Clarification of preparation processes for earthquake (high-speed deformation) based on rock deformation studies

本研究是利用住友重工业株式会社制造的高压高温变形仪进行的实验研究，自2000年3月在广岛大学引进以来，已进行了两年的初步实验，取得了以下成果：1.本研究得到了日本住友重工株式会社的研究资助。为了在试件组件中产生均匀的围压(直径23 mm，高度30 mm)，在其顶部放置铅。然而，铅被挤压到热电偶穿过的洞中，有时会在实验过程中切断它。因此，我们用叶蜡石取代了一部分铅来解决这个问题。我们成功地选择了一种有效的石墨环厚度，用它可以将样品加热到1000℃以上。我们首先尝试利用已知的熔化P-T关系来测量含银样品组件中的围压。然而，由于用作围压介质的氯化钠在相对较低的围压条件下(小于1 Gpa)熔化温度低于银，因此很难控制将温度提高到银的熔点。因此，利用氯化钠的熔融P-T曲线测量了围压。碳化钨围压活塞断裂问题有待进一步试验解决。

This research aided by the Monbukagakushou research grant is an experimental research using a high-pressure and high-temperature deformation apparatus built by Sumitomo Heavy Industries, Ltd. Since we introduced this machine at Hiroshima University in March, 2000, we have been working on preliminary experiments for 2 years, and obtained the following results.1. In order to generate homogeneous confining pressure in the sample assembly (diameter of 23 mm and height of 30 mm), lead is placed on the top of it. However, the lead is squeezed into the hole, where a thermocouple goes through, and sometimes cut it during the experiments. Therefore, we replaced a part of the lead by pyrophyllite to solve the problem.2. We have succeeded to choose an effective thickness of a graphite ring, by which the sample can be heated above 1000 ℃.3. We first tried to measure confining pressure in the sample assembly with silver (Ag) using its well-known melting P-T relation. However, since sodium chloride, which is used for confining pressure medium, melts at lower temperatures than silver under relatively low confining pressure conditions less than 1 GPa, it is hard to control to increase the temperature to the melting point of silver. Therefore, confining pressure has been measured using the melting P-T curve of sodium chloride.4. A problem of breaking of tungsten carbide confining pressure pistons remains to be solved in the future experiments.