大兴安岭焰山、高山火山——一种新的火山喷发型式

在野外地质资料基础上,利用火山形态学方法,探讨了大兴安岭焰山、高山火山的喷发型式。结果表明,大兴安岭哈拉哈河-绰尔河火山群中的焰山和高山火山不同于斯通博利式喷发形成的火山,其早期爆破喷发的火山碎屑形成火山渣锥、空降火山碎屑席和小型火山碎屑流,晚期溢出大量熔岩。两火山具有较高大的锥体(标高200～300m以上),在结构上,松散火山砾、火山弹等构成下部的降落锥,熔结集块岩构成上部的溅落锥。由火山砾和火山灰组成的空降火山碎屑席分布在火山锥体周围。两火山溢出的熔岩经历了从结壳熔岩→翻花石→渣状熔岩的演变。根据喷发产物可推断焰山和高山火山具有以下喷发特征:爆破喷发形成持续的喷发柱→斯通博利式喷发→熔岩喷泉喷溢,其中以持续时间较长的喷发柱区别于典型的斯通博利式喷发。类似焰山、高山火山的喷发特征,在龙岗第四纪火山群、镜泊湖全新世火山群中也都有个例,这是中国大陆火山作用中一种新的喷发型式。     

高密度电法在火山熔岩台地地质调查中的探讨

五大连池火山群,位于大兴安岭隆起、小兴安岭隆起、松辽坳陷所构成的三角区域。三角区域的边缘由三条断裂所围限,即西侧为北北东向的嫩江断裂,东侧为北北东向的孙吴地堑,南侧为东西向的讷谟尔断裂。五大连池坐落在火山熔岩台地上,火山群由坐落在波状平原上的14座火山锥和覆盖面积达800km^2的熔岩流分布构成,其中12座属于第四纪更新世火山,为五大连池旧期火山,新期的老黑山和火烧山属于近代火山。14座火山分别是：药泉山、卧虎山、笔架山、南格拉球山、北格拉球山、东焦得布山、西焦得布山、东龙门山、西龙门山、影背山、莫拉布山、尾山、老黑山、火烧山。其中老黑山、火烧山是在近代1719年至1721年爆发。高密度电法是近些年引入的物探方法,广泛应用于地质调查及工程勘察中。在火山熔岩台地区应用高密度电法勘察熔岩台地厚度、熔岩隧道、熔岩下伏地层,断裂发育等,能取得较好的地质效果。     

中国境内火山存在山崩现象

近日,吉林大学教授刘祥等人在黑龙江五大连池的老黑山、火烧山附近首次辨认出火山爆发时由山崩形成的岩屑崩落堆积。岩屑崩落堆积是火山喷发碎屑堆积物的重要组成部分之一,近年来在世界范围内受到了火山学家的广泛重视。     

五大连池火山群老黑山火烧山熔岩流流动特征及其形成动力过程

从火山灾害的预测预防角度出发，叙述了五大连池火山群老黑山、火烧山近代火山喷发所形成的熔岩流产物——熔岩的分布，表面特征，流动过程。讨论了漫流、溪谷熔岩流和潜流三种流动方式。对结壳熔岩、渣状熔岩、块状熔岩、喷气锥、熔岩遂道等的形成动力过程以及对古地形古环境条件的制约做了深入的讨论，提出新的形成模式和一些新的认识。     

五大连池火山1720-1721年喷发观测记录

存于黑龙江将军衙门档案中的五大连池火山喷发满文史料 (由吴雪娟发现并译成汉文 ) ,详细记载了五大连池火山在 172 0年 1月 14日至 172 1年 3月 18日喷发形成老黑山、172 1年 4月 2 6日至 172 1年 5月 2 8日喷发形成火烧山的全部过程 ,记述了这 2座火山的喷发时间、地点、喷发状态和火山堰塞湖形成以及参加观测的人员情况等各种史实。这是中国历史上迄今为止对火山喷发仅有的一次有组织的观测活动 ,这些记录为火山观测研究提供了珍贵的第一手资料。同时 ,也表明中国是世界上火山观测开展较早的国家之一。以往认为五大连池老黑山、火烧山火山喷发的时间为公元1719— 172 1年 ,实际应为公元 172 0— 172 1年     

五大连池火山带的火山喷发方式及灾害类型

沿科洛—五大连池—二克山NNW向分布的五大连池火山带上分布了约40座第四纪单成因火山。通过野外地质特征结合火山岩年代学数据分析表明,研究区火山活动分为2期:上新世—早更新世期火山活动主要分布在北部的科洛火山区,以熔岩溢流式喷发为主;中更新世—全新世期火山活动分布在整个火山带,爆破式喷发形成大量火山碎屑锥,溢流式喷发产生结壳熔岩、渣状熔岩与块状熔岩,形成广泛分布的熔岩流。野外调查发现了夏威夷型、斯通博利型与强斯通博利型等岩浆爆破式火山喷发的典型堆积剖面,首次发现并报道研究区射汽岩浆型火山喷发堆积剖面。结合火山活动历史与火山地质特征,分析认为五大连池火山带的火山系统仍有再次活动的潜力。基于火山时空分布与喷发特征,文中对五大连池火山带未来可能喷发的方式和危险区进行评估。如若发生强斯通博利型喷发,将形成高度10km的喷发柱,产生的火山灰一般不会对航空运输产生影响;斯通博利型喷发产生的火山碎屑最远可抛射约1km;夏威夷型喷发及溢流式喷发产生的熔岩流是主要的灾害源,计算得出结壳熔岩运移的距离为3. 0～13. 5km,渣状熔岩运移的距离为2. 9～14. 9km;射汽岩浆型喷发产生的基浪速度可达200～400m/s,运移距离≤10km,是潜在的重要灾害类型,应该引起更多重视,并积极进行防范。     

五大连池火山新史料及对火山喷发过程的讨论

本文叙述了新发现的有关五大连池老黑山,火烧山两座近代火山喷发过程的清化清文料档案的主要内容。在此基础上讨论了火山发过程及有关问题,同时评议了这些史料的学术价值．     

五大连池老黑山火烧山火山喷发物及形成的物理过程

以当代火山物理的观点和思路对黑龙江省五大连池老黑山火烧山进行了研究。在旧锥锥体上部发现滞后角砾岩，在其下部坡脚发现有涌浪（ｓｕｒｇｅ）堆积物的存在，对形成过程和机制做了一些解释。     

有珠火山喷发和地震活动

2000年3月31日下午1时10分左右,位于北海道洞斧湖南侧的有珠火山相隔23年后再次喷发。最初喷发是从有珠火山西北山脚开始,烟柱高达3000m以上。之后,位于洞斧湖温泉镇稍往南的金比罗山附近也出现了火山口,它与西北山脚的火山口一起喷发,水蒸气喷泉和小规模的岩浆水蒸气喷泉交替出现,直至现在。山顶部分是直径约1.8km的外轮山,其内部有大有珠、小有珠两个熔岩穹地和1977年喷发产生的有珠新山的潜在熔岩穹地。同时,从西侧山脚到北山脚、东山脚,依次分布着西山、金比罗山、西丸山、明治新山、东丸山的潜在熔岩穹地和有熔岩穹地的昭和新山。首先,…     

吉林龙岗四海火山碎屑物粒度分析与地质意义

四海火山灰是龙岗火山群中的一次火山爆发形成的,这次火山爆发形成的玄武质空降堆积物分别组成金龙顶子火山渣锥和位于金龙顶子火山锥以东的、分布于辉南县红旗林场和靖宇县四海林场一带的低缓开阔的火山碎屑席。通过投点得知金龙顶子火山喷发类型为次布里尼式(Sub-Plinian)喷发,反映金龙顶子火山爆发强度很大。四海火山灰空降碎屑物7个样品的粒度累计频率曲线投点分布范围、集中区域均有较好的一致性,累计频率曲线表明碎屑物在空中搬运与沉降时都经过了类似的重力分选作用。近火口缘样品粗粒碎屑含量较高,随着与火口缘距离的增加,粗粒部分含量明显降低,细粒碎屑含量增加趋势明显。龙岗火山区内其它岩渣锥火山碎屑物粒度分布范围明显宽于四海火山灰粒度分布范围,累积频率曲线斜率较为一致。虽然样品距火山口距离均较近,但也出现了细粒富集程度变缓的现象,反映了龙岗火山区其它火山锥喷发强度明显小于四海火山。对比长白山天池火山碎屑物粒度分布特征发现,天池火山空降堆积物粒度分布斜率变化比较均匀,四海火山灰斜率有明显变化;四海火山灰最大粒度小于长白山天池火山空降堆积物,但是粗粒度碎屑物含量较高。细粒度碎屑物部分累计频率曲线上升趋势较缓,说明金龙顶子火山的喷发     

黑龙江五大连池火山区气体地球化学特征

根据五大连池火山区的气体地球化学特征,分析了二氧化碳气的生成条件和成因,对火山区CO_2的泄出量进行了概算。通过一年定点观测,查明了南泉和二龙眼泉各气体组分的动态变化特征,认为南泉氢和氦于1988年2月～4月出现的大幅度异常和附近的小震活动有关     

Facies architecture and Late Pliocene – Pleistocene evolution of a felsic volcanic island, Milos, Greece

The volcanic island of Milos, Greece, comprises an Upper Pliocene –Pleistocene, thick (up to 700 m), compositionally and texturally diverse succession of calc-alkaline, volcanic, and sedimentary rocks that record a transition from a relatively shallow but dominantly below-wave-base submarine setting to a subaerial one. The volcanic activity began at 2.66±0.07 Ma and has been more or less continuous since then. Subaerial emergence probably occurred at 1.44±0.08 Ma, in response to a combination of volcanic constructional processes and fault-controlled volcano-tectonic uplift. The architecture of the dominantly felsic-intermediate volcanic succession reflects contrasts in eruption style, proximity to source, depositional environment and emplacement processes. The juxtaposition of submarine and subaerial facies indicates that for part of the volcanic history, below-wave base to above-wave base, and shoaling to subaerial depositional environments coexisted in most areas. The volcanic facies architecture comprises interfingering proximal (near vent), medial and distal facies associations related to five main volcano types: (1) submarine felsic cryptodome-pumice cone volcanoes; (2) submarine dacitic and andesitic lava domes; (3) submarine-to-subaerial scoria cones; (4) submarine-to-subaerial dacitic and andesitic lava domes and (5) subaerial lava-pumice cone volcanoes. The volcanic facies are interbedded with a sedimentary facies association comprising sandstone and/or fossiliferous mudstone mainly derived from erosion of pre-existing volcanic deposits. The main facies associations are interpreted to have conformable, disconformable, and interfingering contacts, and there are no mappable angular unconformities or disconformities within the volcanic succession.Electronic Supplementary Material Supplementary material is available for this article at     

喀拉喀托火山喷发过程与巽他海啸成因

介绍了2018年12月22日发生的巽他海峡喀拉喀托火山喷发的过程及其火山监测情况,并提取了欧空局哨兵1A遥感卫星在火山喷发前后的遥感影像,通过遥感影像的对比分析获得了火山锥体的坍塌范围;使用3DAnalyst软件模块对坍塌部分的DEM影像进行分析,计算出海平面以上火山锥体的坍塌体积约为54000000m3,海面以下崩塌锥体体积更加巨大,崩塌导致火山周围水体发生激荡形成海浪,海浪相干传播至周边海岸附近引发了巽他海峡海啸;海啸灾害主要发生在印尼万丹省西冷县和板底兰县西部沿海,与根据火山喷发引发海啸的传播路径推测的受灾地区基本一致。     

2017年全球活动火山时空分布以及阿贡火山喷发前后的形变特征

归纳总结2017年度全球81座活火山的活动情况,共计活动1058座次,平均每周记录20座活火山的活动信息。根据火山潜在喷发的危险性和火山活动的强弱程度对上述火山进行分级描述,火山活动主要反映了地球表层的构造活动,其中大角度俯冲带的弧后火山最为强烈,小角度的俯冲带、拉张裂谷和走滑为主的板块边界火山活动较为平静,火山活动频繁的印度尼西亚岛链是受灾最为严重的区域。预计全球火山活动将进一步加剧,印尼岛链受火山灾害威胁的程度依然较大。位于印尼岛链巴厘岛上的阿贡火山自2017年9月开始活动以来,整个喷发过程极具代表性,监测阿贡火山喷发过程可为全球典型火山喷发事件研究提供参考。     

松辽盆地营城组火山机构-岩相带的地震响应

松辽盆地徐家围子断陷多期次喷发的火山岩在纵向和横向上相互叠置,造成火山岩地震响应特征复杂,影响了对火山岩储层的地震预测精度和地质规律的认识.本文基于钻井和连片三维地震资料,结合区域构造认识,建立了徐家围子断陷营城组火山机构-岩相带的地震响应模式,并利用相干体和地层切片等属性分析技术实现了火山机构-岩相带的空间识别.从火...     

THE VOLCANIC ACTIVITIES AND HAZARD PREDICTION OF WUDALIANCHI VOLCANIC BELT

More than 40 late Cenozoic monogenetic volcanoes formed a volcanic belt striking NNW from Keluo, through Wudalianchi to Erkeshan in NE China. These volcanoes belong to a unified volcano system, namely Wudalianchi volcanic belt(WVB for short). Based on the volcanic evolution history and the nature of monogenetic volcanic system, we estimate that the volcanic system of WVB is still active and has the potential to erupt again. Hence, this paper studied the temporal-spatial distribution and volcanic eruption types to evaluate the possible eruption hazard types and areas of influence in the future. Volcanic field characteristics and K-Ar radiometric data suggest two episodes of volcanism in the WVB, the Pliocene to early Pleistocene volcanism(4.59~1.00MaBP)and the middle Pleistocene to Holocene volcanism(0.79Ma to now). The early episode volcanoes are distributed only in the north of WVB(mainly in Keluo volcanic field), featured by effusive eruption, and mainly formed monogenetic shield, whose base diameter is large and slope is gentle. However, the late episode eruptions occurred over the entire WVB. The explosive eruption in this stage formed numerous relatively intact scoria cones of explosive origin. Meanwhile the effusive eruption formed widely distributed lava flows. Both effusive eruption and explosive eruption are common in WVB. The effusive eruption formed monogenetic shields and lava flows. The resulting pahoehoe lava, aa lava and block lava appeared in WVB. There are three end-member types of explosive eruption driven by magmatic volatile. Violent Strombolian eruption has the highest degree of fragmentation and mass flux, characterized by eruption column. Strombolian eruption has the high degree of fragmentation, but low mass flux, featured by pulse eruption. Hawaiian eruption has low degree of fragmentation, but high in mass flux, generating large scoria cones. In addition, this paper for the first time found phreatomagmatic eruption in WVB, which formed tuff cone. Transitional eruptions are also common in WVB, which have certain characteristics among the end-member eruption types. Besides, certain volcanoes displayed multiple explosive eruption types during the whole eruption span. According to the volcanic temporal-spatial distribution and eruption characteristics in WVB, the potential volcanic hazards in future are constrained. It appears that the violent Strombolian and Strombolian eruption will not have significant impact on aviation safety in the vertical direction. In the radial direction, the ejected volcanic bomb can reach as far as 1km from the vents and the fallout tephra may disperse downwind over a distance ranging from 1~10km. The major hazard of Hawaiian eruption and effusive eruption comes from lava flow, and its migration distance may reach 3.0~13.5km for pahoehoe lava and 2.9~14.9km for aa lava. The base surge in phreatomagmatic eruption can reach a velocity of 200~400m/s, and the migration distance is around 10km. This is a big threat that people should pay more attention to and take precautions in advance. Besides, it is necessary to strengthen the real-time observation of the volcanoes in the WVB, especially those formed in the late episode as well as near the active fault.     

Volcanic Debris-avalanche Deposits of the Laoheishan Volcano and Huoshaoshan Volcano in Wudalianchi

Large amounts of volcanic debris-avalanche deposits, which take the shape of hummocks, are distributed around the peripheries of the Laoheishan volcano and Huoshaoshan volcano in Wudalianchi World Geopark. In earlier times, they were called "satellite volcanoes", namely, freestanding volcanoes. This paper points out that these deposits actually came from the collapse of the cones of these two volcanoes. When the lava flow spilled out at the base of the slope of the cones, the slope broke up and collapsed under the action of gravity. Later, ravines were formed on the slope. Caved slope clastics, accompanying lava flow, accumulated at the rims of the volcano cones. Although some accumulations may form very large cones, they are not volcanoes, but deposits of volcanic debris avalanches.