Diary of a volcano...

Ruapehu Bulletin, Volume 13, Issue 611, 7 November 1995, Page 6

Diary of a volcano...

Tuesday 31 October During the last 24 hours significant tremor has continued to be recorded by the Dome Seismograph at Ruapehu. The activity has typically occurred as numerous tremor bursts of 0.5-2 minutes duration. Seismic activity is similar to that of Monday when nearcontinuous voluminous gas emission was occurring from the northern vent, accompanied by intermittent small ash eruptions, apparently from the southern vent. The gas plume was being blown down the eastern slopes of the mountain, with light ash fall in the Whangaehu valley. Aircraft reported a volcanic plume near Lake Waikaremoana at 16,000 to 30,000ft at about 8am today. DoC Turangi staff (Dr Harry Keys) report that a significant secondary lahar appears to have occurred in the Mangatoetoenui Stream, probably on Saturday 28 October. Deposits from a mudflow up to one metre above normal stream flow have been recognised just upstream from the Desert Road bridge. Wednesday 1 November During the last 24 hours significant volcanic tremor has continued to be recorded by the Dome seismograph at Ruapehu. An 8-minute long period of strong tremor (high frequency) was also recorded on the Whakapapa seismograph shortly after 1am this morning. Tremor levels declined after about 5am this morning and have remained at relatively low levels during today. Thursday 2 November During the last 24 hours significant volcanic tremor has continued to be recorded by the Dome seismograph at Ruapehu. This level of seismic activity confirms that the eruption of Mt Ruapehu is continuing. Due to secondary lahars which will play a major role over the next few weeks as the summer melt progresses. Discolouration of waterways flowing from Mt Ruapehu are going to be an on-going feature this summer. Friday 3 November No report received. Saturday 4 November Activity on the volcano is continuing at a modest level. During the last 24 hours volcanic tremor has continued to be recorded at fluctuating, relatively low levels by the Dome seismograph. As in the last few days, the average intensity of seismic activity remains at levels which are relatively high by comparison to pre-eruption levels. Sunday 5 November Activity on the volcano is continuing at a modest level. During the last 24 hours volcanic tremor has continued to be recorded at fluctuating, but relatively low levels by the Dome and Chateau seismographs. . At the time of printing, no report for Monday 6 November had been received.