,从而产生LP和HS型火山地震事件。
[Key word]
[Abstract]
The observation of earthquake,deformation and volcanic gas geochemistry show that Changbaishan volcano experienced an unrest from 2002 to 2005. Before and after the volcanic unrest,station CBS recorded continuous and stable broadband seismic data. According to the previous observation results,the main type of volcanic earthquake during the Changbaishan volcanic unrest is volcanic tectonic earthquake,accompanied by a small number of harmonic earthquakes. In this paper,based on the matched-filter technique,the three component seismic data before and after the volcanic unrest from 1999 to 2007 from Changbaishan Volcano Observatory were scanned by template,and 3763 clear volcanic seismic events were obtained,including 125 harmonic spectra(HS)events,3618 volcanic tectonic(VT)events,and 20 long-period(LP)events. The volcanic earthquake events during the volcanic unrest can be divided into three types:volcanic tectonic events,long-period events and harmonic spectra events. A model of "energy transfer between deep earthquakes and volcanoes" is proposed for Changbaishan volcanic unrest mechanism from 2002 to 2005 as follows. First,Wang Qing deep-focus earthquake energy release and transfer,causing the lithospheric stress state fluctuation in Changbaishan volcanic area. Then,after the mantle magma chamber is disturbed by stress,the magma channel opens and a small amount of magma intrudes into the crust magma chamber. Finally,mixed degassing of magma leads to the pressure rise of magma chamber in the crust,which leads to the micro fracture of the top rock,resulting in volcanic tectonic earthquake. When gas and fluid fill these fissures,LP and HS type volcanic earthquake events occur.
[中图分类号]
P315
[基金项目]
国家自然科学基金项目(41572319)、地震科技星火计划攻关项目(XH19009)共同资助