中国大陆火山监测研究进展

在过去几年里，长白山天池火山观测到了明显的地震活动增加、地表抬升和膨胀以及多种流体化学异常。地震学研究和形变模拟表明，长白山天池火山近年来的活动可能是由其下方的岩浆活动引起的。1993年以来，腾冲火山出现强烈的水热活动。地球化学参数的变化表明，气体源区的深度逐渐增加。火山区存在的震群活动、部分台站观测到的S波阴影区以及地表的缓慢抬升等，指示火山区存在一个岩浆系统。监测研究结果表明，目前我国大陆其他火山的活动性较弱。     

长白山天池火山千年大喷发不同颜色浮岩的岩石化学特征

长白山天池火山大约 1 000年前的大喷发,形成了巨厚的火山碎屑流堆积层,其主要组成是浮岩与火山灰。以往的研究普遍认为其中的浮岩为灰白色,属流纹质。笔者在考察中发现了不少黑色及少量其它颜色的浮岩,系统地采集了各色样品作浮岩化学成分分析,结果表明,灰白色浮岩与黑色浮岩分别为流纹质和粗面质,灰色浮岩属于粗面质但靠近流纹质端元。它们都来源于地壳岩浆房,是岩浆房内不同分异演化阶段的产物,它们同时喷出说明岩浆房内具有分带性及不同性质岩浆的混合     

2-D crustal Poisson′s ratio from seismic travel time inversion in Changbaishan Tianchi volcanic region

Introduction Forward modeling is commonly used in the interpretation of 2D crustal structure with wide-angle seismic reflection/refraction data. But this method not only has mass work and more subjective effects, but also cannot provide quantitative estimates of model parameter error, resolu-tion, and model uniqueness. It also cannot assure that the data consistency is the minimum of par-ticular range. In order to overcome the defects of forward modeling, Zelt and Smith (1992) have developed…     

福建安村金矿地质找矿的再认识

安村金矿地球化学异常规模大，特征好，并具良好的成矿地质背景，以往做了一些地质工作．但找矿尚未突破。文章从火山构造控矿特征入手，通过对相关找矿信息的综合分析研究，初步建立了矿区火山构造控矿模型，在此基础上，优选了3处找矿靶区进行找矿预测评价。     

Liquefied vs stratified sediment mobilization processes: Insight from the South of the Barbados accretionary prism

This paper discusses the nature and origin of subsurface sediment mobilization processes in deep marine clay-rich environments. In the studied area of the southern Barbados accretionary prism, new geophysical acquisitions have emphasized the spectacular widespread development of mud volcanoes that are well-developed along ramp anticlines and along sigmoidal rises with trends that are oblique to the axes of the main folds of the accretionary wedge. On some active mud volcanoes, heat-flow measurements show high positive anomalies related to high fluxes of mud transfer. The mobilized solid fraction expelled by the mud volcanoes does not originate from a unique source bed but from various formations pierced by the mud conduits and is driven by the water phase. The area studied also exhibits trends of structures corresponding to sub-circular massive local uplifts of deformed but well-preserved stratified sediments (turbidites and hemipelagics). No piercing shale diapirs have been encountered in this area. Some of these local uplift structures are complicated by the development of collapses, calderas, and superimposed mud volcanoes. Mud volcanism corresponds fundamentally to fluid displacement (water and gas), whereas massive sedimentary uplift corresponds to large vertical displacements of stratified solid levels but for which the deep cause could be partly the intrusion of mud plugs. Both are dynamic phenomena controlled by the development of overpressure at depth, contributing to sedimentary mobilizations.     

On the devil's tracks: unexpected news from the Foresta ichnosite (Roccamonfina volcano,central Italy)

The Foresta ichnosite is well known for preserving some of the oldest human fossil footprints recorded in Europe so far. This research aims to: i) describe new footprints that are larger than those already reported, some of which form a new trackway that moves in the opposite direction to all the others; ii) announce the discovery of some stone tools also in the surroundings of the Foresta ichnosite. The new results increase the total number of human fossil footprints to at least 81, specify the direction and the number of footprints of Trackway C, and identify three new directions of walking at the site. More compelling and complete estimates of the dimensional range of all ichnological evidence enables us, furthermore, to estimate the number of trackmakers walking on the trampled surface as a minimum of five, one of them likely being an adult male. The general shape of all the recorded footprints suggests that the Foresta trackmakers share some similarities with those at Sima de los Huesos, and belong to the same taxonomical group as the Ceprano skull. All the new evidence enables us to better understand the presence of hominin populations in the Roccamonfina volcano area during the Middle Pleistocene. © 2020 John Wiley & Sons, Ltd.     

长白山天池火山区介质非均匀性

高频S波随着传播距离的增大其均方根(RMS)包络逐渐变宽,我们把这种现象称为S波包络展宽现象.S波传播路径上随机分布的非均匀体对S波的多次前向散射和绕射作用是导致S波包络展宽现象的主要原因,因此可用S波包络展宽现象来研究介质非均匀性.本文采用S波包络峰值延时来对S波包络展宽现象进行量化.S波包络峰值延时定义为S波初至与其均方根包络峰值最大值之间的时间差.本文选用长白山天池火山区的小震记录,运用S波包络峰值延时对长白山天池火山口地区的介质非均匀性进行了评价.结果发现长白山天池火山区呈现强烈的介质非均匀性,在0~2 km深度范围内介质非均匀性表现出南部强北部弱的空间分布特征;在2~5 km深度范围内介质非均匀性的空间分布特征与频率具有相关性;天池火山区介质非均匀性具有明显的多尺度特性;强弱非均匀性接触带,往往是地震频发地带.根据地震与非均匀体在空间分布的相对位置,我们认为火山区介质非均匀性可能反映了火山早期喷发堆积物介质结构的差异.     

Comparison of COSPEC and two miniature ultraviolet spectrometer systems for SO2 measurements using scattered sunlight

The correlation spectrometer (COSPEC), the principal tool for remote measurements of volcanic SO₂, is rapidly being replaced by low-cost, miniature, ultraviolet (UV) spectrometers. We compared two of these new systems with a COSPEC by measuring SO₂ column amounts at Kīlauea Volcano, Hawaii. The two systems, one calibrated using in-situ SO₂ cells, and the other using a calibrated laboratory reference spectrum, employ similar spectrometer hardware, but different foreoptics and spectral retrieval algorithms. Accuracy, signal-to-noise, retrieval parameters, and precision were investigated for the two configurations of new miniature spectrometer. Measurements included traverses beneath the plumes from the summit and east rift zone of Kīlauea, and testing with calibration cells of known SO₂ concentration. The results obtained from the different methods were consistent with each other, with <8% difference in estimated SO₂ column amounts up to 800 ppm m. A further comparison between the COSPEC and one of the miniature spectrometer configurations, the ‘FLYSPEC’, spans an eight month period and showed agreement of measured emission rates to within 10% for SO₂ column amounts up to 1,600 ppm m. The topic of measuring high SO₂ burdens accurately is addressed for the Kīlauea measurements. In comparing the foreoptics, retrieval methods, and resultant implications for data quality, we aim to consolidate the various experiences to date, and improve the application and development of miniature spectrometer systems.     

镜泊湖全新世火山研究成果概述

本文从火山口的形态、分布、火山喷发时代、火山基浪堆积物及火山成因类型等方面概述镜泊湖全新世火山研究成果，指出该火山活动时间为距今5200～5500年，在该火山碎屑物中发现有火山基浪堆积物，该火山成因类型属于单成因火山。     

火山学述评

火山学研究有了长足的进步。笔者总结近些年全球火山学研究各个方面的成果,包括对火山基本概念的新的认识、火山机构、火山的各种分类、火山岩石学和地球化学、火山岩相学、评估火山爆发大小的火山爆发指数、岩石和地球化学分类、各种常量和微量元素区分图、活火山分布与板块构造理论的关系、活火山给人类带来的灾害与利益和活火山的监测、曾经的火山活动与生物毁灭、单成因火山研究等。火山—构造是未来火山学研究的一个方向,通过火山与构造关系的研究以揭示火山的分布和地球的演化。火山喷出的岩浆是其通过地下以岩墙或管道形式为通道运移到地表的结果。中朝边境上的长白山的位置是个特例,应当值得深入的研究。中国分布有许多新生代火山,它们是否为单成因火山、这些火山在成分上是否有演化规律、它们的分布与大地构造的关系等都有待深入和系统的研究。