Several interesting results of research conducted by Josh Gordon and Fred Belton, with support from Warner Cribb and Jim Henry of the MTSU Geosciences Department, are explained below.

1. We made a continuous reading of barometric pressure with a barograph at Lengai's south crater for a month-long period during June-July 2004.  We learned that more eruptions began or increased in intensity during falling or minimal barometric pressure than during increasing or maximal barometric pressure. Analysis of the data by a Wilcoxon signed rank test gave 99% confidence that this difference is significant.  However, with only a 30 day observation period, it is clear that much more data is needed to support  these  findings.

2. We tabulated observations of Lengai for over 400 days back to 1987.  For each date we determined the number of days to the nearest lunar perigee, apogee, full moon, and new moon. For each category we constructed a graph showing the percentage of days that activity was observed. For example, we looked at every recorded visit to Lengai on dates that occurred 2 days before a lunar perigee, and calculated the percentage of those days that Lengai was erupting.

The two graphs showing active days before and after new and full moons did not show any obvious trends, but the two graphs showing active days before and after the lunar perigee and apogee showed a distinctive pattern of increased activity near the perigee and decreased activity near the apogee.  This is particularly apparent when one compares the percentage of active days within 5 days of perigee and 5 days of apogee.  We are working on statistics that will demonstrate the significance of this difference.  The perigee and apogee graphs are shown below.