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琼北全新世火山区火山系统的划分与锥体结构参数研究 被引量:18
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作者 魏海泉 白志达 +5 位作者 胡久常 史兰斌 张秉良 徐德斌 孙谦 樊祺诚 《地震地质》 EI CSCD 北大核心 2003年第B12期21-32,共12页
根据琼北全新世火山区内火山作用产物的成因类型与喷发物理过程的野外考察结果 ,结合航片解译资料 ,确定了该区火山作用的发育特征、形成期次与规模 ,并以此作为进一步评价火山灾害的基础 ;根据锥体形成后物理降解作用与时间的关系 ,讨... 根据琼北全新世火山区内火山作用产物的成因类型与喷发物理过程的野外考察结果 ,结合航片解译资料 ,确定了该区火山作用的发育特征、形成期次与规模 ,并以此作为进一步评价火山灾害的基础 ;根据锥体形成后物理降解作用与时间的关系 ,讨论了琼北全新世火山区众多锥体结构参数之间的关系。研究结果为 :琼北全新世火山区分为 4个火山系统 ,即西北部的马鞍岭台地火山系统、东南部的雷虎岭盾片状火山系统、夹于二者之间的浩昌单成因火山系统和NW向裂隙式喷发系统。工作区内琼北新生代火山共计 5 9个 ,火山结构类型可分为火山锥、熔岩穹、熔岩湖与低平火山口等。在火山锥中 ,依据锥体组成与结构的差异又可进一步分为岩渣锥、溅落锥和混合锥等碎屑锥。琼北近代火山锥体高度多 <4 0m ,绝大多数锥体的底部直径 <5 0 0m。锥体底部直径和火口坑深度之间具有明显的正相关关系。 展开更多
关键词 全新世 火山系统 划分 锥体结构参数 琼北
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非火山系统地热流体移动的断块理论:在延伸地带的勘探模式
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作者 王湘 《新能源》 1994年第9期32-37,共6页
关键词 火山系统 地热流体移动 断块理论
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火山信息系统建立方法研究——以长白山火山区为例 被引量:3
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作者 张学霞 薄立群 常丽萍 《地质灾害与环境保护》 2000年第3期226-229,共4页
火山喷发是严重的地质灾害之一。全球各地都有火山分布 ,我国也有近千座火山。其中长白山火山、五大莲池火山和腾冲火山是我国最具潜在灾难性喷发危险的活火山。以长白山火山为例 ,阐述用建立火山信息系统的方法监测、预测、评估火山灾... 火山喷发是严重的地质灾害之一。全球各地都有火山分布 ,我国也有近千座火山。其中长白山火山、五大莲池火山和腾冲火山是我国最具潜在灾难性喷发危险的活火山。以长白山火山为例 ,阐述用建立火山信息系统的方法监测、预测、评估火山灾害 ,达到减灾。 展开更多
关键词 火山信息系统 突发性地热异常 本底数据库
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火山灾害信息系统建立方法研究
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作者 张学霞 薄立群 路兴昌 《中国减灾》 2001年第2期38-41,共4页
以长白山火山为例 ,阐述了用建立火山灾害信息系统的方法监测、预测、评估火山灾害 ,达到减灾、防灾的目的。
关键词 火山灾害信息系统 突发性地热异常 本底数据库 火山减灾 火山监测 火山预测
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裂谷火山型地热系统——奥卡瑞地热田基本特征 被引量:3
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作者 张志敏 魏小东 +3 位作者 杨惠童 胡圣标 王志伟 施亦做 《中外能源》 CAS 2018年第12期16-21,共6页
东非裂谷是世界著名的四大高温地热带之一,肯尼亚奥卡瑞地热田位于东非裂谷带中部,是典型的大陆裂谷火山型高温地热田.奥卡瑞地区断裂系统十分复杂,按走向可分为5组,其中以北西向为主要断裂,与裂谷走向一致.地热田整体面积约100km^2,目... 东非裂谷是世界著名的四大高温地热带之一,肯尼亚奥卡瑞地热田位于东非裂谷带中部,是典型的大陆裂谷火山型高温地热田.奥卡瑞地区断裂系统十分复杂,按走向可分为5组,其中以北西向为主要断裂,与裂谷走向一致.地热田整体面积约100km^2,目前投入生产的主要是东北区、东区和穹顶区,已落实热储面积约42km^2,主要有3个热源分别对东区、西区和穹顶区供热.奥卡瑞地热田是肯尼亚目前已知的热储温度最高的地热田,热储埋深为500~3000m,最高温度370℃,平均温度240℃.奥卡瑞高温地热系统的形成,与该地区晚第四纪强烈的火山活动有关,热田的盖层是最近一次火山活动的喷发物,以流纹岩为主,透水性差且裂缝不发育,使盖层成为良好的隔水层.热田热储主要为第四系火山岩,其中西区以凝灰岩为主,东区以粗面岩为主.地热水来源主要为大气降水,部分为渗入来源.综合分析认为,奥卡瑞地热田是一个由新近浅层侵入岩浆提供热源,由断裂、裂缝和有一定孔渗条件的火山岩构成热储,蚀变火山岩、流纹岩提供盖层,断裂作为热流体交换通道的火山型高温地热系统. 展开更多
关键词 奥卡瑞地热田 热储 热源 盖层 断裂 火山型地热系统
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岩浆补给作用对硅质火山岩浆系统演化的制约 被引量:6
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作者 颜丽丽 贺振宇 《地质学报》 EI CAS CSCD 北大核心 2022年第5期1697-1710,共14页
硅质火山喷发作为大陆地壳岩浆活动的重要表现,在研究大陆地壳形成与演化、探讨岩浆过程与动力学机制等方面具有重要的价值,其通常所表现的强烈爆炸式喷发,甚至可以导致全球性的环境和气候变迁。硅质岩浆系统在开放体系中不同来源岩浆... 硅质火山喷发作为大陆地壳岩浆活动的重要表现,在研究大陆地壳形成与演化、探讨岩浆过程与动力学机制等方面具有重要的价值,其通常所表现的强烈爆炸式喷发,甚至可以导致全球性的环境和气候变迁。硅质岩浆系统在开放体系中不同来源岩浆的贡献和相互作用是目前研究的热点问题。持续的岩浆补给可以延长岩浆存储的时间,促进岩浆房的对流、岩浆的分异演化以及晶体-熔体的分离和晶粥的再活化,同时也是触发火山喷发的重要机制之一。此外,岩浆补给以及硅质岩浆的晶体-熔体演化过程也是火山喷发产物多样性的原因,导致同一火山在其活动过程中喷发产物规律性的变化,如富晶体火山岩、贫晶体火山岩、火山岩成分分层、以及复活岩穹和中央侵入体等。因此,岩浆补给作用是制约硅质火山岩浆系统演化和火山岩成分多样性的重要因素,也是活动火山监测和灾害评估的重要依据。岩石学、岩石地球化学、矿物(长石、石英、石榴子石、锆石等)同位素及成分变化,以及模拟实验、地震层析成像等研究为揭示硅质岩浆系统中的岩浆补给作用和复杂岩浆过程提供了多种视角。 展开更多
关键词 岩浆补给 硅质火山岩浆系统 火山喷发 成分多样性 火山监测
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长白山地区火山机构信息系统的建立
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作者 赵文吉 晋佩东 李家存 《国土资源遥感》 CSCD 2000年第2期48-55,共8页
长白山火山机构信息系统是在系统设计与分析基础上建立的 ,共有 5个模块组成 :①长白山地区火山岩岩石化学数据库系统 ;②常量元素岩石化学分析系统 ;③微量元素岩石化学分析系统 ;④长白山火山构造信息系统 ;⑤长白山地区岩性岩相信息... 长白山火山机构信息系统是在系统设计与分析基础上建立的 ,共有 5个模块组成 :①长白山地区火山岩岩石化学数据库系统 ;②常量元素岩石化学分析系统 ;③微量元素岩石化学分析系统 ;④长白山火山构造信息系统 ;⑤长白山地区岩性岩相信息系统。数据库系统模块用VB语言开发完成 ;分析系统模块 ( 2个 )的建立是通过界面设计、结构分析、编程实现的 ;火山机构信息系统及岩性。 展开更多
关键词 火山信息系统 模块 数据库 长白山地区
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五大连池火山熔岩台地优势植物凋落物早期养分动态
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作者 谢宸 黄庆阳 +3 位作者 周庭宇 杨帆 谢立红 肖洋 《中南林业科技大学学报》 CAS CSCD 北大核心 2023年第5期120-129,共10页
【目的】为了探究火山生态系统凋落物养分释放(或流失)的动态变化规律。【方法】采用凋落物分解袋的方法,以五大连池火山熔岩台地中落叶松、白桦、山杨为代表的优势植物凋落物为研究对象,分析其分解速率及其养分释放动态差异。【结果】... 【目的】为了探究火山生态系统凋落物养分释放(或流失)的动态变化规律。【方法】采用凋落物分解袋的方法,以五大连池火山熔岩台地中落叶松、白桦、山杨为代表的优势植物凋落物为研究对象,分析其分解速率及其养分释放动态差异。【结果】6种凋落物叶片的质量残留率在不同时间、树种、来源间存在显著差异。根据Olson指数衰减模型,不同凋落物分解50%的时间是5.73~9.17 a,分解95%的时间是8.04~13.03 a,分解系数为0.545~0.994。分解速率表现为熔岩孤丘>熔岩台地且山杨>白桦>落叶松。从来源来看,凋落物分解过程中,其C含量、N含量以及P含量均表现为熔岩孤丘>熔岩台地,N∶P值均小于14。凋落物质量残留率与C元素呈极显著正相关,与N元素呈极显著正相关,与C∶N值呈显著负相关。C∶N值与N∶P值呈极显著负相关,与质量残留率呈显著负相关。【结论】相对于阔叶树种凋落物叶片,针叶树种凋落物叶片分解较慢。凋落物的C含量变化没有明显规律,P含量变化一致呈现先减后增的趋势,且P元素相比C元素、N元素更不易被溶出,分解过程中,凋落物样品受到N元素的影响最为显著,N含量越高且C∶N值越低,分解速率越快。 展开更多
关键词 火山生态系统 森林凋落物 分解速率 养分释放
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长白山天池火山监测工作进展 被引量:3
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作者 刘国明 于洪茌 谭雨文 《岩石学报》 SCIE EI CAS CSCD 北大核心 2006年第6期1491-1493,共3页
长白山天池火山是我国最具有潜在喷发危险的活火山。本文介绍了天池火山监测系统建设的基本情况,报道了近些年在火山地震监测、大地形变监测以及地球化学监测等方面的工作进展。
关键词 天池火山 火山监测系统 火山监测工作进展
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澜沧老厂多金属矿床叠加成矿系统稳定同位素对比研究 被引量:5
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作者 刀艳 杨帆 +1 位作者 李峰 赵晓勇 《岩石矿物学杂志》 CAS CSCD 北大核心 2014年第4期693-706,共14页
云南澜沧老厂多金属矿床是"三江"成矿带南段重要的多金属矿床之一,属于多种构造环境演变过程中形成的火山喷流沉积+隐伏斑岩热液成因为主的矿床,多因复成矿特征典型。本文在对不同成矿系统典型矿物/岩石开展S、Pb、H、O、Sm-N... 云南澜沧老厂多金属矿床是"三江"成矿带南段重要的多金属矿床之一,属于多种构造环境演变过程中形成的火山喷流沉积+隐伏斑岩热液成因为主的矿床,多因复成矿特征典型。本文在对不同成矿系统典型矿物/岩石开展S、Pb、H、O、Sm-Nd、Rb-Sr同位素分析研究的基础上,对比了不同成矿系统在矿床地球化学特征上的异同。研究表明,两个成矿系统的成矿物质来源既有继承性,又有新生性,多源特征明显。其中,火山喷流沉积成矿系统的S主要来源于火山热液,Pb主要来源于古陆壳基底和火山岩,成矿流体主要为海水与岩浆水的混合。斑岩型矿石矿物的S、Pb同位素组成也具壳幔混合源的特征,金属成矿物质来源主要与岩浆有关,成矿流体主要来源于岩浆水及大气降水,晚期成矿流体向大气降水漂移的特征相对明显。斑岩热液成矿系统中花岗斑岩的^(87)Sr/^(86)Sr比值介于地壳与地幔岩石平均值之间,Sm-Nd同位素数据接近EMⅡ地幔端员,指示岩浆源区处于壳-幔组分过渡区。 展开更多
关键词 火山喷流沉积成矿系统 斑岩热液成矿系统 S Pb H O Sr ND同位素 澜沧老厂 云南省
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山西省繁峙县茶坊金矿地质特征及成因探讨
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作者 黄红国 李振 +2 位作者 刘晓磊 张春岗 刘璐琦 《地质找矿论丛》 CAS 2024年第2期169-176,共8页
山西省茶坊金矿床产于新太古代奥长花岗岩(黑云斜长片麻岩)缓倾斜构造破碎带中。该矿区内断裂发育,其周边有燕山晚期石英斑岩、花岗闪长斑岩和辉石闪长岩呈脉状和小岩株状侵入。通过对茶坊金矿的矿床地质特征和矿床地球化学特征进行综... 山西省茶坊金矿床产于新太古代奥长花岗岩(黑云斜长片麻岩)缓倾斜构造破碎带中。该矿区内断裂发育,其周边有燕山晚期石英斑岩、花岗闪长斑岩和辉石闪长岩呈脉状和小岩株状侵入。通过对茶坊金矿的矿床地质特征和矿床地球化学特征进行综合研究,认为茶坊金矿属于与燕山晚期次火山岩浆活动有关的中低温热液型金矿。 展开更多
关键词 茶坊金矿 地质特征 矿床成因 火山斑岩成矿系统 中低温热液金矿 繁峙县 山西省
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探寻沸腾河
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作者 王安亦 《大自然探索》 2018年第3期24-32,共9页
传说在亚马孙雨林的深处,流淌着一条常年沸腾的河流。一位年轻的科学家深入雨林,探寻传说之河。16世纪,冒险家皮萨罗在获得了西班牙国王的准许后,带领第一波西班牙战士远征秘鲁。他们杀死了当时的印加国王,掠夺了大量的黄金和其他财宝,... 传说在亚马孙雨林的深处,流淌着一条常年沸腾的河流。一位年轻的科学家深入雨林,探寻传说之河。16世纪,冒险家皮萨罗在获得了西班牙国王的准许后,带领第一波西班牙战士远征秘鲁。他们杀死了当时的印加国王,掠夺了大量的黄金和其他财宝,并带回西班牙。轻而易举得来的大量财富吸引了更多西班牙人前往秘鲁。后续的西班牙人登陆这个南美王国,询问当地的印加人:哪里还有黄金?印加人告诉他们,在亚马孙丛林深处,坐落着黄金城市帕依提提。前往寻找黄金的西班牙大军一批批深入雨林。 展开更多
关键词 亚马孙雨林 西班牙人 火山 太平洋板块 火山系统 黄石国家公园 沉积岩 河水温度 印加人 火山喷发
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更新思路部署 促进找矿突破——以云南澜沧铅矿深部超大型斑岩钼(铜)矿发现为例 被引量:5
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作者 黎功举 张翼飞 +2 位作者 刘世维 张弢 陆继军 《云南地质》 2013年第3期251-258,263,共9页
依据澜沧铅矿2004~2010《全国危机矿山接替资源找矿勘查工作》项目所获,结合以往勘探采矿和科研成果,在原提出"上铅、下铜"金属分带规律的基础上,根据铜矿体下部有矽卡岩化和花岗斑岩脉以及上部铅矿石矿物中有辉钼矿、钨、... 依据澜沧铅矿2004~2010《全国危机矿山接替资源找矿勘查工作》项目所获,结合以往勘探采矿和科研成果,在原提出"上铅、下铜"金属分带规律的基础上,根据铜矿体下部有矽卡岩化和花岗斑岩脉以及上部铅矿石矿物中有辉钼矿、钨、锡矿化等异常现象,推断深部可能存在钼、锡、钨等的矿化类型(第三矿化带)。据此提出"层脉结合,远、近结合,拆墙扩储"的12字找矿新思路,调整工作部署、优选找矿靶区(位),终于在深部发现厚大斑岩型钼(铜)矿体,证实了预测。认为澜沧老厂矿床"三元矿化结构",实质上是一个完整的斑岩成矿系列,成矿时代为燕山晚期—喜马拉雅早期(始新统晚期为主),矿床成因为与隐伏岩体有关的中偏高温热液矿床。 展开更多
关键词 三元矿化结构 火山-斑岩成矿系统 新思路新部署 深部重大突破 云南澜沧铅矿
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Petrology,Geochemistry and Nd-Sr-Pb Isotopic Properties of Volcanic Rocks in Daheishan Island,Penglai,Shandong Province 被引量:3
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作者 傅永涛 李安春 《Marine Science Bulletin》 CAS 2003年第2期29-39,共11页
The major elements, trace elements. K-Ar age and Sr-Nd-Pb isotopie systems ofthe Cenozoic volcanic rocks in Daheishan Island and Cishan, Penglai, Shandong Province aremeasured. The volcanic rocks ( olivine-nephelinite... The major elements, trace elements. K-Ar age and Sr-Nd-Pb isotopie systems ofthe Cenozoic volcanic rocks in Daheishan Island and Cishan, Penglai, Shandong Province aremeasured. The volcanic rocks ( olivine-nephelinite and nephcline-basanite ) in Daheishan Islanderupted periodically in an interval of 0.32 Ma, from 8.72 Ma. 8.39 Ma. 8.08 Ma to 7.73 Ma. Thevolcanic rocks arc all rich in light REEs. They are similar to the OIB-type alkali basalt in thetrace elements normalized model by primordial mantle: rich in high field elements such as Nb and Ta,and imcompatible elements such as Cs. Rb, Ba, Th. U. The volcanic rocks show a depletion of K andRb elements. It is suggested by the trace elements that the olivine-nephelinite in Daheishan Islandis originated from deep resources under the continental mantle. ε Nd (0) values of the volcanicrocks in Daheishan Island and Cishan are 5.31~8.51 and 7.33 respectively, suggesting that thevolcanic rocks are from the depleted mantle resources, which have higher Sm/Nd ratios than the CHUR.^(143)Nd /^(144)Nd ratios ot Daheishan Island olivine-nephelinite and Cishan alkali basalts are0.512 910~0.513 074 and 0.513 014 respectively. The ^(87)Sr /^(86)Sr of Daheishan Island volcanicrocks are lower than that of Cishan, 0.703 427 ~0.703 482 and 0.703 895 respectively. The DaheishanIsland olivine-nephelinite has the Pb isotopie values as follows: ^(206)Pb/^(204)Pb= 18.028 9~17.972 8. ^(207)Pb / ^(204)Pb = 15.435 8 ~15.402 2 and ^(208)Pb /^(204)Pb = 38.087 6~37.997 5.lower than those of Cishan basanite. The Cishan basanite has ^(206)Pb/^(204)Pb= 18.240 1. ^(207)Pb/^(204)Pb= 15.564 5 and ^(208)Pb /^(204)Pb = 38.535. The authors suggest that theolivine-nephelinite in Daheishan Island is similar to the E-type MORB or Hawaii OIB, and the alkalibasalts in Cishan similar to the Kerguelen OIB. The dominant mantle components of DM+PREMA andperhaps DM ( Dupal type ) are the dominant mantle components for volcanic rocks in Daheishan Islandand Cishan. The PREMA component plays an important role. 展开更多
关键词 daheishan island penglai cenozoic volcanic rocks K-ar age DM PREMA
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Effects of atmospheric pressure fluctuations on hill-side coal fires and surface anomalies 被引量:5
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作者 Song Zeyang Zhu Hongqing +1 位作者 Xu Jiyuan Qin Xiaofeng 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2015年第6期1037-1044,共8页
This paper presents numerical studies on the effects of atmospheric pressure fluctuations on hill-side coal fires and their surface anomalies. Based on the single-particle reaction–diffusion model, a formula to estim... This paper presents numerical studies on the effects of atmospheric pressure fluctuations on hill-side coal fires and their surface anomalies. Based on the single-particle reaction–diffusion model, a formula to estimate oxygen consumption rate at high temperature controlled by oxygen transport is proposed.Daily fluctuant atmospheric pressure was imposed on boundaries, including the abandoned gallery and cracks. Simulated results show that the effects of atmospheric pressure fluctuations on coal fires and surface anomalies depend on two factors: the fluctuant amplitude and the pressure difference between inlet(s) and outlet(s) of the air ventilation system. If the pressure difference is close to the fluctuant amplitude, atmospheric pressure fluctuations greatly enhance gas flow motion and temperatures of the combustion zone and outtake(s). If the pressure difference is much larger than the fluctuant amplitude, atmospheric pressure fluctuations exert no impact on underground coal fires and surface anomalies. 展开更多
关键词 Coal firesOxygen consumpdon rateAir leakageVentilation
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Regional metallogenic structure based on aeromagnetic data in northern Chile 被引量:3
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作者 Zhu Xiao-San Lu Min-Jie 《Applied Geophysics》 SCIE CSCD 2016年第4期721-735,740,共16页
Chile is a very important country that forms part of the Andean metallogenic belts. The Atacama and Domeyko fault systems in northern Chile control the tectonic- magmatic activities that migrate eastward and the types... Chile is a very important country that forms part of the Andean metallogenic belts. The Atacama and Domeyko fault systems in northern Chile control the tectonic- magmatic activities that migrate eastward and the types of mineral resources. In this paper, we processed and interpreted aeromagnetic data from northern Chile using reduction to pole, upward field continuation, the second derivative calculation in the vertical direction, inclination angle calculation, and analytical signal amplitude analysis. We revealed the locations and planar distribution characteristics of the regional deep faults along the NNE and NS directions. Furthermore, we observed that the major reasons for the formation of the tectonic-magmatic rocks belts were the nearly parallel deep faults distributed from west to east and multiple magmatic activities along these faults. We ascertained the locations of volcanic mechanisms and the relationships between them using these regional deep faults. We deduced the spatial distributions of the basic-intermediate, basic, and acidic igneous rocks, intrusive rocks, and sedimentary sequences. We showed the linear positive magnetic anomalies and magnetic anomaly gradient zones by slowly varying the background, negative magnetic anomaly field, which indicated the presence of strong magmatic activities in these regional deep faults; it also revealed the favorable areas of copper and polymetallic mineralization. This study provides some basic information for further research on the geology, structural characteristics, and mineral resource prospecting in northern Chile. 展开更多
关键词 Andean metallogenic belt aeromagnetic anomaly Atacama fault system Domevko fault system structural interpretation volcanic mechanism
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The first meteorological observations at a tropical high elevation site:Antisana,1846 被引量:1
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作者 Aria Ma M.FARRONA Fernando DOMINGUEZ-CASTRO +1 位作者 Ma Cruz GALLEGO Jose M.VAQUERO 《Journal of Mountain Science》 SCIE CSCD 2016年第6期1047-1055,共9页
Antisana is a stratovolcano with an associated glacier located in the Ecuadorian Andes. Dr Aguirre made meteorological readings every day, at every hour from sunrise to sunset, from December 1845 to December 1846, at ... Antisana is a stratovolcano with an associated glacier located in the Ecuadorian Andes. Dr Aguirre made meteorological readings every day, at every hour from sunrise to sunset, from December 1845 to December 1846, at Antisana using a meteorological station at 4060 mamsl (meters above mean sea level). Unfortunately, only the monthly average data have been preserved. These meteorological data are here studied and compared with the closest modern stations for monthly values of temperature, rainfall, and pressure. According to these comparisons, the year 1846 was rainy and cold in comparison with the current climate. Moreover, these observations have been useful to help resolve a debate about a possible E1Nifio event in 1846 with the high precipitation in Antisana and Quito in 1846 discarding the occurrence of an E1 Nifio event. The probable occurrence of a La Nifia event is discussed. These data are the earliest known systematic instrumental meteorological observations taken at above 4000 mamsl. 展开更多
关键词 Early instrumental records GLACIER Pastclimate conditions
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Numerical Simulation and Probabilistic Hazard Assessment of Tephra Fallout at Jinlongdingzi Volcano,Longgang Volcanic Field in Jilin Province
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作者 Yu Hongmei Xu Jiandong +2 位作者 Wu Jianping Luan Peng Zhao Bo 《Earthquake Research in China》 2013年第3期391-400,共10页
Tephra fallout is an important type of hazard caused by explosive volcanic eruption, and numerical simulation has become a fast and effective approach to assess the dispersion and deposition of tephra fallout. Accordi... Tephra fallout is an important type of hazard caused by explosive volcanic eruption, and numerical simulation has become a fast and effective approach to assess the dispersion and deposition of tephra fallout. According to the improved 2D diffusion model of Suzuki ( 1983), we edited a tephra diffusion program that can run in the Windows system. Based on previous data, we simulated the diffusion scope of the Jinlongdingzi volcanic eruption, which is the latest eruption in the Longgang volcanic cluster. The simulated results are in good agreement with the results from measurement in situ, indicating that the model is reliable and the parameters used in the model are suitable. By using wind profiles of ten years, 7, 021 simulations under different wind profiles were carried out, and then probabilistic hazard maps of tephra fallout were constructed for tephra thickness thresholds, lcm and 0.5cm. This study can provide an important scientific basis for volcanic hazard analysis, risk mitigation plans and countermeasures in the Longgang volcanic area. 展开更多
关键词 Tephra fallout Numerical simulation Hazard probability maps Jinlongdingzi volcano Longgang volcanic cluster
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Initiation and recession of the fluvial knickpoints:A case study from the Yalu River-Wangtian'e volcanic region,northeastern China 被引量:13
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作者 ZHANG HuiPing ZHANG PeiZhen FAN QiCheng 《Science China Earth Sciences》 SCIE EI CAS 2011年第11期1746-1753,共8页
Initiation and recession of the knickpoints are significant boundary condition for processes of fluvial system. The distribution and recession rates of knickpoints contain information that provides a fundamental under... Initiation and recession of the knickpoints are significant boundary condition for processes of fluvial system. The distribution and recession rates of knickpoints contain information that provides a fundamental understanding of geomorphic processes. In the Yalu River-Wangtian'e volcanic region of northeastern China, broadly distributed fiat lava terrain provides an ideal site to study the recession of fluvial knickpoints because knickpoints and waterfalls are well preserved here. Here we describe the distribution of knickpoints in the Yalu River-Wangtian'e volcanic region by combining DEM analysis and numerical modeling Furthermore, we present a knickpoint celerity model, derived from stream-power incision model, to relate knickpoint recession rate to drainage area. We calibrate important empirical coefficients with our knickpoint celerity model; the best fit erosion coefficient (K) is 1.32×10^-8, and the best fit drainage area exponent (m) is 0.69. Error analysis indicates a close correspondence between synthetic and real knickpoints. Finally, we show that knickpoint recession rates in the Yalu River-Wangtian'e volcanic region are -1-10 mm/a during the early stages of transient incision, and that the present rates are -1-6 mm/a. Our recession rate results are in good agreement with previous findings from the Aso Volcano and volcanoes near Boso Peninsula (Japan), which have a similar geologic history to the Yalu River-Wangtian'e volcanic region. Our present effort provides new insight into landscape evolution in the Yalu River-Wangtian'e volcanic region in northeastern China. 展开更多
关键词 Yalu River-Wangtian'e volcanic region KNICKPOINT knickpoint celerity model landscape evolution
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Global wood anatomical perspective on the onset of the Late Antique Little Ice Age (LALIA) in the mid-6th century CE 被引量:1
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作者 Ulf Büntgen Alan Crivellaro +36 位作者 Dominique Arseneault Mike Baillie David Barclay Mauro Bernabei Jarno Bontadi Gretel Boswijk David Brown Duncan A.Christie Olga V.Churakova Edward R.Cook Rosanne D’Arrigo Nicole Davi Jan Esper Patrick Fonti Ciara Greaves Rashit M.Hantemirov Malcolm K.Hughes Alexander V.Kirdyanov Paul J.Krusic Carlos Le Quesne Fredrik C.Ljungqvist Michael Mc.Cormick Vladimir S.Myglan Kurt Nicolussi Clive Oppenheimer Jonathan Palmer Chun Qin Frederick Reinig Matthew Salzer Markus Stoffel Max Torbenson Mirek Trnka Ricardo Villalba Nick Wiesenberg Greg Wiles Bao Yang Alma Piermattei 《Science Bulletin》 SCIE EI CAS CSCD 2022年第22期2336-2344,共9页
Linked to major volcanic eruptions around 536 and 540 CE, the onset of the Late Antique Little Ice Age has been described as the coldest period of the past two millennia. The exact timing and spatial extent of this ex... Linked to major volcanic eruptions around 536 and 540 CE, the onset of the Late Antique Little Ice Age has been described as the coldest period of the past two millennia. The exact timing and spatial extent of this exceptional cold phase are, however, still under debate because of the limited resolution and geographical distribution of the available proxy archives. Here, we use 106 wood anatomical thin sections from 23forest sites and 20 tree species in both hemispheres to search for cell-level fingerprints of ephemeral summer cooling between 530 and 550 CE. After cross-dating and double-staining, we identified 89Blue Rings(lack of cell wall lignification), nine Frost Rings(cell deformation and collapse), and 93Light Rings(reduced cell wall thickening) in the Northern Hemisphere. Our network reveals evidence for the strongest temperature depression between mid-July and early-August 536 CE across North America and Eurasia, whereas more localised cold spells occurred in the summers of 532, 540–43, and548 CE. The lack of anatomical signatures in the austral trees suggests limited incursion of stratospheric volcanic aerosol into the Southern Hemisphere extra-tropics, that any forcing was mitigated by atmosphere-ocean dynamical responses and/or concentrated outside the growing season, or a combination of factors. Our findings demonstrate the advantage of wood anatomical investigations over traditional dendrochronological measurements, provide a benchmark for Earth system models, support cross-disciplinary studies into the entanglements of climate and history, and question the relevance of global climate averages. 展开更多
关键词 Blue Rings Climate extremes Dendrochronology Late Antiquity Tree rings Volcanic eruptions
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