[Image,200K,GIF]
View southeast of Augustine volcano, Alaska. At the
beginning of an eruption about 350 years ago the former
summit collapsed as a huge debris avalanche. The avalanche
swept to the sea, forming the hummocky deposit visible in
foreground. The great avalanche apparently initiated a
gigantic local tsunami that ravaged the shores of lower
Cook Inlet.
[Image,310K,GIF]
Vertical aerial view of north part of Augustine Island in
September 1991. At the beginning of the 1883 eruption a
large debris avalanche suddenly removed the volcano's
summit (just south of image) and slid to the sea, forming
the hummocky deposit on the coast. Light-colored materials
overlying the hummocky debris avalanche are deposits of
numerous hot (so-called "pyroclastic) flows from the dome
during eruptions in 1883, 1976, and 1986.
[Image,240K,GIF]
Aerial oblique view east-northeast of Homer Spit, jutting
4 miles out into Kachemak bay in southern Cook Inlet.
Thousands of people flock to the spit daily in summer. The
highest part of the spit is only a few feet above high-
tide limit. The spit is thus vulnerable to a tsunami from
a future debris avalanche originating at Augustine volcano
70 miles away.
[Image,290K,GIF]
View south of Augustine volcano. During the Winter-Spring
1986 eruption, hot pyroclastic flows melted snowpack and
caused small catastrophic floods that carried these large
boulders to the lower volcano flank and the sea.
[Image,170K,GIF]
View south of Mt. Augustine volcano, Alaska, in July 1990.
The low, hummocky, vegetated debris in right foreground is
the deposit of a great landslide (debris avalanche) at
beginning of the 1883 eruption that removed the summit.
After the avalanche five dome-building eruptions (1883,
1935, 1963-64, 1976, 1986) restored the summit ot its
former volume and steepness, setting the stage for a new
avalanche.
