Artificial intelligence in seismology:Advent,performance and future trends

Realistically predicting earthquake is critical for seismic risk assessment,prevention and safe design of major structures.Due to the complex nature of seismic events,it is challengeable to efficiently identify the earthquake response and extract indicative features from the continuously detected seismic data.These challenges severely impact the performance of traditional seismic prediction models and obstacle the development of seismology in general.Taking their advantages in data analysis,artificial intelligence(AI) techniques have been utilized as powerful statistical tools to tackle these issues.This typically involves processing massive detected data with severe noise to enhance the seismic performance of structures.From extracting meaningful sensing data to unveiling seismic events that are below the detection level,AI assists in identifying unknown features to more accurately predicting the earthquake activities.In this focus paper,we provide an overview of the recent AI studies in seismology and evaluate the performance of the major AI techniques including machine learning and deep learning in seismic data analysis.Furthermore,we envision the future direction of the AI methods in earthquake engineering which will involve deep learning-enhanced seismology in an internet-of-things(IoT) platform.     

LusTRE: a framework of linked environmental thesauri for metadata management

The paper illustrates a Linked Thesaurus Framework for the Environment, named LusTRE, to facilitate data sharing across different environmental disciplines. It provides a knowledge infrastructure of multilingual thesauri and code lists, interlinking them so that they can be used as one integrated linked data source. This multilingual thesaurus is published according to the Linked Data Best Practices and supports metadata compilation and data discovery for describing and finding Environmental geodata. A human readable web interface is provided for the exploitation of LusTRE as well as a set of web services for programmatic access to the knowledge infrastructure. LusTRE has been exploited within the European directive INSPIRE and SEIS piloting testbeds implemented within the EU project eENVplus in order to support cross-border and cross-domain data sharing. It is aimed at supporting multilingual data search and query refinement. In order to show how interlinked content can help users to more easily express metadata within Spatial Data Infrastructures (SDI), LusTRE web services have been integrated within existing metadata editors and geoportals.     

川藏铁路通麦?鲁朗段浅层结构背景噪声成像

为探明川藏铁路通麦?鲁朗段浅层地质结构特征,有效评估铁路沿线地质灾害风险,保障铁路设施安全运转,基于短周期密集台阵波形数据利用背景噪声层析成像技术获得了浅地表高分辨率的S波精细速度结构,并结合地质调查结果,精确判断沿线断层几何形态及活动特征.S波速度结构和地质调查结果显示沿线低速区和断层分布有很好的对应关系,断裂F1~F6较好地控制了下方低速区的几何形态.结合地质及地震资料可推断:（1）米林Ms6.9地震发震构造可能属于一条由一系列叠瓦状和背冲式断裂组成的断裂体系,该断裂体系的地震活动存在不断向北西端发育的趋势,地震危险性较高.在断裂体系北西端的拉月隧道,未来可能有较强的地震活动性.（2）嘉黎断裂南支西兴拉断裂在剖面处属于隐伏断裂,F5和F6可能都属于贡日嘎布曲分支,呈高角度W倾,强烈的壳内破碎带特征,可能与嘉黎断裂不断地高角度右旋逆冲剪切运动有关.（3）研究区密集的断裂控制着地下热流循环,高温流体的溶蚀作用加剧了构造作用中岩体的破碎程度,降低了岩体稳定性,易引发多种类型的地质灾害;因此,川藏铁路通麦?鲁朗段应配备能有效应对地质灾害的监测预警系统及应急机制,保障隧道及铁路设施的正常运转.      

宽频带数字地震观测数据子库

宽频带数字地震观测数据库是以Windows98,MS Access97数据库软件，个人Web服务器PWS（Personal Web Server),ODBC(Open Data Base Connector)驱动程序为基础建立的。它采用网页与数据库接口的形式实现了数据网上发布与数据存储的完全分离。该子库具有运行速度快，操作简便及安全性强等优点。数据库收录了“九五”以前国土资源部（原地质矿产部）系统天然地震临时台网观测的数据约45GB。可供从事地球深部构造研究、天然地震监测等方面的研究者按共享协议使用。     

“OneGeology计划”及其在中国研究新进展

"OneGeology计划"中文名为"同一个地质计划"、"地质一体化计划"或者"世界大地质计划",其目的是建立一个包含多个国际组织和国家的地质调查机构参与的全球数字地质图共享系统。该计划应用J2EE和WebGIS技术,以网络为平台提供各种比例尺的地质图,参与该项目的国家通过发布基于开放地理信息系统协会(OGC)标准的网络服务并将访问接口注册到OneGeology门户网站实现地质图空间数据的共享。本文以中国新建成的1∶100万国际分幅地质图空间数据库为基础,应用"OneGeology计划"的有关标准和要求,进行数字地质图共享试点研究,为建立中国小比例尺数字地质图共享系统"OneGeology-China"奠定基础。     

对后续震相的认识促进了地震层析成像的发展

与地震初动震相相比,后续震相包含有更为丰富的地球内部信息,因此逐渐地在地震层析成像研究中得到重视。文中以赵大鹏等最近的层析成像研究为例,介绍了通过增加后续震相到时信息得到的新的层析成像研究成果,包括通过使用反射波,仅用两个地震台站就可以进行地壳成像研究;深度震相到时的增加,拓宽了区域成像范围,成功实现了台网外部层析成像;随着国际地震中心(ISC)提供的更丰富的各种后续震相到时,对后续震相的认识和使用促进了全球体波走时成像的发展和对地球深部结构及动力学过程的认识。另一方面,地震学相关领域的进步,使得更多的后续震相能够被拾取并被应用到成像研究中,这将大大提高对地震波形信息的挖掘,提高对研究地区下三维结构的认识,极大地促进地震层析成像学的发展。     

利用地震波场参数探讨岩性非均质的分布

本文利用 Ｓ Ｔ Ｍ 地区二维地震资料中提取中油组的主振幅参数与岩性参数进行相关拟合,并依据岩性分析资料和调谐厚度将其划分为三个区带：低振幅带、正常振幅带和异常高振幅带。综合分析油气测试结果、岩性统计资料后认为,其中的异常高振幅带是结构疏松、孔隙发育、连通性好的均质储层分布区,并从合成记录和理论模型正演结果对上述结论进行了证实。结合沉积相分析成果,将该地区的岩性非均质划分为三种类型,后期在优质储层均质区块中钻探获得了高产工业油气流,从而证实了从地震角度划分岩性非均质分布,不仅是可行的,而且是准确的。该方法不仅拓宽了地震资料的应用范围,也为寻找有利油气富集区提供了一种行之有效的方法。     

应用三维共炮点P波反射数据反演煤系地层参数

常规地震处理方法很难从反射时距中将速度与界面深度、走向和倾角等地层参数分离开来，这使得许多陡倾界面发育的构造复杂区反射成像质量不高。发挥三维地震勘探反射面接收的优势，利用三维倾斜界面P波反射仍具有双曲面时距的特点，导出界面深度、走向、倾角及P波速度的反演解，该反演解是唯一的。经实际资料验证，用网格接收面中任两条测线的时距可以得到全部速度和界面参数。这对于三维叠加偏移处理和提高成像质量有直接的影响。     

Exploring the seismic expression of fault zones in 3D seismic volumes

Mapping and understanding distributed deformation is a major challenge for the structural interpretation of seismic data. However, volumes of seismic signal disturbance with low signal/noise ratio are systematically observed within 3D seismic datasets around fault systems. These seismic disturbance zones (SDZ) are commonly characterized by complex perturbations of the signal and occur at the sub-seismic (10 s m) to seismic scale (100 s m). They may store important information on deformation distributed around those larger scale structures that may be readily interpreted in conventional amplitude displays of seismic data. We introduce a method to detect fault-related disturbance zones and to discriminate between this and other noise sources such as those associated with the seismic acquisition (footprint noise). Two case studies from the Taranaki basin and deep-water Niger delta are presented. These resolve SDZs using tensor and semblance attributes along with conventional seismic mapping. The tensor attribute is more efficient in tracking volumes containing structural displacements while structurally-oriented semblance coherency is commonly disturbed by small waveform variations around the fault throw. We propose a workflow to map and cross-plot seismic waveform signal properties extracted from the seismic disturbance zone as a tool to investigate the seismic signature and explore seismic facies of a SDZ.     

JAVA Applet在ASP组件WEBGIS系统中的应用

在Internet日益繁荣的今天，WEBGIS已经成为GIS领域研究的热点。笔者所在的研究小组提出了一种基于ASP组件技术的WEBGIS解决方案。该方案具有运行速度快、功能强大、与浏览器绝对平台无关等优点，但在客户端人机交互这一方面存在不足。为此，引入JAVA Applet作为系统客户端技术的补充，利用JAVA Applet客户端运行、与平台无关、人机交互功能强等优点，来实现运行速度快、功能强大、人机交互好的具有实用价值的WEBGIS。     

Application of mathematical and machine-computing methods to certain problems in geology and geophysics

Mathematical interpretation of data for computer (EDP) processing has not been studied, developed, and applied, as consistently in geology, as it has been applied to problems in seismology, seismic exploration, and oceanic hydroacoustics. The trend in “mathematical geology” is to reduce complex processes to simple models, thereby controlling the large number of accidental phenomena and statistically determining their relationships. The trend in geology is the construction and testing of expectancy models and development of “response-models” for processing experimental material by means of speeial program systems, e.g. for determining “geologic environment” and for analyzing paragenesis. -- IGR Staff.     

Bayesian estimation of reservoir properties—effects of uncertainty quantification of 4D seismic data

This paper shows a history matching workflow with both production and 4D seismic data where the uncertainty of seismic data for history matching comes from Bayesian seismic waveform inversion. We use a synthetic model and perform two seismic surveys, one before start of production and the second after 1 year of production. From the first seismic survey, we estimate the contrast in slowness squared (with uncertainty) and use this estimate to generate an initial estimate of porosity and permeability fields. This ensemble is then updated using the second seismic survey (after inversion to contrasts) and production data with an iterative ensemble smoother. The impact on history matching results from using different uncertainty estimates for the seismic data is investigated. From the Bayesian seismic inversion, we get a covariance matrix for the uncertainty and we compare using the full covariance matrix with using only the diagonal. We also compare with using a simplified uncertainty estimate that does not come from the seismic inversion. The results indicate that it is important not to underestimate the noise in seismic data and that having information about the correlation in the error in seismic data can in some cases improve the results.     

波形分类技术在滨海断鼻南部沉积相研究中的应用

波形分类技术综合利用了三维地震资料包含的各种信息,真实的反映了地层岩石物性在横向上的变化,可以满足隐蔽油气藏勘探阶段对沉积微相研究精度的要求。时窗的合理选取,分类数等相关参数的调节对于波形分类结果十分重要。以歧口凹陷滨海断鼻南部沉积微相的研究为例,说明该方法是行之有效的。     

利用时空校正方法做山区地震勘探静校正

在山区地震勘探中,由于地表高差起伏剧烈,不仅对地震波旅行时造成很大影响,而且导致水平叠加时共反射点与共中心点产生较大偏差,影响了叠加精度。为解决这一问题,提出了时空校正的方法。它是根据几何地震学的基本原理,将炮点和检波点的位置沿射线路径校正到基准面上地震波入射和出射的位置,以去除地表起伏引起的反射点与共中心点的偏差,并对基准面以上的射线路径进行地震波旅行时间校正。处理效果表明,该方法为解决山区地震勘探的静校正问题提供了一种新的思路。      

波场变换方程的数值计算

对瞬变电磁法 (TEM)测量数据作波场变换,可以实现TEM数据的拟地震成像解释,其中,虚拟波动场波形展宽现象是阻碍这一应用的关键问题。本文采用Tikhonov正则化算法和选取正则因子的L准则,对具有解析结果的波场变换方程进行了数值求解。数值计算表明,由于数值计算引入的展宽是虚拟波动场波形展宽的主要因素,因此,减小数值求解波场变换方程时所引入的波形展宽,应当是波场变换方程应用研究的重要问题之一。      

晶质岩石的地震波性质及其地质、地球物理意义

人类有关地球内部物质成份、结构和物理状态的认识绝大多数来自于地震波的资料,而地震波资料的正确解释又离不开岩石地震波性质的高温高压实验研究。地壳和地幔岩石的地震波性质和各向异性是当今世界地学前沿研究的一项重要内容,该领域横跨了地震学、岩石物理学和构造地质学,在过去一段时间里非常活跃并取得许多重要的成果。本文仅将作者近年来研究岩石地震波性质（例如,岩石波速滞后性,地震波速随围压的变化规律,纵、横波速之间的关系,泊松比等）的部分进展做一简扼的综述,并谨以此纪念已故中国科学院院士张文佑先生诞辰100周年。     

地球观测数据卫星分发系统发展综述

地球观测数据卫星分发系统(GEONETCast)借助通信卫星,把从地面站点、航空和航天平台获取的观测数据、产品传送给广大的用户。GEONETCast当前由CMACast,EUMETCast和GEONETCast Americas 3个区域系统组成,作为地球观测组织(GEO)提出的全球综合地球观测系统(GEOSS)的全球地球观测数据和信息卫星分发系统,旨在满足9个社会受益领域的用户需求。GEONETCast建立在现有区域系统之上,利用GEO的协调机制,共同确定GEONETCast系统的整体计划和要求。各区域系统在科研项目和业务建设的支持下,不断发展完善。未来要保障GEONET-Cast健康、良性和可持续的业务运行,还需要加强4个方面的工作:①区域系统之间的互相通信;②保持GEONETCast的开放性和动态性,发展更多的数据提供者提供地球观测数据;③发展更多的数据使用者;④数据政策。     

氡、氦等气体地球化学在地震科学研究中的进展

系统回顾了氡、氦的气体地球化学特征及其在地震科学研究中的应用情况。在分析氡、氦等地下气体在地壳中浓度变化的影响因素基础上,总结出氡、氦等地下气体浓度变化具年变（或日变）规律,且受多种因素诸如其自身的地球化学行为、气候条件、地质构造及区域应力场等的综合影响。归纳了近30年来在氡、氦的理论和实验研究以及氡异常的形成机理研究方面所取得的进展。氡、氦等地下气体在地震监测预报及基础研究方面日益发挥出越来越重要的作用,但对其自身的认识还远远不够,提出了今后应在氡、氦等地下气体的异常迁移、实验研究、资料处理过程中对干扰因素的排除以及开展深部气体运移与地震活动的关系等方面开展研究的建议。