面向"数字地球"的岩石层三维成像
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摘要
在目前主要是基于大地测量信息和卫星遥感信息而建立的“数字地球”的框架构想中，显然没有充分考虑到地球内部的三维结构及其随时间的变化， 但是另一方面， 要真正实现 “数字地球”构想中的模拟和预测的功能， 这部分信息是必不可少的。以 “数字地球”为考虑问题的参考系， 对地观测的分辨本领问题具有特别重要的意义。近年来， 随着以高新技术为基础的地震学的发展， 地震学在分辨本领方面取得突破性进展， 以宽频带数字地震学为标志的现代地震学的发展使面向“数字地球”的岩石层三维成像成为可能。进行千米精度的探测和年尺度的监视， 并将这些信息整合到 “数字地球”的框架中去， 已经成为现实的技术目标。尽管与１ ｍ 精度和近实时时间尺度的“数字地球”信息相比仍有３～４ 个数量级的差距。这种信息对于地球内部而言却几乎是唯一的和最精确的， 并且对于地球过程的模拟和预测是必不可少的资料。面向“数字地球”的岩石层三维成像的主要应用范围是针对重大工程项目的环境评估和灾害预测。此外， 这些信息还将为地球科学中的跨学科研究提供基本信息。面向“数字地球”的岩石层三维成像的设想包括三个层次： 范围１０２ ｋｍ 尺度、横向１０ ｋｍ 精度、纵向１ ｋｍ 精度， 主要技术依托为宽频
At present,the concept of‘Digital Earth’,which is based on the information from geodesy and remote sensing,has not considered the 3 D structure of the Earth′s interior and its temporal variation.However,such kind of information is crucial for the function of simulation and prediction within ‘Digital Earth’.In the perspective of‘Digital Earth’,the resolution of geophysical observation plays a key role.With the recent development of seismology based on the application of hightechnology,the resolution of seismological observation has been improved to a considerable extent.Broadband digital seismology has made the‘Digital Earth’oriented 3 D mapping of lithospheric structure possible.The kilometer scale observation and the annual scale monitoring as well as the integration of geophysical information into‘Digital Earth’has become a practical technique.Comparing to the meter scale resolution and the near real time monitoring function of‘Digital Earth’,there is still a difference of 3 to 4 orders of magnitudes.On the other hand,however,the geophysical information obtained in this way is unique and almost the most accurate for the Earth′s interior,and crucial for the simulation and prediction of the Earth processes.The main application of the‘Digital Earth’oriented 3 D mapping of lithosphere is to the environmental evaluation of large engineering and the prediction of natural disasters.Moreover,it also served as an information resource for the interdisciplinary studies in Earth sciences.The proposed concept of‘Digital Earth’oriented 3 D mapping of lithospheric structure is composed of three levels:(1)100 km range,10 km horizontal resolution,and 1 km vertical resolution,based on broadband mobile seismic arrays;(2)1 000 km range,100 km horizontal resolution,and 10 km vertical resolution,based on broadband digital regional seismic networks;(3)global range,1 000 km horizontal resolution,and 100 km vertical resolution,based on broadband global digital seismic network.
At present,the concept of‘Digital Earth’,which is based on the information from geodesy and remote sensing,has not considered the 3 D structure of the Earth′s interior and its temporal variation.However,such kind of information is crucial for the function of simulation and prediction within ‘Digital Earth’.In the perspective of‘Digital Earth’,the resolution of geophysical observation plays a key role.With the recent development of seismology based on the application of hightechnology,the resolution of seismological observation has been improved to a considerable extent.Broadband digital seismology has made the‘Digital Earth’oriented 3 D mapping of lithospheric structure possible.The kilometer scale observation and the annual scale monitoring as well as the integration of geophysical information into‘Digital Earth’has become a practical technique.Comparing to the meter scale resolution and the near real time monitoring function of‘Digital Earth’,there is still a difference of 3 to 4 orders of magnitudes.On the other hand,however,the geophysical information obtained in this way is unique and almost the most accurate for the Earth′s interior,and crucial for the simulation and prediction of the Earth processes.The main application of the‘Digital Earth’oriented 3 D mapping of lithosphere is to the environmental evaluation of large engineering and the prediction of natural disasters.Moreover,it also served as an information resource for the interdisciplinary studies in Earth sciences.The proposed concept of‘Digital Earth’oriented 3 D mapping of lithospheric structure is composed of three levels:(1)100 km range,10 km horizontal resolution,and 1 km vertical resolution,based on broadband mobile seismic arrays;(2)1 000 km range,100 km horizontal resolution,and 10 km vertical resolution,based on broadband digital regional seismic networks;(3)global range,1 000 km horizontal resolution,and 100 km vertical resolution,based on broadband global digital seismic network.
引文
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