New Zealand Journal of Geology & Geophysics abstracts
Potential impacts of a widespread subplinian andesitic
eruption from Tongariro volcano, based on a study of the Poutu Lapilli
D. W. Hitchcock
J. W. Cole
Department of Geological Sciences
University of Canterbury
Private Bag 4800
Christchurch
8140, New Zealand
Abstract Recent
eruptions from Tongariro volcano, particularly from
Ngauruhoe, have been small (Volcanic Explosivity Index or VEI ≤ 3), but
between
11 000 and12 000 cal. yr BP there was a series of larger subplinian
eruptions (VEI
4) from Tongariro volcano (Mangamate Formation), the last of which
formed the
Poutu Lapilli. This unit is considered to have had a volume of 1.1 km3,
distributed in three main lobes (NW, NE, E) around a possible source or
sources
close to the present site of Ngauruhoe. Column height during the
eruption
ranged from 16 to 23 km. If such an eruption occurred today it would
have a
significant impact on the surrounding area. In the proximal zone
(<25 km
from the source) >20 cm of ash/lapilli would be deposited,
sufficient to
cause collapse of some buildings in Tokaanu and the surrounding
communities and
damage to the Tokaanu Power Station. Much of the other infrastructure
in the
area (e.g., electricity transmission lines, water supply and
distribution, roads)
would also be affected, as would the tourist industry. Evacuation may
be
necessary from this proximal area, and plans for this should be drawn
up well
before the event. Adequate provision also has to be made for disposal
of ash
from towns/communities and from key roads. Medial and distal areas (up
to 100
km from the source) would be affected, but to a decreasing extent with
distance
from the source. An eruption such as that which the Poutu Lapilli is
possible
at any time in the future from Tongariro, and an effective management
system
must be established to deal with such an event.
Keywords volcanic hazards;
infrastructure; subplinian eruption;
Poutu Lapilli; Tongariro
G05052; Online publication date 4 April 2007;
Received 31 October 2005;
accepted 6 March 2007
New Zealand
Journal of Geology & Geophysics, 2007, Vol. 50: 53–66
0028–8306/07/5002–0053 © The Royal Society of
New Zealand
2007
PDF file of entire paper: Print-quality
(4187K) | screen-quality (3446K)
This year's abstracts |
Journal home page |
All abstracts |
Publishing home page
