|Volcano Number: 0403-04=
Last Known Eruption: 2009
Summit Elevation: 149 m
Latitude: 20.57°S 20°34'0"S
Longitude: 175.38°W 175°23"W
Last Known Eruption: 2009
The small islands of Hunga Tonga and Hunga Ha'apai cap a large seamount
located about 30 km SSE of Falcon Island.
The two linear andesitic islands are about 2 km long and represent the
western and northern remnants of the rim of a largely submarine caldera
lying east and south of the islands. Hunga Tonga and Hunga Ha'apai reach
an elevation of only 149 m
and 128 m above sea level, respectively, and display inward-facing sea
cliffs with lava and tephra layers dipping gently
away from the submarine caldera. A rocky shoal 3.2 km SE of Hunga Ha'apai
and 3 km south of Hunga Tonga marks the
most prominent historically active vent. Several submarine eruptions
have occurred at Hunga Tonga-Hunga Ha'apai since
the first historical eruption in 1912.
small islands of Hunga Tonga (upper left) and Hunga Ha'apai (left)
cap a large
seamount located about 30 km SSE of Falcon Island. The two linear
andesitic islands are
about 2 km long. They have inward-facing cliffs that represent
the western and northern
remnants of a the rim of a largely submarine caldera lying east
and south of the islands.
A rocky shoal is visible 3.2 km SE of Hunga Ha'apai and 3 km south
of Hunga Tonga and
marks the most prominent historically active vent.
by Tonga Ministry of Lands, Survey, and Natural Resources, 1991
(published in Taylor and Ewart, 1997)./GVN
Fishermen reported the beginning of an eruption E of Hunga Ha'apai Island
on 1 June at 0800. They noted the ejection of
"fire," tephra, and large volumes of dense white smoke/steam.
Sea water nearby was warm. The next day, there was an
active eruption at the S edge of a shoal. Vigorous steam emission was
occasionally punctuated by ejection of solid material. On 3 June at
0915, the eruption was continuing in shallow water ~1 km SSE of Hunga
Ha'apai. Lava had apparently been erupted from three sources in a SW-NE
trend extending 100-200 m, with current activity at the SW end. There
was no evidence of a new island.
A new eruption from multiple vents on and near Hunga Ha'apai Island
began producing ash and steam plumes sometime
in the late afternoon of 17 March 2009.
aerial photograph of the Hunga Ha'apai eruption at 1804 on 17
Horizontal plumes on the ocean, tephra fallout, and discolored
water can be seen.
Courtesy of Steven Gates/GVN.
of a steam-and-ash plume rising from Hunga Ha'apai Island and
a submarine vent to the S erupting black tephra. View is looking
NW on 18 March 2009.
from unknown photographer on the
Sloban boat provided by Dana Stephenson/Getty Images on boston.com./GVN
of March 16th. The island is located a day's travel by boat from Tonga's
but the clouds of smoke, steam and ash it is sending up to 100 metres
into the air,
means it is clearly visible from the capital.
There are some uncertainty about the dates here
On 19 March flights were disrupted and rerouted around the activity
following warnings from Airways New Zealand and
MetService NZ. An aviation notice on 18 March based on ground observations
from the Tongatapu airport of a plume
rising to an altitude of 7.6 km at 0659 that morning; ash was not seen
in satellite data. Later that day, at 1330,
a plume seen on MODIS satellite imagery was within 1 km of the vent
and moving NE. A similar plume was reported
based on MODIS and ground observations to an altitude of 4.5 km at 1600.
Airport observers continued to report a plume
to 5 km altitude at 1000 on 19 March, and to 4 km at 1700, but with
a band of ash extending 2.5 km NE from the
volcano to 2.4 km altitude.
A new eruptive episode was reported by Tongatapu airport at 1409 on
21 March that sent an ash plume 800 m high.
photo showing the vegetated islands of Hunga Ha'apai
before the eruption.
Courtesy of Brad Scott, GNS Science.
The eruption from Hunga Tonga-Hunga Ha'apai that began from multiple
vents at Hunga Ha'apai island on 17
March 2009 ended after five days of activity on 21 March. The eruption
destroyed all vegetation on the island, one of two high points on a
submarine caldera rim.