Alarm system of Debris flows by monitoring Ground tremor

在日本樱岛火山野尻河用一种新的地震传感器系统观测了泥石流。一般来说，远离山谷，泥石流引起的地震动会变小，这种现象似乎与火山活动不同。为了考察泥石流现象，我们在校园内进行了室外实验，模拟了活火山中泥石流的涌动。在室外实验中观测到的地震动频谱与在活火山泥石流中观测到的频谱非常相似。我们证实，放电的强度有与地面震动大小成正比的趋势。我们可以发现，观测到的地震动频率可以区分泥石流和清水流。泥石流的频率范围为50 ~ 100 Hz，泥石流的频率范围小于50 Hz。我们的火山泥石流探测触发系统可用于探测滑坡、雪崩等灾害的发生。

Debris flows were observed by using a new system of ground tremor sensor in the Nojiri River of Mt. Sakurajima, Volcano, Japan. In general, going away from valley, ground tremor by debris flow will become small and this phenomenon seems to be different from volcanic activity. To examine the phenomenon of debris flow, we carried out the outdoor experiments in the campus, and replicated the surging out of debris in an active volcano. The spectrum of ground tremor observed in the outdoor experiments is very similar to the spectrum observed in debris flows in the active volcano. We confirmed that the magnitude of discharge has a tendency to be in proportion to the size of ground tremor.We could find that observed frequency of ground tremor distinguishes between debris flow from clear water flow. The value of frequency is from 50 Hz to 100 Hz for debris flow and less than 50 Hz for clear flow. Out trigger system of detecting the volcanic debris flow is available to detect the occurrence of land-slide, snow avalanche and so on.