Gas emission from active fault zones around the Jilantai faulted depression basin and its implications for fault activities
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摘要: 为了研究吉兰泰断陷盆地周缘断裂带气体排放及其对断层活动性的指示意义,在盆地周缘4条活动断裂上布设了5条土壤气测量剖面和1条电磁测量剖面,观测了土壤气中Rn,Hg和CO2的浓度、释放通量和地电阻率,对各测量剖面进行了土壤化学组分分析,计算得到了断层活动性相对指数KQ。研究结果显示:土壤气体CO2和Rn受渗透性较低的粉砂土阻挡,主要沿结构破碎的断层上盘逃逸,并形成浓度高峰;吉兰泰盆地南缘土壤气Rn,Hg和CO2的浓度和释放通量最高,可能与盆地西南缘花岗岩中U和Ra的运移以及盆地南缘碳酸盐岩的分解有一定的关系。各测量剖面的断层活动性相对指数KQ值的变化特征表明,正断层和逆断层的KQ值大于走滑断层,且巴彦乌拉山山前断裂上的KQ值最高,揭示其活动性最强,有可能是地震发生的潜在危险区。Abstract: Soil gases from fault zones are good indicators of tectonic and seismic activities, to which many seismologists and geochemists have been paid much attention. Five measuring sections for soil gas and one for earth resistivity were designed on the four active faults around the Jilantai basin, northwestern China. The data of earth resistivity, concentration and flux of soil gases Rn, Hg and CO2 were attained, and the chemical compositions of soil were analyzed in all sections and the relative index KQ of fault activity was calculated. All the results showed that soil gases CO2 and Rn were blocked by sandy soil layers with low permeability and escaped along the hanging wall of the faults with broken structures, easily forming concentration peaks. High concentrations and fluxes of Rn, Hg and CO2 were distributed in the southern margin of the Jilantai basin, which might be related to the migration of U and Ra in granites in southwestern margin of the basin and the decomposition of local carbonate rocks in south margin of the basin. The variation characteristics of relative index KQ of fault activity in each section indicated normal and reverse faults with higher KQ values than strike-slip faults. The maximum KQ value was observed in the piedmont fault of Bayanwula mountains, probably indicating that this fault is of the strongest activity and is also a potential area of high seismic hazards.
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Keywords:
- Jilantai faulted depression basin /
- fault zone /
- soil gases /
- geochemistry /
- flux /
- fault activity
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引言
地震波的震相在地震学发展及地球结构研究中起着重要的作用。随着数值计算方法的发展和观测技术水平的提高,逐渐可以利用地震波形中尽可能多的信号来研究地球结构(崇加军,2013)。地震波是源自震源和震中区的弹性波,震相是地震波显示在地震记录图上的信号(赵荣国,1999)。震相分析对深入研究地球的内部构造和探查地震活动规律具有极为重要的意义,地震震相识别也是省级地震分析和编目工作的一项常规工作。地震震相识别中,人工识别的成分占较大比例,而且由于震源机制和传播介质的复杂性,同一种震相在不同地震中的形态均不相同(杨配新等,2004),因此常见的震相Pn,Pg,Sn,Sg较易识别,但非常见的震相识别难度较大。而康拉德面是不连续面,地震波速度在深度变化的过程中均匀变化,因此Pb震相不易被发现,难以得到地震分析人员的关注。
1923年,奥地利研究人员康拉德发现,大陆地壳内部还存在这样一个界面(Conrad,1925):该界面以上,岩石密度较低,为硅铝层,由中酸性岩石组成;该界面以下,岩石密度较高,为硅镁层(铁镁层),由基性岩石组成。该界面被称为康拉德(Conrad)不连续面,简称康氏面或康拉德面(刘瑞丰等,2014)。此后许多地震学研究人员在大陆地壳内不同区域和不同尺度上也探测到了该界面(Berry,Fuchs,1973;胡德昭等,1989;郭杰等,2013),并对其进行了相关研究。胡德昭等(1989)在中国东南部地壳内探查到康拉德面;1970—1994年期间,苏联的超深钻井项目研究显示康拉德界面上的地震波速度跃变非常大(Richard,1989;Pavlenkova,1993)。但康拉德界面是否普遍存在仍有争议。相关研究认为,康拉德界面与研究区的地壳结构及其演化历史密切相关,在海洋地壳内或者有时在构造活动比较强烈的大陆地壳内,康拉德界面可能是缺失的(Litak,Brown,1989;Richard,1989;Pavlenkova,1993)。近期研究已在有些地质构造活动比较强烈的区域记录到的地震波形中发现有来自康拉德界面的强振幅震相(刘赛君等,2011;郭杰等,2013),且焦煜媛等(2017)已在青藏高原东北缘找到康拉德面存在的直接地震学证据。郭杰等(2013)在位于豫北东的濮阳市地震台的观测中发现了康拉德界面的反射波震相。
关于海南地区Pb震相的研究,也有一些相关的研究成果。范玉兰等(1990)在研究华南地区近震走时表时,描述到海口台、文昌台、定安台、那大台、琼中台等海南省台站在震中距大于151 km时,可记录到清晰的Pb震相;刘赛君等(2011)在海南岛西南海域地壳剖面海陆联合探测研究中提到Pb震相在50—130 km偏移距范围内可被追踪到。
这样看来,有些地区不仅有康拉德面存在的证据,而且前人已记录到海南地区存在Pb震相,因此有必要进一步研究海南地区的Pb震相,故本文一方面以云南省地震台网和广东省地震台网记录到的Pb震相为基础,采用折合走时分析,将其结果作为参考数据;另一方面重点分析海南省地震台网记录到的地震事件,并使用PTD方法(朱元清等,1990)重新定位地震事件的震源深度,以Pb震相理论到时结合实际波形,标注Pb震相,进而拟合标注的震相速度(林建民等,2008)。 此外,综合前人的研究成果(李志雄等,2008;刘赛君等,2011;黄海波等,2012;Kumar et al,2016 )来分析Pb震相的物理特性,最后确定Pb震相。通过识别Pb震相,探查海南地区康拉德面的深度变化,对该地区一维速度模型的建立、地震定位精度的提高以及地震活动、地震定位深度等研究均具有重要意义。
1. 资料和方法
1.1 资料选取
本文研究区域为海南地区(106°E—114°E,17°N—23°N),选取2009年1月1日至2016年8月25日期间发生在研究区域内的地震,并按照以下标准严格筛选地震事件:① 至少被10个台站记录到;② 地震震级ML≥2.0;③ 地震事件含有Pn震相。最终统计筛选得到Pg震相1 549个,Pn震相588个,无Pb震相。由于研究区域的数据中不包含Pb震相,故以2009年至2016年云南省、广东省地震台网的数据为参考资料,按照上述标准,最终云南地区的震相筛选结果为:Pg震相49 521个,Pb震相3 406个,Pn震相10 781个;广东地区的震相筛选结果为:Pg震相5 038个,Pb震相23个,Pn震相2 240个。
1.2 方法
1.2.1 理论走时
由于近震波的传播路程短,受地球曲率影响小,因此在研究近震问题时,通常将地球表面及各层界面看作水平界面(刘瑞丰等,2014)。Pb震相是在康拉德面上的纵波性首波,其传播路径如图1所示。由该图所示的Pb震相走时路径,依据斯奈尔(Snell)定理和地震波走时方程,可求得Pb的理论走时为
${t_{{\rm{Pb}}}} {\text{=}} \frac{\varDelta }{{{v_2}}} {\text{+}} \left( {2{H_1} - h} \right)\frac{{\cos i}}{{{v_1}}},$
(1) 式中,tPb为Pb震相走时,Δ为震中距,H1为康拉德面深度,h为震源深度,v1为一维速度模型中第一层的Pg波平均速度,v2为第二层的Pb波速度,i为Pb波入射角。
1.2.2 折合走时
折合走时与介质厚度(康拉德界面或者莫霍面深度)、震源深度和波速相关(王莉婵等,2016),在同一震源深度的情况下,理论折合走时应为常数值b,震相走时可理解为横向走时和折合走时,因此将式(1)变换为
${t_{\rm redu}} {\text{=}} t - \frac{\varDelta }{v},$
(2) 式中tredu为折合走时,t为理论震相或观测震相走时,v为波速。
1.2.3 PTD定位方法
PTD定位方法是采用初至波为Pg直达波的台站到时和初至波为Pn首波的台站到时,经转换后的到时差来确定地震的震源深度(朱元清等,1990)。测定震源深度的分辨率为深度每改变5 km,到时差改变0.7 s,换句话说,初动到时测量误差每增加0.1 s,深度误差则增加0.7 km (朱元清等,1997)。
本文可辨别出Pb震相的地震共计52次,由于原震源深度定位偏浅,8 km左右的深度占大部分,因此重新测定震源深度,便于下一步震相理论到时的计算。图2给出了使用PTD定位前后的震源深度比较,可见使用PTD方法测定深度可减小初动到时测量误差引起的深度误差,在深度测定方面有较大的优势。
1.2.4 模型选取
数据处理涉及理论值计算,速度模型是必不可少的部分,虽然目前大多采用IASP91模型,但由于本文涉及云南省(2015模型)、广东省(华南模型)和海南省(2015模型)的数据(朱元清等,2017),考虑到一维速度模型与到时数据之间的一致性(Wang,2014),本文采用各省的一维速度模型作为各自省份参与计算的理论到时,各省的速度模型列于表1。
表 1 云南、广东和海南各省份的地壳速度模型表Table 1. The crustal velocity model of Yunnan,Guangdong and Hainan Provinces省份 v1/(km·s−1) v2/(km·s−1) v3/(km·s−1) H1/km H/km 云南 6.01 6.60 7.89 20 41 广东 6.00 6.87 7.96 22 33 海南 6.00 6.84 7.97 21 30 注:v1和v2分别表示第一、二层的平均速度,v3表示莫霍面的平均速度,H1表示第一层的平均厚度,H表示莫霍面的平均厚度。 2. Pb震相识别
2.1 云南、广东Pb震相分析
采用折合走时分析云南、广东两省份的数据,结果显示:云南省的Pb震相数据基本处于理论震相范围内,标注的Pb震相接近该地区的康拉德面;广东省的Pb震相数据几乎全在理论震相范围内,标注的Pb震相在康拉德面上。这表明结果良好,与预期结果相符,故可用此方法分析海南的Pb震相数据。
2.2 海南Pb震相识别
震相识别的步骤为:① 对资料进行预处理,筛选出含有Pn震相的地震事件,共计281次;② 对281次地震事件使用PTD法重新定位其震源深度;③ 计算震相理论到时,结合人工分析识别出Pb震相;④ 对识别出的Pb震相进行速度拟合;⑤ 分析和佐证识别的Pb震相结果。
以近几年海南地区发生的影响较大的两次地震为例:事件1为2012年11月5日19时51分海南万宁ML4.1地震,那大台记录的波形见图3左;事件2为2014年7月28日10时10分海南儋州ML3.3地震,万宁台记录的波形见图3右。
那大台的震中距为169 km,PTD重新定位深度为10 km,计算其Pg,Pb,Pn的理论走时分别为28.21,27.26,26.06 s,在实际波形识别的相应结果分别为28.54,27.33,26.33 s。依据波形特性、振幅、周期等因素,Pb震相处于Pn震相与Pg震相之间,其振幅稍大于Pn,但小于Pg振幅,符合绕射波的动力学特征。实际人工识别Pb震相走时t2与理论走时t1相差无几,人工识别的Pb震相标注见图3。
以同样的方法,对万宁台记录到的事件2进行PTD定位计算,结果显示重定位深度为13 km,Pg,Pb,Pn震相的理论走时分别为21.60,21.18,20.71 s,实际波形识别的相应结果分别为21.61,21.22,21.04 s。
依据上述震相识别步骤,在281次地震事件中,从52次地震事件能识别出Pb震相57个,含有Pb震相的地震分布如图4所示。通过分析识别结果可知,能记录到Pb震相的台站共计16个,占全部台站个数(24)的67%,且分布均匀,统计台站记录到Pb震相的震中距处于66.75—234 km范围内,这与海南岛西南海域地壳剖面海陆联合探测研究中追踪到的Pb震相的震中距结果(刘赛君等,2011)基本相近。
采用速度线性拟合(图5)和折合走时(图6)两种方式分析Pb震相的速度,以佐证识别的震相是否与其物理意义相符,图6中折合走时理论值是基于海南模型计算而得。从图5可知,Pb速度为6.47 km/s,在对数据进行折合走时分析的过程中,扰动第二层的速度为6.65 km/s时,能达到图6的效果,这说明实际震相处于理论值范围内。海南地区在区域构造的伸展作用下,其地壳厚度相对正常大陆型地壳较薄,具有西南厚、东北薄的特点(黄海波等,2012),康拉德面作为上下地壳的分界面,穿过界面的波速由6.0 km/s激增至6.4 km/s (刘赛君等,2011)。
使用折合走时分析全部Pb震相,结果表明,实际震相基本处于理论震相范围内,尽管有些震相的实际走时与理论走时有偏差,这可能与一维模型单一、不能有效地反映局部地壳内部结构的复杂性和不均匀性有关。综合上述速度拟合分析,识别的Pb震相符合海南地区地震波在康拉德面滑行的物理意义。
3. 海南地区康拉德面
康拉德面是地球内部的次级不连续面,其深度介于10—40 km之间,在陆壳内的平均深度约为20 km (殷伟伟等,2017)。考虑到海南地区的地壳较薄,选取10—30 km作为反演海南地区的康拉德面深度Hi。当Hi以一定步长从10 km依次增加至30 km时,将记录到Pb震相的台站震中距、地震震源深度代入式(1),可得到理论走时t1,t1与实测走时t2之差的绝对值的最小值,即Pb震相的走时残差,为Y=min|t1−t2|,则57次地震的平均走时残差Si为
${S_i} = \frac{1}{{57}}\sum\limits_{i = 1}^{57} {{Y_i}} .$
(3) 为了较好地反映康拉德面的深度和速度情况,通过计算康拉德面的速度和深度变化,可得到平均走时残差Si随深度和速度变化的分布。取Pb波速度为6.40—6.84 km/s,以0.1 km/s的步长计算所有走时残差;深度范围取10—30 km,以1 km的步长计算。计算结果表明速度为6.60—6.80 km/s、深度为19—22 km时残差最小。基于该结果,按上述方法重复,进一步细算速度和深度变化,速度以0.02 km/s为步长,深度以0.5 km为步长,计算结果如图7所示。结果表明,海南地区的Pb波速度为6.60—6.72 km/s、深度为19—21.5 km较为合理。
4. 讨论与结论
本文利用海南省记录到的地震事件,识别了Pb震相并反演得到海南地区的康拉德面深度。结果显示,海南地区的Pb波速度介于6.60—6.72 km/s之间、康拉德面在19—21.5 km左右较合理。海南地区Pb波速度与前人的研究结果(范玉兰等,1990;刘赛君等,2011)基本吻合,首次在海南地区得出康拉德面的合理范围。由于初至Pb震相难识别,缺乏实际震相支持,今后会持续关注这方面的震相数据。
本文结果能对地震分析识别Pb震相起到辅助作用,可为建立海南地区的地壳速度模型提供参考资料。但是,由于本文研究的大部分震源位于上地壳,研究结果具有一定的局限性,震源位于下地壳时震相的识别有待进一步研究。
上海市地震局的朱元清研究员和海南省地震局的李志雄研究员、张慧高工对本研究给予了指导,江苏省地震局廖发军高工分别为本文提供了PTD软件,审稿专家提出了修改意见,作者在此一并表示衷心的感谢!
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图 1 研究区构造简图和1970年7月19日至2018年6月10日的地震分布(a)以及垂向剖面AA' 简图(b)
F1:巴彦乌拉山山前断裂;F2:狼山山前断裂;F3:桌子山西缘断裂;F4:正谊关断裂
Figure 1. The tectonic settings and distribution of earthquakes from 19 July 1970 to 10 June 2018 in the studied area (a) and the vertical profile AA' (b)
F1:Bayanwula mountain Piedmont fault;F2:Langshan mountain Piedmont fault;F3:Zhuozi mountain Western margin fault of;F4:Zhengyiguan fault
图 14 中国不同地区土壤气浓度和释放通量对比图
数据引自Li等(2013),Zhou等(2016)和杨江(2018)
Figure 14. Contrast map of concentrations and fluxes of soil gases from different places in China
Data is after Li et al (2013),Zhou et al (2016) and Yang (2018)
表 1 土壤气Rn,Hg和CO2测量剖面基本信息
Table 1 Basic information about the measurement sections for soil gases Rn,Hg and CO2
剖面 剖面编号 断裂 断裂编号 断裂性质 北纬/° 东经/° 巴彦乌拉 BYWL 巴彦乌拉山山前断裂 F1 正断层 39.5 105.2 乌兰巴兴 WLBX 狼山山前断裂 F2 正断层 40.4 106.2 那仁乌布尔嘎查 NRWBEGC 狼山山前断裂 F2 正断层 40.9 106.6 大路盖 DLG 桌子山西缘断裂 F3 逆断层 40.0 106.8 正义关 ZYG 正谊关断裂 F4 左旋走滑 39.3 106.7 注:土壤气剖面的经纬度是测线中央(剖面与断层相交处)的经纬度。 表 2 土壤气Rn,Hg和CO2浓度的测量结果
Table 2 Measurement results of the concentrations of soil gases Rn,Hg and CO2
测线编号 测项 Qmean σ Qmean+σ/2 Qmean-σ/2 Qmax Qmin KQ BYWL-1 CO2 0.08% 0.03 0.09% 0.07% 0.14% 0.06% 2.33 BYWL-2 0.11% 0.04 0.13% 0.09% 0.18% 0.04% 4.50 DLG-1 0.10% 0.02 0.11% 0.08% 0.14% 0.06% 2.33 DLG-2 0.10% 0.04 0.12% 0.08% 0.23% 0.07% 3.29 NRWBEGC-1 0.22% 0.06 0.25% 0.19% 0.38% 0.14% 2.71 WLBX-1 0.14% 0.05 0.16% 0.11% 0.28% 0.11% 2.55 WLBX-2 0.12% 0.03 0.13% 0.10% 0.16% 0.07% 2.29 ZYG-1 0.23% 0.06 0.26% 0.20% 0.32% 0.16% 2.00 ZYG-2 0.22% 0.06 0.25% 0.19% 0.36% 0.15% 2.48 BYWL-1 Hg 13 6 16 10 30 6 5.00 BYWL-2 10 3 11 8 15 6 2.50 DLG-1 12 4 14 10 24 8 3.00 DLG-2 12 3 13 11 19 8 2.38 NRWBEGC-1 10 4 12 8 18 4 4.50 WLBX-1 10 3 11 8 16 8 2.13 WLBX-2 10 3 11 9 15 7 2.14 ZYG-1 9 2 10 8 12 7 1.85 ZYG-2 11 3 12 9 15 7 2.14 BYWL-1 Rn 9.784 6.768 13.168 6.400 27.827 4.403 6.32 BYWL-2 16.966 18.015 25.973 7.958 60.091 3.974 15.12 DLG-1 2.486 1.099 3.036 1.937 4.975 0.739 6.73 DLG-2 2.417 0.947 2.891 1.944 4.381 1.008 4.35 NRWBEGC-1 9.394 2.899 10.843 7.944 13.376 5.818 2.30 WLBX-1 2.215 0.417 2.423 2.007 2.842 1.643 1.73 WLBX-2 2.018 0.674 2.355 1.681 3.764 0.739 5.09 ZYG-1 7.058 2.409 8.263 5.854 10.420 3.833 2.72 ZYG-2 7.289 1.970 8.274 6.304 10.822 4.706 2.30 注:Rn和Hg的浓度Q的单位分别为kBq·m−3和ng·m−3;Qmean,σ,Qmean+σ/2,Qmean-σ/2,Qmax和Qmin分别为每条测线上浓度的平均值、标准偏差、异常上限、异常下限、最大值和最小值;KQ为断层活动性指数。 表 3 土壤气剖面的平均浓度Q和释放通量F
Table 3 The average values of concentration Q and flux F at each soil gas section
剖面 FCO2/(g·m−2·d−1) FRn/(mBq·m−2·s−1) FHg/(ng·m−2·h−1) QCO2 QRn/(kBq·m−3) QHg/(ng·m−3) BYWL 11.76 39.07 7.46 0.09% 13.375 11 ZYG 15.17 12.71 0 0.23% 7.174 10 DLG 10.52 22.82 0 0.10% 2.452 12 NRWBEGC 9.38 17.25 3.69 0.22% 9.394 10 WLBX 6.54 5.17 0.62 0.13% 2.117 10 平均值 10.67 19.40 2.35 0.15% 6.902 11 表 4 土样化学组分分析测试结果
Table 4 The test results of chemical composition analysis of soil samples
剖面 CU/(Bq·kg−1) CTh/(Bq·kg−1) CRa/(Bq·kg−1) CK/(Bq·kg−1) TC含量 CHg/(ng·g−1) BYWL 39.8 46.2 28.7 616 0.972% 1.54 DLG 24.2 36.8 23.7 546 0.762% 13.30 NRWBEGC 40.2 52.7 30.6 944 0.163% 5.67 WLBX 17.6 17.6 13.0 553 0.577% 5.85 ZYG 8.1 44.5 27.2 559 2.420% 28.90 注:所采土样于2017年8月由核工业地质研究所进行检测;C为质量活度。 -
曹刚. 2001. 内蒙古地震研究[M]. 北京: 地震出版社: 1−174. Cao G. 2001. Earthquake Research in Inner Mongolia[M]. Beijing: Seismological Press: 1−174 (in Chinese).
程鉴基. 1997. 汞断层气异常与活断层关系浅析[J]. 地壳形变与地震,17(2):97–100. Cheng J J. 1997. Elementary analysis of relationship between mercury anomaly of fault product gas and active fault[J]. Crustal Deformation and Earthquake,17(2):97–100 (in Chinese).
杜建国, 李营, 崔月菊, 孙凤霞. 2018. 地震流体地球化学[M]. 北京: 地震出版社: 1−272. Du J G, Li Y, Cui Y J, Sun F X. 2018. Seismic Fluid Geochemistry[M]. Beijing: Seismological Press: 1−272 (in Chinese).
付碧宏,王萍,孔屏,郑国东,王刚,时丕龙. 2008. 四川汶川5·12大地震同震滑动断层泥的发现及构造意义[J]. 岩石学报,24(10):2237–2243. Fu B H,Wang P,Kong P,Zheng G D,Wang G,Shi P L. 2008. Preliminary study of coseismic fault gouge occurred in the slip zone of the Wenchuan MS8.0 earthquake and its tectonic implication[J]. Acta Petrologica Sinica,24(10):2237–2243 (in Chinese).
高立新,孙加林,张晖. 2010. 中强地震平静是汶川8.0级地震前最显著的地震活动异常[J]. 地震,30(1):90–97. doi: 10.3969/j.issn.0253-4967.2010.01.009 Gao L X,Sun J L,Zhang H. 2010. Moderate-to-strong earthquake quiescence is the most significant seismic anomaly before the Wenchuan 8.0 earthquake[J]. Earthquake,30(1):90–97 (in Chinese).
高立新,戴勇,贾宁. 2012. 鄂尔多斯块体周缘地震活动特征分析[J]. 防灾科技学院学报,14(4):70–79. doi: 10.3969/j.issn.1673-8047.2012.04.014 Gao L X,Dai Y,Jia N. 2012. Study on seismic activity characteristics in Ordos block and seismic risk analysis of northern edge[J]. Journal of Institute of Disaster Prevention,14(4):70–79 (in Chinese).
高立新,韩晓明,戴勇,李娟,杨红缨. 2017. 鄂尔多斯地块的运动特性与现今地震活动性[J]. 大地测量与地球动力学,37(4):349–354. Gao L X,Han X M,Dai Y,Li J,Yang H Y. 2017. Movement characteristics and the present seismic behavior of the Ordos block[J]. Journal of Geodesy and Geodynamics,37(4):349–354 (in Chinese).
郭正府,郑国东,孙玉涛,张茂亮,张丽红,成智慧. 2017. 中国大陆地质源温室气体释放[J]. 矿物岩石地球化学通报,36(2):204–212. doi: 10.3969/j.issn.1007-2802.2017.02.003 Guo Z F,Zheng G D,Sun Y T,Zhang M L,Zhang L H,Cheng Z H. 2017. Greenhouse gases emitted from geological sources in China[J]. Bulletin of Mineralogy,Petrology and Geochemistry,36(2):204–212 (in Chinese).
韩清. 1982. 乌兰布和沙漠的土壤地球化学特征[J]. 中国沙漠,2(3):24–31. Han Q. 1982. The geochemical characteristics of the soils in the Ulanbuh desert[J]. Journal of Desert Research,2(3):24–31 (in Chinese).
何继善. 1990. 可控源音频大地电磁法[M]. 长沙: 中南工业大学出版社: 1−169. He J S. 1990. Control Source Audio-Frequency Magnetotelluric[M]. Changsha: Central South University of Technology Press: 1−169 (in Chinese).
李帝铨,底青云,王光杰,李英贤,石昆法,岳安平,白大为. 2008. CSAMT探测断层在北京新区规划中的应用[J]. 地球物理学进展,23(6):1963–1969. Li D Q,Di Q Y,Wang G J,Li Y X,Shi K F,Yu A P,Bai D W. 2008. Fault detection by CSAMT and its application to new district planning in Beijing[J]. Progress in Geophysics,23(6):1963–1969 (in Chinese).
李营,杜建国,王富宽,周晓成,盘晓东,魏汝庆. 2009. 延怀盆地土壤气体地球化学特征[J]. 地震学报,31(1):82–91. doi: 10.3321/j.issn:0253-3782.2009.01.009 Li Y,Du J G,Wang F K,Zhou X C,Pan X D,Wei R Q. 2009. Geochemical characteristics of soil gas in Yanqing-Huailai basin,North China[J]. Acta Seismologica Sinica,31(1):82–91 (in Chinese).
刘菁华. 2006. 活断层上覆盖层中氡迁移的数值模拟及反演拟合[D]. 吉林: 吉林大学: 23−27. Liu J H. 2006. Numerical Simulation, Inversion Fitting of Radon Migration in the Overburden Above Active Fault[D]. Jilin: Jilin University: 23−27 (in Chinese).
马向贤,郑国东,梁收运,樊成意,王自翔,梁明亮. 2012. 地质甲烷对大气甲烷源与汇的贡献[J]. 矿物岩石地球化学通报,31(2):139–145. doi: 10.3969/j.issn.1007-2802.2012.02.007 Ma X X,Zheng G D,Liang S Y,Fan C Y,Wang Z X,Liang M L. 2012. Contributions of geologic methane to atmospheric methane sources and sinks[J]. Bulletin of Mineralogy,Petrology and Geochemistry,31(2):139–145 (in Chinese).
牟雪松,马俊,王永达,范育新. 2018. 粒度分布的端元建模分析及检验:以 " 吉兰泰—河套” 盆地西部DK-12钻孔晚第四纪沉积物为例[J]. 古地理学报,20(3):489–500. doi: 10.7605/gdlxb.2018.03.036 Mou X S,Ma J,Wang Y D,Fan Y X. 2018. End-member modeling analysis and test of grain-size distribution:A case from the Late Quaternary sediments of borehole DK-12 in the western Jilantai-Hetao basin[J]. Journal of Paleogeography,20(3):489–500 (in Chinese).
邵永新. 2012. 土壤氡方法用于断层活动性研究的讨论[J]. 中国地震,28(1):51–60. doi: 10.3969/j.issn.1001-4683.2012.01.006 Shao Y X. 2012. A discussion of fault activity research using the measurement results of soil radon[J]. Earthquake Research in China,28(1):51–60 (in Chinese).
石昆法,张庚利,李英贤,于昌明. 2001. CSAMT法在山东蓬家夼地区层间滑动角砾型金矿成矿预测中的应用[J]. 地质与勘探,37(1):86–90. doi: 10.3969/j.issn.0495-5331.2001.01.020 Shi K F,Zhang G L,Li Y X,Yu C M. 2001. Application of CSAMT method in predicting interlayer sliding breccia type gold deposits in Pengjiakuang region,Shandong Province[J]. Geology and Prospecting,37(1):86–90 (in Chinese).
谭儒蛟,胡瑞林,徐文杰,梁辉,曾如意,龚飞. 2007. 金沙江龙蟠变形体隐伏构造CSAMT探测与解译[J]. 地球物理学进展,22(1):283–288. doi: 10.3969/j.issn.1004-2903.2007.01.042 Tan R J,Hu R L,Xu W J,Liang H,Zeng R Y,Gong F. 2007. CSAMT exploration and geological interpretation of perdue tectonic structures of Longpan deformation slope in Jinsha River[J]. Progress in Geophysics,22(1):283–288 (in Chinese).
王华林,郑国东,王纪强,付海清,马向贤,胡超. 2017. 山东黄县弧形断裂带断层泥铁元素化学种分布特征及其地震地质意义[J]. 中国地震,33(2):248–259. doi: 10.3969/j.issn.1001-4683.2017.02.006 Wang H L,Zheng G D,Wang J Q,Fu H Q,Ma X X,Hu C. 2017. Iron speciation of fault gouge from the Huangxian arc fault in Shandong Province,eastern China and its seismo-geological implications[J]. Earthquake Research in China,33(2):248–259 (in Chinese).
王萍,付碧宏,张斌,孔屏,王刚. 2009. 汶川8.0级地震地表破裂带与岩性关系[J]. 地球物理学报,52(1):131–139. Wang P,Fu B H,Zhang B,Kong P,Wang G. 2009. Relationships between surface ruptures and lithologic characteristics of the Wenchuan MS8.0 earthquake[J]. Chinese Journal of Geophysics,52(1):131–139 (in Chinese).
王喜龙,李营,杜建国,陈志,周晓成,李新艳,崔月菊,王海燕,张志宏. 2017. 首都圈地区土壤气Rn,Hg,CO2地球化学特征及其成因[J]. 地震学报,39(1):85–101. doi: 10.11939/jass.2017.01.008 Wang X L,Li Y,Du J G,Chen Z,Zhou X C,Li X Y,Cui Y J,Wang H Y,Zhang Z H. 2017. Geochemical characteristics of soil gases Rn,Hg and CO2 and their genesis in the capital area of China[J]. Acta Seismologica Sinica,39(1):85–101 (in Chinese).
王云,赵慈平,冉华,陈坤华. 2015. 地壳流体CO2的释放与地震关系:回顾与展望[J]. 地震研究,38(1):119–130. doi: 10.3969/j.issn.1000-0666.2015.01.016 Wang Y,Zhao C P,Ran H,Chen K H. 2015. The relationship between the release of crustal fluid CO2 and earthquake:Retrospect and prospect[J]. Journal of Seismological Research,38(1):119–130 (in Chinese).
魏国孝. 2011. 现代吉兰泰盆地地下水演化规律及古大湖补给水源研究[D]. 兰州: 兰州大学: 1−143. Wei G X. 2011. Research on Groundwater Recharge and Evolution in Jilantai Basin and Water Supply for Jilantai-Hetao Paleo-Megalake[D]. Lanzhou: Lanzhou University: 1−143 (in Chinese).
徐伟进,高孟潭,任雪梅,冯希杰. 2008. 鄂尔多斯地块区内地震活动特征的初步研究[J]. 中国地震,24(4):388–398. doi: 10.3969/j.issn.1001-4683.2008.04.009 Xu W J,Gao M T,Ren X M,Feng X J. 2008. Study on seismic activity characteristics in the Ordos block[J]. Earthquake Research in China,24(4):388–398 (in Chinese).
杨江. 2018. 首都圈地区土壤气体地球化学特征[D]. 北京: 中国地震局地震预测研究所: 1−63. Yang J. 2018. Soil Gas Geochemistry Characteristics in the Capital Area of China[D]. Beijing: Institute of Earthquake Forecasting, China Earthquake Administration: 1−63 (in Chinese).
杨丽萍. 2008. 基于遥感与DEM的 " 吉兰泰—河套” 古大湖重建研究[D]. 兰州: 兰州大学: 1−10. Yang L P. 2008. Reconstruction of Paleo-Megalake ‘Jilantai-Hetao’ Based on Remote Sensing and DEM[D]. Lanzhou: Lanzhou University: 1−10 (in Chinese).
于昌明. 1998. CSAMT方法在寻找隐伏金矿中的应用[J]. 地球物理学报,41(1):133–138. doi: 10.3321/j.issn:0001-5733.1998.01.015 Yu C M. 1998. The application of CSAMT method in looking for hidden gold mine[J]. Acta Geophysica Sinica,41(1):133–138 (in Chinese).
张复. 2015. 吉兰泰盆地MIS 3阶段沉积环境及生态环境研究[D]. 兰州: 兰州大学: 50−60. Zhang F. 2015. The Sedimentary and Ecological Environment Research of Jilantai Basin During the MIS 3[D]. Lanzhou: Lanzhou University: 50−60 (in Chinese).
赵建明,李营,陈志,刘兆飞,赵荣琦,荣伟健. 2018. 蔚县—广灵断裂和口泉断裂气体排放和断裂活动性关系[J]. 地震地质,40(6):1402–1416. Zhao J M,Li Y,Chen Z,Liu Z F,Zhao R Q,Rong W J. 2018. Correlation between gas geochemical emission and fault activity of the Yuxian-Guangling and Kouquan faults[J]. Seismology and Geology,40(6):1402–1416 (in Chinese).
周晓成,郭文生,杜建国,王传远,刘雷. 2007. 呼和浩特地区隐伏断层土壤气氡、汞地球化学特征[J]. 地震,27(1):70–76. doi: 10.3969/j.issn.1001-8662.2007.01.010 Zhou X C,Guo W S,Du J G,Wang C Y,Liu L. 2007. The geochemical characteristics of radon and mercury in the soil gas of buried faults in the Hohhot district[J]. Earthquake,27(1):70–76 (in Chinese).
周晓成,孙凤霞,陈志,吕超甲,李静,仵柯田,杜建国. 2017. 汶川MS8.0地震破裂带CO2、CH4、Rn和Hg脱气强度[J]. 岩石学报,33(1):291–303. Zhou X C,Sun F X,Chen Z,Lü C J,Li J,Wu K T,Du J G. 2017. Degassing of CO2,CH4,Rn and Hg in the rupture zones produced by Wenchuan MS8.0 earthquake[J]. Acta Petrologica Sinica,33(1):291–303 (in Chinese).
Annunziatellis A,Beaubien S E,Bigi S,Ciotoli G,Coltella M,Lombardi S. 2008. Gas migration along fault systems and through the vadose zone in the Latera caldera (central Italy):Implications for CO2 geological storage[J]. Int J Greenh Gas Con,2(3):353–372. doi: 10.1016/j.ijggc.2008.02.003
Baixeras C,Erlandsson B,Font L,Jönsson G. 2001. Radon emanation from soil samples[J]. Radiat Meas,34(1/6):441–443.
Baubron J C,Rigo A,Toutain J P. 2002. Soil gas profiles as a tool to characterise active tectonic areas:The Jaut Pass example (Pyrenees,France)[J]. Earth Planet Sci Lett,196(1/2):69–81.
Becken M,Ritter O,Park S K,Bedrosian P A,Weckmann U,Weber M. 2008. A deep crustal fluid channel into the San Andreas fault system near Parkfield,California[J]. Geophys J Int,173(2):718–732. doi: 10.1111/j.1365-246X.2008.03754.x
Chen Z,Zhou X,Du J,Xie C,Liu L,Li Y,Yi L,Liu H,Cui Y. 2015. Hydrochemical characteristics of hot spring waters in the Kangding district related to the Lushan MS=7.0 earthquake in Sichuan,China[J]. Nat Hazards Earth Syst Sci,15(6):1149–1156. doi: 10.5194/nhess-15-1149-2015
Chen Z,Li Y,Liu Z F,Wang J,Zhou X C,Du J G. 2018. Radon emission from soil gases in the active fault zones in the capital of China and its environmental effects[J]. Sci Rep,8(1):16772. doi: 10.1038/s41598-018-35262-1
Chen Z,Li Y,Liu Z F,Zheng G D,Xu W,Yan W,Yi L. 2019. CH4 and CO2 emissions from mud volcanoes on the southern margin of the Junggar Basin,NW China:Origin,output,and relation to regional tectonics[J]. J Geophys Res,124(5):1–15. doi: 10.1029/2018JB016822
Etiope G,Martinelli G. 2002. Migration of carrier and trace gases in the geosphere:An overview[J].Phys Earth Planet Inter,129(3/4):185–204.
Faulkner D R,Lewis A C,Rutter E H. 2003. On the internal structure and mechanics of large strike-slip fault zones:Field observations of the Carboneras fault in southeastern Spain[J]. Tectonophysics,367(3/4):235–251.
Finizola A,Aubert M,Revil A,Schütze C,Sortino F. 2009. Importance of structural history in the summit area of Stromboli during the 2002−2003 eruptive crisis inferred from temperature,soil CO2,self-potential,and electrical resistivity tomography[J]. J Volcanol Geoth Res,183(3/4):213–227.
Fu C C,Yang T F,Chen C H,Lee L C,Wu Y M,Liu T K,Walia V,Kumar A,Lai T H. 2017. Spatial and temporal anomalies of soil gas in northern Taiwan and its tectonic and seismic implications[J]. J Asian Earth Sci,149:64–77. doi: 10.1016/j.jseaes.2017.02.032
Ghosh D,Deb A,Sengupta R. 2009. Anomalous radon emission as precursor of earthquake[J]. J Appl Geophys,69(2):67–81. doi: 10.1016/j.jappgeo.2009.06.001
Giammanco S,Immè G,Mangano G,Morelli D,Neri M. 2009. Comparison between different methodologies for detecting radon in soil along an active fault:The case of the Pernicana fault system,Mt. Etna (Italy)[J]. Appl Radiat Isotopes,67(1):178–185. doi: 10.1016/j.apradiso.2008.09.007
Han X,Li Y,Du J,Zhou X,Xie C,Zhang W. 2014. Rn and CO2 geochemistry of soil gas across the active fault zones in the capital area of China[J]. Nat Hazards Earth Syst Sci,14(10):2803–2815. doi: 10.5194/nhess-14-2803-2014
Irwin W P,Barnes I. 1980. Tectonic relations of carbon dioxide discharges and earthquakes[J]. J Geophys Res,85(B6):3115–3121. doi: 10.1029/JB085iB06p03115
Italiano F,Bonfanti P,Ditta M,Petrini R,Slejko F. 2009. Helium and carbon isotopes in the dissolved gases of Friuli region (NE Italy):Geochemical evidence of CO2 production and degassing over a seismically active area[J]. Chem Geol,266(1/2):76–85.
King C Y. 1986. Gas geochemistry applied to earthquake prediction:An overview[J]. J Geophys Res,91(B12):12269–12281. doi: 10.1029/JB091iB12p12269
King C Y,King B S,Evans W C,Zhang W. 1996. Spatial radon anomalies on active faults in California[J]. Appl Geochem,11(4):497–510. doi: 10.1016/0883-2927(96)00003-0
Lehmann B E,Lehmann M,Neftel A,Tarakanov S V. 2000. Radon-222 monitoring of soil diffusivity[J]. Geophys Res Lett,27(23):3917–3920. doi: 10.1029/1999GL008469
Lehmann B E,Ihly B,Salzmann S,Conen F,Simon E. 2004. An automatic static chamber for continuous 220Rn and 222Rn flux measurements from soil[J]. Radiat Meas,38(1):43–50. doi: 10.1016/j.radmeas.2003.08.001
Li Y,Du J G,Wang X,Zhou X C,Xie C,Cui Y J. 2013. Spatial variations of soil gas geochemistry in the Tangshan area of northern China[J]. Terr Atmos Ocean Sci,24(3):323–332. doi: 10.3319/TAO.2012.11.26.01(TT)
Ma X X,Zheng G D,Liang S Y,Xu W. 2015. Geochemical characteristics of absorbed gases in fault gouge from the Daliushu Dam area,NW China[J]. Geochem J,49(4):413–419. doi: 10.2343/geochemj.2.0365
Papp B,Deák F,Horváth Á,Kiss Á,Rajnai G,Szabó C. 2008. A new method for the determination of geophysical parameters by radon concentration measurements in bore-hole[J]. J Environ Radioactiv,99(11):1731–1735. doi: 10.1016/j.jenvrad.2008.05.005
Revil A,Finizola A,Sortino F,Ripepe M. 2004. Geophysical investigations at Stromboli volcano,Italy:Implications for ground water flow and paroxysmal activity[J]. Geophys J Int,157(1):426–440. doi: 10.1111/j.1365-246X.2004.02181.x
Schütze C,Vienken T,Werban U,Dietrich P,Finizola A,Leven C. 2012. Joint application of geophysical methods and direct push-soil gas surveys for the improved delineation of buried fault zones[J]. J Appl Geophys,82:129–136. doi: 10.1016/j.jappgeo.2012.03.002
Seminsky K Z,Bobrov A A. 2009. Radon activity of faults (western Baikal and southern Angara areas)[J]. Russ Geol Geophys,50(8):682–692. doi: 10.1016/j.rgg.2008.12.010
Seminsky K Z,Demberel S. 2013. The first estimations of soil-radon activity near faults in Central Mongolia[J]. Radiat Meas,49(1):19–34.
Seminsky K Z,Bobrov A A,Demberel S. 2014. Variations in radon activity in the crustal fault zones:Spatial characteristics[J]. Izv-Phys Solid Eart+,50(6):795–813. doi: 10.1134/S1069351314060081
Sun X L,Yang P T,Xiang Y,Si X Y,Liu D Y. 2018. Across-fault distributions of radon concentrations in soil gas for different tectonic environments[J]. Geosci J,22(2):227–239. doi: 10.1007/s12303-017-0028-2
Toutain J P,Baubron J C. 1999. Gas geochemistry and seismotectonics:A review[J]. Tectonophysics,304(1/2):1–27.
Wang D Y,He L,Shi X J,Wei S Q,Feng X B. 2006. Release flux of mercury from different environmental surfaces in Chongqing,China[J]. Chemosphere,64(11):1845–1854. doi: 10.1016/j.chemosphere.2006.01.054
Winkler R,Ruckerbauer F,Bunzl K. 2001. Radon concentration in soil gas:A comparison of the variability resulting from different methods,spatial heterogeneity and seasonal fluctuations[J]. Sci Total Environ,272(1/3):273–282.
Woodruff L G,Cannon W F,Eberl D D,Smith D B,Kilburn J E,Horton J D,Garrett R G,Klassen R A. 2009. Continental-scale patterns in soil geochemistry and mineralogy:Results from two transects across the United States and Canada[J]. Appl Geochem,24(8):1369–1381. doi: 10.1016/j.apgeochem.2009.04.009
Yang Y,Li Y,Guan Z J,Chen Z,Zhang L,Lü C J,Sun F X. 2018. Correlations between the radon concentrations in soil gas and the activity of the Anninghe and the Zemuhe faults in Sichuan,southwestern of China[J]. Appl Geochem,89:23–33. doi: 10.1016/j.apgeochem.2017.11.006
Zarroca M,Linares R,Bach J,Roqué C,Moreno V,Font L,Baixeras C. 2012. Integrated geophysics and soil gas profiles as a tool to characterize active faults:The Amer fault example (Pyrenees,NE Spain)[J].Environ Earth Sci,67(3):889–910. doi: 10.1007/s12665-012-1537-y
Zheng G D,Fu B H,Takahashi Y,Miyahara M,Kuno A,Matsuo M,Miyashita Y. 2008. Iron speciation in fault gouge from the Ushikubi fault zone central Japan[J]. Hyperfine Interact,186(1/3):39–52.
Zheng G D,Xu S,Liang S Y,Shi P L,Zhao J. 2013. Gas emission from the Qingzhu River after the 2008 Wenchuan earthquake,Southwest China[J]. Chem Geol,339:187–193. doi: 10.1016/j.chemgeo.2012.10.032
Zhou X C,Du J G,Chen Z,Cheng J W,Tang Y,Yang L M,Xie C,Cui Y J,Liu L,Yi L,Yang P X,Li Y. 2010. Geochemistry of soil gas in the seismic fault zone produced by the Wenchuan MS8.0 earthquake,southwestern China[J]. Geochem Trans,11(1):5. doi: 10.1186/1467-4866-11-5
Zhou X C,Chen Z,Cui Y J. 2016. Environmental impact of CO2,Rn,Hg degassing from the rupture zones produced by Wenchuan MS8.0 earthquake in western Sichuan,China[J]. Environ Geochem Health,38(5):1067–1082. doi: 10.1007/s10653-015-9773-1