Operation Test of Artificial Seismic Prospecting around Active Crater in Aso Volcano

阿苏火山活火山口周围人工地震勘探作业试验

• 批准号: 10554018
• 负责人: SUDO Yasuaki
• 金额: $ 0.77万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10554018/
• 关键词: Aso Volcano; Axtive Crater; Subsurface Structure; Arttificial Seismic Prospecting; Velocity Structure; Coda Wave; Volcanic Tremor; 活動火口

The two observation experiment in November and December 1998 had been clarified. a basic structure of the magma system in Aso Volcano.1.Initial Motion Reading : Reading work of initial phases of artificial earthquake was composed by the expert researchers, and selected the most appropriate value individually examining two or more reading values. Because the Naka-Dake crater is now active, and the subsurface structure near the crater especially is showed to be complicate, and the volcanic tremors always occur, and the initial phase amplitude was small, the reading of the initial motion was difficult. As a result, the anomalies of travel time have been recognized near the crater and the reflective waves have been read from the crater to Kusasenri region.2.Refraction Method Analysis : The 2-dimension velocity structure has been analyzed, and have been compared with the traditional model.3.About the reflective plane : The travel times of reflective waves have showed the shape of magma reservoir at the region of 3km in depth of 3km west from the crater. This result is thought to be a reflection wave from the head of the magma reservoir of Aso Volcano, which centers on Kusasenri about 6km depth in the underground of 2-3km in the radius.4.About the Observation of Volcanic Tremors : At this experiment, the volcanic tremors was observed. A lot of volcanic tremors were observed with the deliberate observation stations, which had been developed around the crater. The hypocenter of volcanic tremor has been presumed to be just beneath the crater. The focal mechanism of tremor have been included the element of double couple.5.Reflection Method near the Crater : By the mini-vibrator the western subsurface region of the crater has been analyzed.These results were printed as a report and distributed.

1998年11月和12月的两次观测实验已经澄清。阿索火山岩浆系统的基本结构。1.初始运动阅读：人工地震初始阶段的阅读工作由专家研究人员组成，并选择最合适的值，分别检查两个或多个阅读值。由于中岳火山口现今处于活动状态，特别是火山口附近的地下结构复杂，火山地震时有发生，且初相振幅较小，给初动的阅读带来困难。2.折射法分析：分析了二维速度结构，并与传统模型进行了比较。3.关于反射面：反射波的走时显示了火山口以西3 km处3 km深处岩浆库的形状。这一结果被认为是来自阿索火山岩浆库顶部的反射波，该岩浆库中心位于库萨千里地下约6 km处，半径为2- 3 km。4.关于火山震动的观测：本次实验观测到了火山震动。在火山口周围建立了专门的观测站，观测到了大量的火山震动。据推测，火山震动的震源就在火山口下方。地震的震源机制已包括双力偶元素。5.火山口附近的反射法：通过小型振动器分析了火山口西部的地下区域。这些结果作为报告打印并分发。

项目成果

須藤 靖明 他: "活動火口におけるマグマ熱水系構造探査法の実用化実験研究成果報告書"106 (2000)

Yasuaki Sudo等：《活动火山口岩浆-热液系统结构探测方法实用实验研究报告》106（2000）