Abstract
A TDEM (time domain electromagnetic) surveillance was conducted for the Hachijo Island region, Tokyo. The survey covered a 70 km{sup 2} area, with 81 observation stations. There was a distance of 1 km or more between transmission electrodes, the signal was a rectangular wave with a cycle of 16 seconds or more, the sending current was 60 A or more, and the shortest distance between a transmission electrode and an observation station was 2.5 km or more. A subsurface structure model was proposed after the analysis of the collected data, which is described below. In the Mt. Nishiyama district, the deep-seated magnetic substance, high-conduction zone, and the low gravity anomaly zone were found to be roughly equal to each other in terms of distribution. It is inferred that the low gravity anomaly results from reduction in resistivity by the progress of fractioning of rocks due to the intrusion of a magnetized rock into the depth and from mass defect due to volcanic eruption. In the Mt. Higashiyama district, a high density rock intrudes in the ENE-WSW direction for the creation of a high gravity anomaly belt, and it is inferred that alteration occurred along the southern rim of the belt,
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Citation Formats
None.
Fiscal 1989 geothermal development promotion survey report. Data sampled by ground based survey and attached to the report (Electromagnetic surveillance - TDEM - No. 32. Hachijo Island region); Chinetsu kaihatsu sokushin chosa chijo chosa hokokusho futai shiryo. 1989 nendo chinetsu kaihatsu sokushin chosa denji tansa (TDEM ho) hokokusho (No. 32 Hachijojima chiiki).
Japan: N. p.,
1989.
Web.
None.
Fiscal 1989 geothermal development promotion survey report. Data sampled by ground based survey and attached to the report (Electromagnetic surveillance - TDEM - No. 32. Hachijo Island region); Chinetsu kaihatsu sokushin chosa chijo chosa hokokusho futai shiryo. 1989 nendo chinetsu kaihatsu sokushin chosa denji tansa (TDEM ho) hokokusho (No. 32 Hachijojima chiiki).
Japan.
None.
1989.
"Fiscal 1989 geothermal development promotion survey report. Data sampled by ground based survey and attached to the report (Electromagnetic surveillance - TDEM - No. 32. Hachijo Island region); Chinetsu kaihatsu sokushin chosa chijo chosa hokokusho futai shiryo. 1989 nendo chinetsu kaihatsu sokushin chosa denji tansa (TDEM ho) hokokusho (No. 32 Hachijojima chiiki)."
Japan.
@misc{etde_20316266,
title = {Fiscal 1989 geothermal development promotion survey report. Data sampled by ground based survey and attached to the report (Electromagnetic surveillance - TDEM - No. 32. Hachijo Island region); Chinetsu kaihatsu sokushin chosa chijo chosa hokokusho futai shiryo. 1989 nendo chinetsu kaihatsu sokushin chosa denji tansa (TDEM ho) hokokusho (No. 32 Hachijojima chiiki)}
author = {None}
abstractNote = {A TDEM (time domain electromagnetic) surveillance was conducted for the Hachijo Island region, Tokyo. The survey covered a 70 km{sup 2} area, with 81 observation stations. There was a distance of 1 km or more between transmission electrodes, the signal was a rectangular wave with a cycle of 16 seconds or more, the sending current was 60 A or more, and the shortest distance between a transmission electrode and an observation station was 2.5 km or more. A subsurface structure model was proposed after the analysis of the collected data, which is described below. In the Mt. Nishiyama district, the deep-seated magnetic substance, high-conduction zone, and the low gravity anomaly zone were found to be roughly equal to each other in terms of distribution. It is inferred that the low gravity anomaly results from reduction in resistivity by the progress of fractioning of rocks due to the intrusion of a magnetized rock into the depth and from mass defect due to volcanic eruption. In the Mt. Higashiyama district, a high density rock intrudes in the ENE-WSW direction for the creation of a high gravity anomaly belt, and it is inferred that alteration occurred along the southern rim of the belt, that magnetic substance was produced in the cavity-abundant portion, and that a volcano with several craters rose at the middle of the portion. (NEDO)}
place = {Japan}
year = {1989}
month = {Nov}
}
title = {Fiscal 1989 geothermal development promotion survey report. Data sampled by ground based survey and attached to the report (Electromagnetic surveillance - TDEM - No. 32. Hachijo Island region); Chinetsu kaihatsu sokushin chosa chijo chosa hokokusho futai shiryo. 1989 nendo chinetsu kaihatsu sokushin chosa denji tansa (TDEM ho) hokokusho (No. 32 Hachijojima chiiki)}
author = {None}
abstractNote = {A TDEM (time domain electromagnetic) surveillance was conducted for the Hachijo Island region, Tokyo. The survey covered a 70 km{sup 2} area, with 81 observation stations. There was a distance of 1 km or more between transmission electrodes, the signal was a rectangular wave with a cycle of 16 seconds or more, the sending current was 60 A or more, and the shortest distance between a transmission electrode and an observation station was 2.5 km or more. A subsurface structure model was proposed after the analysis of the collected data, which is described below. In the Mt. Nishiyama district, the deep-seated magnetic substance, high-conduction zone, and the low gravity anomaly zone were found to be roughly equal to each other in terms of distribution. It is inferred that the low gravity anomaly results from reduction in resistivity by the progress of fractioning of rocks due to the intrusion of a magnetized rock into the depth and from mass defect due to volcanic eruption. In the Mt. Higashiyama district, a high density rock intrudes in the ENE-WSW direction for the creation of a high gravity anomaly belt, and it is inferred that alteration occurred along the southern rim of the belt, that magnetic substance was produced in the cavity-abundant portion, and that a volcano with several craters rose at the middle of the portion. (NEDO)}
place = {Japan}
year = {1989}
month = {Nov}
}