Improved accuracy in high-frequency AC transport measurements in pulsed high magnetic fields

We show theoretically and experimentally that accurate transport measurements are possible even within the short time provided by pulsed magnetic fields. For this purpose, a new method has been devised, which removes the noise component of a specific frequency from the signal by taking a linear combination of the results of numerical phase detection using multiple integer periods. We also established a method to unambiguously determine the phase rotation angle in AC transport measurements using a frequency range of tens of kilohertz. We revealed that the dominant noise in low-frequency transport measurements in pulsed magnetic fields is the electromagnetic induction caused by mechanical vibrations of wire loops in inhomogeneous magnetic fields. These results strongly suggest that accurate transport measurements in short-pulsed magnets are possible when mechanical vibrations are well suppressed

Seismic exploration at Fuji volcano with active sources : The outline of the experiment and the arrival time data

Fuji volcano (altitude 3,776m) is the largest basaltic stratovolcano in Japan. In late August and early September 2003, seismic exploration was conducted around Fuji volcano by the detonation of 500 kg charges of dynamite to investigate the seismic structure of that area. Seismographs with an eigenfrequency of 2 Hz were used for observation, positioned along a WSW-ENE line passing through the summit of the mountain. A total of 469 seismic stations were installed at intervals of 250-500 m. The data were stored in memory on-site using data loggers. The sampling interval was 4 ms. Charges were detonated at 5 points, one at each end of the observation line and 3 along its length. The first arrival times and the later-phase arrival times at each station for each detonation were recorded as data. P-wave velocities in the surface layer were estimated from the travel time curves near the explosion points, with results of 2.5 km/s obtained for the vicinity of Fuji volcano and 4.0 km5/s elsewhere

Unzen Volcano : the 1900-1992 eruption

1.Chronological Table 2.Photographic Records of the 1990-1992 Eruptions at Unzen Volcano[Ohta] 3.Photographic Records of Eruption Products at Unzen Volcano during May 1991-May 1992[Nakada] 4.Photographic Records of People\u27s Life during the Eruption[The Nishinippon] 5.Geological and Tectonic Setting of Unzen Volcano[Okada] 6.The 1990-1992 Eruption of Unzen Volcano[Ohta, Matsuo, Yanagi] 7.Seismological Observations of Unzen Volcano before and during the 1990-1992 Eruption[Shimizu, Umakoshi, Matsuo, Ohta] 8.Surface Temperature Measurements of Lava Domes and Pyroclastic Flows by Infrared Thermal Video System[Umakoshi, Shimizu, Matsuo, Ohta] 9.Seismological Comparison in Eruptive Activity between Mt.Unzen and Mt.Usu[Suzuki] 10.Lava Domes and Pyroclastic Flows of the 1991-1992 Eruption at Unzen Volcano[Nakada] 11.Debris Flows in Mt.Fugen[Hirano, Hashimoto, Moriyama] 12.Geochemical Stuudy of Unzen Volcano by Noble Gas Measurement[Takaoka, Tokunaga, Nagao] 13.Temporal Variation in Specific Gravity of the Lava Extruded from the Jigokuato Crater[Yanagi, Nakada, Maeda] 14.Temporal Variation in Chemical Composition of the Lava Extruded from the Jigokuato Crater, Unzen Volcano[Yanagi, Nakada, Maeda] 15.Batch Franctionation Model for the Evolution of Unzen Volcanic Rocks[Yanagi, Nakada, Maeda] 16.Geological Examination of the Two Old Maps from the Tokugawa Era Concerning the “Shimabara Catastrophe”[Miyachi] 17.Monitoring Ground Movements of Chijiwa Foult and Mt. Mayuyama Using the Global Positioning System for Surevying[Esaki, Aikawa, Okubo, Shimizu, Ohta] 18.Slope Stability of Mt. Mayuyama under the Volcanic Activity of Unzen Volcano[Ochiai, Hayashi, Umemura, Iryo] 19.Earthquake Observations at Mt. Mayuyama[Tsutsumi, Aso, Kitagawa, Uno] 20.Decision Making Process of Both the Administration Bodies and the Inhabitations for Evacuation during the Eruption of Mt. Fugen in Unzen Volcano[Matsunaga, Takahashi] 21.A Documentary of People\u27s Life During the 1990-1992 Eruption of Unzen Volcano[Kawazoe, Okada] References本書は、1990年11月に噴火を開始した雲仙岳の火山活動について地球物理学的、地球科学的、地質学的観測、溶岩組成に基づく噴火モデルおよび眉山崩壊の土質工学的予測を含む総括的報告である

Unzen Volcano : the 1900-1992 eruption

本書は、1990年11月に噴火を開始した雲仙岳の火山活動について地球物理学的、地球科学的、地質学的観測、溶岩組成に基づく噴火モデルおよび眉山崩壊の土質工学的予測を含む総括的報告である。1.Chronological Table 2.Photographic Records of the 1990-1992 Eruptions at Unzen Volcano[Ohta] 3.Photographic Records of Eruption Products at Unzen Volcano during May 1991-May 1992[Nakada] 4.Photographic Records of People's Life during the Eruption[The Nishinippon] 5.Geological and Tectonic Setting of Unzen Volcano[Okada] 6.The 1990-1992 Eruption of Unzen Volcano[Ohta, Matsuo, Yanagi] 7.Seismological Observations of Unzen Volcano before and during the 1990-1992 Eruption[Shimizu, Umakoshi, Matsuo, Ohta] 8.Surface Temperature Measurements of Lava Domes and Pyroclastic Flows by Infrared Thermal Video System[Umakoshi, Shimizu, Matsuo, Ohta] 9.Seismological Comparison in Eruptive Activity between Mt.Unzen and Mt.Usu[Suzuki] 10.Lava Domes and Pyroclastic Flows of the 1991-1992 Eruption at Unzen Volcano[Nakada] 11.Debris Flows in Mt.Fugen[Hirano, Hashimoto, Moriyama] 12.Geochemical Stuudy of Unzen Volcano by Noble Gas Measurement[Takaoka, Tokunaga, Nagao] 13.Temporal Variation in Specific Gravity of the Lava Extruded from the Jigokuato Crater[Yanagi, Nakada, Maeda] 14.Temporal Variation in Chemical Composition of the Lava Extruded from the Jigokuato Crater, Unzen Volcano[Yanagi, Nakada, Maeda] 15.Batch Franctionation Model for the Evolution of Unzen Volcanic Rocks[Yanagi, Nakada, Maeda] 16.Geological Examination of the Two Old Maps from the Tokugawa Era Concerning the “Shimabara Catastrophe”[Miyachi] 17.Monitoring Ground Movements of Chijiwa Foult and Mt. Mayuyama Using the Global Positioning System for Surevying[Esaki, Aikawa, Okubo, Shimizu, Ohta] 18.Slope Stability of Mt. Mayuyama under the Volcanic Activity of Unzen Volcano[Ochiai, Hayashi, Umemura, Iryo] 19.Earthquake Observations at Mt. Mayuyama[Tsutsumi, Aso, Kitagawa, Uno] 20.Decision Making Process of Both the Administration Bodies and the Inhabitations for Evacuation during the Eruption of Mt. Fugen in Unzen Volcano[Matsunaga, Takahashi] 21.A Documentary of People's Life During the 1990-1992 Eruption of Unzen Volcano[Kawazoe, Okada] Reference