| Popis: |
INTRODUCTION Lahars from Mt. Ruapehu's Crater Lake pose the greatest volcanic risk to mountain users. Recent large eruptions occurred in 1945, 1969, 1975, 1981, 1988, and 1995-96, and all generated lahars (Gregg, 1960; Houghton et al., 1987). There are three ski fields on the upper slopes of Mt. Ruapehu (Figure 1), and lahars originating from the summit crater lake, which travel at speeds of up to 20 m/s, can reach the upper ski fields within 90 seconds (Ruapehu Surveillance Group, 1996). In addition, the summit area is a popular destination for hikers and climbers. Anyone caught in the path of a lahar is likely to be injured or killed. Consequently, it is of utmost importance to detect eruptions that are likely to generate lahars and to trigger warning systems on the mountain in near real-time. In contrast, the risk of injury from the eruption of large rocks is confined to... |
