| dc.creator |
Kervyn, M. |
|
| dc.creator |
Belton, F. |
|
| dc.creator |
Mbede, Evelyne I. |
|
| dc.creator |
Jacobs, P. |
|
| dc.creator |
Ernst, G.G.J. |
|
| dc.creator |
Harris, A.J.L. |
|
| dc.date |
2016-09-21T14:02:28Z |
|
| dc.date |
2016-09-21T14:02:28Z |
|
| dc.date |
2006-09 |
|
| dc.date.accessioned |
2018-03-27T08:58:23Z |
|
| dc.date.available |
2018-03-27T08:58:23Z |
|
| dc.identifier |
Kervyn de Meerendre, M., Harris, A., Mbede, E., Belton, F., Jacobs, P. and Ernst, G., 2006. MODLEN: A semi-automated algorithm for monitoring small-scale thermal activity at Oldoinyo Lengai Volcano, Tanzania. Quantitative Geology from Multiple Sources. |
|
| dc.identifier |
http://hdl.handle.net/20.500.11810/4006 |
|
| dc.identifier.uri |
http://hdl.handle.net/20.500.11810/4006 |
|
| dc.description |
Active and potentially hazardous volcanoes in East Africa (Tanzania, Kenya,
Ethiopia) are not currently monitored on a regular basis. Among the most active ones,
Oldoinyo Lengai has been almost continuously active since 1983. Activity has been confined
to small-scale effusive and explosive eruptions of low temperature (~550°C) natrocarbonatite
within the summit crater. Historical eruptions’ accounts illustrate that Oldoinyo Lengai also
repeatedly displays much more explosive (i.e. violent strombolian or sub-plinian style)
eruptions of silicate magma. Daily MODIS images offer a low-cost route to monitor volcanic
thermal activity. Existing methods applied on a worldwide scale, such as the MODVOLC
algorithm developed by the University of Hawaii, are insufficiently sensitive to monitor
small-scale thermal anomalies. MODLEN is an adapted semi-automated algorithm, using
MatLab, which allows daily record of the thermal emission at Lengai and the identification of
high intensity activity. MODLEN is calibrated and validated using the activity reports from
field visits. Despite the small-scale and low temperature of the eruptive activity at Lengai,
MODLEN is able to detect all periods of increased activity observed in the field. A 5-year
time-series dataset, resulting from analysis of more than 2500 night-time MODIS scenes, has
been acquired as a baseline for future near-real time monitoring. It provides insights on the
factors controlling the temporal distribution of high intensity activity events. Improvement of
the method, to avoid false detection due to partial cloud coverage and detection of the full
extent of thermal alerts are also discussed. Although recent activity has been moderate at
Lengai, a more intense explosive eruption is overdue. Monitoring is needed to try and
anticipate the transition to more hazardous eruption styles and to gain insights into the
controls on eruption intensity at Lengai. |
|
| dc.language |
en |
|
| dc.subject |
Oldoinyo Lengai |
|
| dc.subject |
Thermal monitoring |
|
| dc.subject |
MODIS |
|
| dc.subject |
MODVOLC |
|
| dc.subject |
MODLEN |
|
| dc.subject |
Eruption intensity |
|
| dc.subject |
Lava ponds |
|
| dc.subject |
Lava fountaining |
|
| dc.subject |
Lava flows |
|
| dc.title |
A Semi-automated Algorithm for Monitoring Small Scale Thermal Activity at Oldoinyo Lengai Volcano, Tanzania |
|
| dc.type |
Journal Article, Peer Reviewed |
|