Pub Date : 2008-10-25DOI: 10.5026/JGEOGRAPHY.117.851
英輝 小坂, 京子 楮原, 敦志 三輪, 俊文 今泉, 英樹 黒澤, 壯 野原
We reconstruct the evolution of the active fault zone at Yokote Basin in northeast Japan based on new fission-track ages. The active fault zone consists of Obonai, Shiraiwa, and Senya faults. Fission-track dating was carried out from the late Pliocene to Pleistocene strata, developing along the active fault zone consisting of these faults. The number of samples was five. (1) Fission-track age of 1.5 ± 0.1 Ma (OB-03) was obtained from welded tuff in the Tazawa Formation around the Obonai fault. (2) Fission-track age of 1.85 ± 0.13 Ma (YG-01) was obtained from tuff in the Tazawa Formation around the south of the Obonai fault. (3) Fission-track age of 1.6 ± 0.3 Ma (FT-01) was obtained from the Kurisawa Formation around the Shiraiwa fault. (4, 5) Fission-track ages of 0.93 ± 0.14 Ma (FT-02) and 2.7 ± 0.4 Ma (FT-03) were obtained from tuffs in the Senya Formation around the Senya fault. YG-01 and FT-03 are likely to be young because of the possibility of reworked zircon crystals. As a result of making balanced and restored cross-sections across the active fault zone, the western boundary fault of the Mahiru mountains moves in the active fault zone after the frontal fault movements. Obonai and Shiraiwa faults were moved by the western boundary fault of the Mahiru mountains when the Senya fault began movement of the frontal fault.
根据新的裂变径迹时代，重建了日本东北部横手盆地活动断裂带的演化过程。活动断裂带由小盆内断裂、白洼断裂和仙崖断裂组成。沿这些断裂组成的活动断裂带发育的晚上新世至更新世地层进行了裂变径迹测年。样本数为5。(1) Obonai断裂带附近Tazawa组焊接凝灰岩的裂变径迹年龄为1.5±0.1 Ma (OB-03)。(2) Obonai断裂带南缘太泽组凝灰岩的裂变径迹年龄为1.85±0.13 Ma (YG-01)。(3)在Shiraiwa断裂周围的Kurisawa组获得了1.6±0.3 Ma (FT-01)的裂变径迹年龄。(4,5) Senya组凝灰岩的裂变径迹年龄分别为0.93±0.14 Ma (FT-02)和2.7±0.4 Ma (FT-03)。YG-01和FT-03可能是年轻的，因为锆石晶体可能被改造过。由于在活动断裂带上做了平衡和恢复的横截面，马日鲁山西界断裂在锋面断层运动后在活动断裂带内移动。当仙崖断裂开始前缘断裂运动时，小盆内断裂和白洼断裂被马尻山西界断裂移动。
{"title":"横手盆地東縁断層帯の後期鮮新統～更新統のフィッション・トラック年代","authors":"英輝 小坂, 京子 楮原, 敦志 三輪, 俊文 今泉, 英樹 黒澤, 壯 野原","doi":"10.5026/JGEOGRAPHY.117.851","DOIUrl":"https://doi.org/10.5026/JGEOGRAPHY.117.851","url":null,"abstract":"We reconstruct the evolution of the active fault zone at Yokote Basin in northeast Japan based on new fission-track ages. The active fault zone consists of Obonai, Shiraiwa, and Senya faults. Fission-track dating was carried out from the late Pliocene to Pleistocene strata, developing along the active fault zone consisting of these faults. The number of samples was five. (1) Fission-track age of 1.5 ± 0.1 Ma (OB-03) was obtained from welded tuff in the Tazawa Formation around the Obonai fault. (2) Fission-track age of 1.85 ± 0.13 Ma (YG-01) was obtained from tuff in the Tazawa Formation around the south of the Obonai fault. (3) Fission-track age of 1.6 ± 0.3 Ma (FT-01) was obtained from the Kurisawa Formation around the Shiraiwa fault. (4, 5) Fission-track ages of 0.93 ± 0.14 Ma (FT-02) and 2.7 ± 0.4 Ma (FT-03) were obtained from tuffs in the Senya Formation around the Senya fault. YG-01 and FT-03 are likely to be young because of the possibility of reworked zircon crystals. As a result of making balanced and restored cross-sections across the active fault zone, the western boundary fault of the Mahiru mountains moves in the active fault zone after the frontal fault movements. Obonai and Shiraiwa faults were moved by the western boundary fault of the Mahiru mountains when the Senya fault began movement of the frontal fault.","PeriodicalId":356213,"journal":{"name":"Chigaku Zasshi (jounal of Geography)","volume":"193 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121739420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-10-25DOI: 10.5026/JGEOGRAPHY.117.894
洋一 笹井, 誠 原田, Julio P. Sabit, J. Zlotnicki, 良和 田中, Juan M. Cordon, 誠也 上田, 年恭 長尾, Jame S. Sincioco
A geomagnetic and topographic survey of the Main Crater Lake (MCL) on Volcano Island, Taal volcano, the Philippines, was conducted to identify the eruption mechanism of the volcano. A mound at the lake bottom was found near the northern part of MCL, which was not present at the 1986 survey. Called mound M, it was formed between 1986 and 2008 during a period of new fumarole activity, which started on the northeastern shore of MCL in the early 1990's. A geomagnetic survey found no Total Magnetic Field (TMF) anomaly corresponding to the mound, which implies that mound M is non-magnetic. The site coincides with the location of a high-temperature area detected by the ASTER satellite during the early 2005 volcanic crisis. The mound M might contain chemicals (chloride or sulphide?) deposited from volcanic gas. Two continuously-recording proton magnetometers were set up at two geothermal areas on Volcano Island. Recordings of TMF variations obtained over six months on Volcano Island showed excellent stability and precision for monitoring the volcanic activity.
对菲律宾塔阿尔火山岛上的主火山口湖(Main Crater Lake, MCL)进行了地磁和地形测量，以确定该火山的喷发机制。在MCL北部附近的湖底发现了一个土丘，这在1986年的调查中没有出现。它被称为M丘，形成于1986年至2008年之间，在1990年代初MCL东北岸开始的新喷气孔活动期间。地磁测量未发现与土丘对应的总磁场(TMF)异常，说明土丘M是非磁性的。该地点与2005年初火山危机期间ASTER卫星探测到的高温区域的位置一致。M丘可能含有火山气体沉积的化学物质(氯化物或硫化物?)在火山岛的两个地热区设置了两台连续记录的质子磁力计。在火山岛上6个月的TMF变化记录显示了监测火山活动的良好稳定性和精度。
{"title":"フィリピン・タール火山・主火口湖の磁気および水深測量 : 序報","authors":"洋一 笹井, 誠 原田, Julio P. Sabit, J. Zlotnicki, 良和 田中, Juan M. Cordon, 誠也 上田, 年恭 長尾, Jame S. Sincioco","doi":"10.5026/JGEOGRAPHY.117.894","DOIUrl":"https://doi.org/10.5026/JGEOGRAPHY.117.894","url":null,"abstract":"A geomagnetic and topographic survey of the Main Crater Lake (MCL) on Volcano Island, Taal volcano, the Philippines, was conducted to identify the eruption mechanism of the volcano. A mound at the lake bottom was found near the northern part of MCL, which was not present at the 1986 survey. Called mound M, it was formed between 1986 and 2008 during a period of new fumarole activity, which started on the northeastern shore of MCL in the early 1990's. A geomagnetic survey found no Total Magnetic Field (TMF) anomaly corresponding to the mound, which implies that mound M is non-magnetic. The site coincides with the location of a high-temperature area detected by the ASTER satellite during the early 2005 volcanic crisis. The mound M might contain chemicals (chloride or sulphide?) deposited from volcanic gas. Two continuously-recording proton magnetometers were set up at two geothermal areas on Volcano Island. Recordings of TMF variations obtained over six months on Volcano Island showed excellent stability and precision for monitoring the volcanic activity.","PeriodicalId":356213,"journal":{"name":"Chigaku Zasshi (jounal of Geography)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128525491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-10-11DOI: 10.5026/jgeography.117.734
Z. Xue, T. Matsuoka
Several key questions need to be answered when CO2 geological storage is to be undertaken worldwide. How should CO2 be stored underground? Can trapping be assumed in saline formations and can CO2 be retained for long periods safely in the subsurface? The first Japanese pilot-scale CO2 sequestration project in Nagaoka was undertaken to provide answers to these questions. The injection site is located at the Minami-Nagaoka gas field in Nagaoka City, 200km north of Tokyo. Supercritical CO2 was injected into an onshore saline aquifer at a depth of 1,100m. CO2 was injected at a rate of 20 to 40 tonnes per day over an 18-month period, with a cumulative amount of 10,400 tonnes. A series of monitoring activities, which consisted of time-lapse well logging, crosswell seismic tomography, 3D seismic survey and formation fluid sampling, was carried out successfully to monitor CO2 movement in the sandstone reservoir. This paper presents an overview of the results obtained from both field and laboratory studies to examine the spatial-time distribution of CO2 and various trapping mechanisms in the reservoir. CO2 breakthrough at two of the three observation wells was clearly identified by changes in resistivity, sonic P-wave velocity and neutron porosity from time-lapse well logging. Each velocity difference tomogram obtained by crosswell seismic tomography showed a striking anomaly area around the injection well. As the amount of injected CO2 increased, the low-velocity zone expanded preferentially along the formation up-dip direction during the first two monitoring surveys and less change around the CO2-bearing zone could be confirmed from the following surveys. Unfortunately there was no significant change in 3D seismic results due to CO2 injection. The pilot-scale project demonstrated that CO2 can be injected into a deep saline aquifer without adverse health, safety or environmental effects. The Nagaoka project also provides unique data to develop economically viable, environmentally effective options for reducing carbon emissions in Japan.
{"title":"Lessons from the First Japanese Pilot Project on Saline Aquifer CO2 Storage","authors":"Z. Xue, T. Matsuoka","doi":"10.5026/jgeography.117.734","DOIUrl":"https://doi.org/10.5026/jgeography.117.734","url":null,"abstract":"Several key questions need to be answered when CO2 geological storage is to be undertaken worldwide. How should CO2 be stored underground? Can trapping be assumed in saline formations and can CO2 be retained for long periods safely in the subsurface? The first Japanese pilot-scale CO2 sequestration project in Nagaoka was undertaken to provide answers to these questions. The injection site is located at the Minami-Nagaoka gas field in Nagaoka City, 200km north of Tokyo. Supercritical CO2 was injected into an onshore saline aquifer at a depth of 1,100m. CO2 was injected at a rate of 20 to 40 tonnes per day over an 18-month period, with a cumulative amount of 10,400 tonnes. A series of monitoring activities, which consisted of time-lapse well logging, crosswell seismic tomography, 3D seismic survey and formation fluid sampling, was carried out successfully to monitor CO2 movement in the sandstone reservoir. This paper presents an overview of the results obtained from both field and laboratory studies to examine the spatial-time distribution of CO2 and various trapping mechanisms in the reservoir. CO2 breakthrough at two of the three observation wells was clearly identified by changes in resistivity, sonic P-wave velocity and neutron porosity from time-lapse well logging. Each velocity difference tomogram obtained by crosswell seismic tomography showed a striking anomaly area around the injection well. As the amount of injected CO2 increased, the low-velocity zone expanded preferentially along the formation up-dip direction during the first two monitoring surveys and less change around the CO2-bearing zone could be confirmed from the following surveys. Unfortunately there was no significant change in 3D seismic results due to CO2 injection. The pilot-scale project demonstrated that CO2 can be injected into a deep saline aquifer without adverse health, safety or environmental effects. The Nagaoka project also provides unique data to develop economically viable, environmentally effective options for reducing carbon emissions in Japan.","PeriodicalId":356213,"journal":{"name":"Chigaku Zasshi (jounal of Geography)","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123795853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-08-25DOI: 10.5026/JGEOGRAPHY.117.697
俊和 田村, 富士 稲崎, 信夫 下司, 浩一 下川, 俊彦 須貝, 和敏 中島
A strong earthquake of M7.2 (MW6.7-6.9) occurred on 14 June 2008 in the north-central part of Northeastern Japan. It was named the Iwate-Miyagi Nairiku Earthquake in 2008. Several seismic models show a 25-30km long reverse fault in the NNE-SSW direction and a westward inclination. Although some geological thrusts with a similar trend are known, as shown in Fig. 1, none of them has been recognized as an active fault. Surface faults associated with the earthquake were found at several points along the geological thrusts. The quake induced many mass-movements in the mountainous and hilly area, which is composed mostly of Neogene to Pleistocene volcaniclastic rocks (Fig. 1), near the seismic fault and particularly on the western side (upper block). Most of the damage caused by the earthquake was closely connected to mass-movements. A large-scale block glide amounting to about 7×107m3 in the volume of dislocated mass (Figs. 2, 3) occurred in the northern half of the pre-existing landslide area composed of poorly-consolidated pyroclastic flow deposits with a welded cap around 5Ma (Np3 in Fig. 1). The almost horizontal slip surface of the glide is considered to have been formed in the underlying lacustrine beds. A large collapse, occurring at a slope on which snow remained on Kurikoma Volcano, composed of Quaternary andesitic lavas and pyroclastics (Qm2 in Fig. 1), formed a debris flow (Fig. 4) which buried a lodge at Komanoyu Spa. Many landslides checked river channels. One of them was observed at Ogawara, where a slide of a spur composed of Pleistocene pyroclastic deposits checked the Ichihasama River (Fig. 5). The collapse of Matsurube Bridge, a three-span 95 m-long bridge over a tributary of the Iwai River, was also entirely caused by a landslide at the north-facing slope of a narrow ridge (Fig. 6). A surface fault appeared in rice fields at Mochikorobashi on the side of a tributary of the Koromo River (Fig. 7). The trace of the water's edge and lines of planted rice indicate a co-seismic uplift and a right-lateral offset with a clockwise turn of the trend (Fig. 8).
{"title":"岩手・宮城内陸地震（2008年6月14日）による地変（速報）","authors":"俊和 田村, 富士 稲崎, 信夫 下司, 浩一 下川, 俊彦 須貝, 和敏 中島","doi":"10.5026/JGEOGRAPHY.117.697","DOIUrl":"https://doi.org/10.5026/JGEOGRAPHY.117.697","url":null,"abstract":"A strong earthquake of M7.2 (MW6.7-6.9) occurred on 14 June 2008 in the north-central part of Northeastern Japan. It was named the Iwate-Miyagi Nairiku Earthquake in 2008. Several seismic models show a 25-30km long reverse fault in the NNE-SSW direction and a westward inclination. Although some geological thrusts with a similar trend are known, as shown in Fig. 1, none of them has been recognized as an active fault. Surface faults associated with the earthquake were found at several points along the geological thrusts. The quake induced many mass-movements in the mountainous and hilly area, which is composed mostly of Neogene to Pleistocene volcaniclastic rocks (Fig. 1), near the seismic fault and particularly on the western side (upper block). Most of the damage caused by the earthquake was closely connected to mass-movements. A large-scale block glide amounting to about 7×107m3 in the volume of dislocated mass (Figs. 2, 3) occurred in the northern half of the pre-existing landslide area composed of poorly-consolidated pyroclastic flow deposits with a welded cap around 5Ma (Np3 in Fig. 1). The almost horizontal slip surface of the glide is considered to have been formed in the underlying lacustrine beds. A large collapse, occurring at a slope on which snow remained on Kurikoma Volcano, composed of Quaternary andesitic lavas and pyroclastics (Qm2 in Fig. 1), formed a debris flow (Fig. 4) which buried a lodge at Komanoyu Spa. Many landslides checked river channels. One of them was observed at Ogawara, where a slide of a spur composed of Pleistocene pyroclastic deposits checked the Ichihasama River (Fig. 5). The collapse of Matsurube Bridge, a three-span 95 m-long bridge over a tributary of the Iwai River, was also entirely caused by a landslide at the north-facing slope of a narrow ridge (Fig. 6). A surface fault appeared in rice fields at Mochikorobashi on the side of a tributary of the Koromo River (Fig. 7). The trace of the water's edge and lines of planted rice indicate a co-seismic uplift and a right-lateral offset with a clockwise turn of the trend (Fig. 8).","PeriodicalId":356213,"journal":{"name":"Chigaku Zasshi (jounal of Geography)","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132558234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-08-25DOI: 10.5026/JGEOGRAPHY.117.768
康子 奥山, 宗建 佐々木, 洋文 村岡, 信行 金子, 正夫 徂徠
The geochemical characteristics of deep groundwater, or formation water, are essential in all processes of geochemical trapping in an open aquifer CO2 storage. We have been constructing a database of groundwater chemical compositions in deep aquifers in Japan (“Formation-water database”). The database have two major objectives; (1) to be a dataset on groundwater of reservoir depths for evaluating CO2 solubility; and, (2) providing model water compositions for geochemical modeling and experiments in our study of underground CO2 storage. More than 2600 datasets are collected from literature on geochemistry of groundwater reported from 10 selected areas in Japan; the areas of investigation include populated cities in which large point sources of CO2 are located. The accumulated data indicate that groungwater of reservoir depth (>800m) is generally dilute in composition compared to average seawater, suggesting a high potential of CO2 solubility. Systematic geochemical differences are also observed between groundwater hosted in marine and freshwater sediments.
{"title":"CO2帯水層貯留での「地層水」の役割とわが国でのCO2地化学トラッピングへの適用性","authors":"康子 奥山, 宗建 佐々木, 洋文 村岡, 信行 金子, 正夫 徂徠","doi":"10.5026/JGEOGRAPHY.117.768","DOIUrl":"https://doi.org/10.5026/JGEOGRAPHY.117.768","url":null,"abstract":"The geochemical characteristics of deep groundwater, or formation water, are essential in all processes of geochemical trapping in an open aquifer CO2 storage. We have been constructing a database of groundwater chemical compositions in deep aquifers in Japan (“Formation-water database”). The database have two major objectives; (1) to be a dataset on groundwater of reservoir depths for evaluating CO2 solubility; and, (2) providing model water compositions for geochemical modeling and experiments in our study of underground CO2 storage. More than 2600 datasets are collected from literature on geochemistry of groundwater reported from 10 selected areas in Japan; the areas of investigation include populated cities in which large point sources of CO2 are located. The accumulated data indicate that groungwater of reservoir depth (>800m) is generally dilute in composition compared to average seawater, suggesting a high potential of CO2 solubility. Systematic geochemical differences are also observed between groundwater hosted in marine and freshwater sediments.","PeriodicalId":356213,"journal":{"name":"Chigaku Zasshi (jounal of Geography)","volume":"117 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129505045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-06-25DOI: 10.5026/jgeography.117.668
I. Kaneoka
Based on radiogenic isotopes, we can obtain information about the Earth related to time. Radiometric dating is a typical example. Due to the advanced development of current analytical techniques, radiometric ages covering the Earth's entire history can be obtained with an error of less than 1 ％ , even for a mineral crystal. However, there still remain problems to be clarified including the reliability of decay constants and the meanings of value obtained. In another approach, an isotope ratio including a radiogenic isotope can be used to clarify the evolution of the Earth. By applying multiple isotope systematics for typical volcanic rocks such as Mid-oceanic ridge basalts （ MORBs ） and oceanic island basalts （ OIBs ） , we conjecture the chemical state of the Earth's interior such as the degree of chemical fractionation and degassing. As an additional material used for clarifying the Earth's deep interior, I demonstrate the significance of kimberlites which might reflect the state of the Earth's deep interior more directly than OIBs.
{"title":"Research for the Earth Using \"Time\" as a Weapon: Present Status of Dating and Clarifying the Chemical State of the Earth's Deep Interior Based on Isotope Ratios","authors":"I. Kaneoka","doi":"10.5026/jgeography.117.668","DOIUrl":"https://doi.org/10.5026/jgeography.117.668","url":null,"abstract":"Based on radiogenic isotopes, we can obtain information about the Earth related to time. Radiometric dating is a typical example. Due to the advanced development of current analytical techniques, radiometric ages covering the Earth's entire history can be obtained with an error of less than 1 ％ , even for a mineral crystal. However, there still remain problems to be clarified including the reliability of decay constants and the meanings of value obtained. In another approach, an isotope ratio including a radiogenic isotope can be used to clarify the evolution of the Earth. By applying multiple isotope systematics for typical volcanic rocks such as Mid-oceanic ridge basalts （ MORBs ） and oceanic island basalts （ OIBs ） , we conjecture the chemical state of the Earth's interior such as the degree of chemical fractionation and degassing. As an additional material used for clarifying the Earth's deep interior, I demonstrate the significance of kimberlites which might reflect the state of the Earth's deep interior more directly than OIBs.","PeriodicalId":356213,"journal":{"name":"Chigaku Zasshi (jounal of Geography)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116976279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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