54 The N.Z. Journal of Science and Technology. [April 
along the reef. Early in 1906 there wa=s great increase of activity, and 
the lava destroyed the villages of Salago and Saleaula to the west, and it 
also flowed east and overwhelmed the villages of Tapatapu and Maleola. 
The distance from the crater, following the winding and turnings, was about 
thirteen miles, and the sea-front covered was nearly nine miles. “ The 
large, fresh lava-streams soon got crusted over on the surface with 
solidified lava, and the liquid lava continued to flow underneath. Even 
at the crater it seldom flowed over the lip, but generally entered holes and 
tunnels in the sides and flowed underground. The lava-field thus became 
honeycombed with channels of liquid or pasty lava, which occasionally 
came to the surface and flooded it with fresh sheets of lava ; at other 
times the surface frequently floated up and was raised by the intrusion of 
fresh lava underneath, so that what had previously been the course of the 
valley now became the highest part of the field. Mr. Williams thinks, 
that the lava must be in places 400 ft. thick ” (Anderson). 
Where the coast was bordered by a coral reef the lava quickly filled 
up the lagoon and thus extended the coast-line. For a stretch where it 
was previously “ iron-bound ”— i.e., formed of old lava not protected by 
a coral reef, as at Asuisui—the lava flowed directly into deep water, and 
did not materially alter the outline of the coast. The flow into the sea 
continued, with only a day’s intermission, from 1905 until 1910 or 1911. 
An immense amount of lava disappeared in this manner, estimated by 
Friedlander as many cubic kilometres, and four times the volume of that 
forming the visible lava-fields (Sapper, 1911). 
When the discharges into the sea were most active, Anderson states 
that explosions were almost continuous, and the whole was obscured by 
clouds of steam, from which fragments of red-hot lava and showers of 
black sand were seen to fall. This black sand formed beds capping 
the lava. Angenheister in 1909 remarks that the explosions took place 
every five to ten minutes. When the lava was flowing in lesser quantity, 
Anderson notes that explosions were much less noticeable, and the lava 
extended itself into buds and lobes, and cooled in the form of a “ pillow- 
lava.” 
The crater of Matavanu has been described in various stages by Jensen, 
Angenheister, Anderson, Friedlander, and Grevel. As seen by me in 1920, 
it is a broad slag-covered cone, with a steep-walled crater about 250 ft. 
deep, narrowly elliptical in form, and elongated about a quarter of a mile 
from south-south-east to north-north-west.* The northern end of the 
crater is partially fallen in, and the depression is extended in this 
direction by two fallen-in tunnels for another 100 yards or so. Farther 
to the north-east there is another disconnected downbreak, with a tunnel 
showing at the bottom in the northern end. Angenheister noted in 1909 
that the lava passed out through two tunnels to the north and one to the 
south, though there was no flow to the surface in the latter direction. 
The eastern side of the crater is composed of red ash below, grey ash above, 
capped by a 5 ft. layer of lava, which is covered on the outer surface by- 
spatter slag. The western side shows lava-flows with red ash between 
and above them, and the same 5 ft. layer of lava on the top. At the 
northern end lavas come in in wedge-shaped fashion, lying unconformably 
on the ash-beds. Sulphur-fumaroles are still active, both near the bottom 
* Compass bearings being notoriously unreliable in basalt volcanoes, I projected 
the line of the elongation to the sea-coast, and found that it bore about three, miles to- 
the west of Matautu. 
