|
What
is tephra?
|
Volcanic
Rock and Glass Pieces |
|
Mt. St. Helens,Washington |
|
Kilauea Volcano, Hawai`i;
lava fountain |
Photograph by A. Post on
May 18, 1980
|
|
Photograph
by C. Heliker on September 19, 1984 |
Tephra
is a word which is used to describe pieces of volcanic
rock and lava that is blasted into
the air by a volcanic eruption. Tephra comes in
many sizes and can be ash or something up to 3
feet in diameter. (2millimeters – 1 meter)
Bigger pieces of tephra usually fall pretty close
to the volcano, but ash can travel up to hundreds
and thousands of miles away.
It is hard to predict how far away volcanic ash
will fall from the volcano. It depends on the size
of the ash, the amount of ash, which way the wind
is blowing, and how strong the wind is.
When volcanic ash falls into a place it really
disrupts the normal activities that happen. It
is so small, it will get into everything and it
is like sandpaper because it is rough. It can turn
the day so dark it seems like night and can also
make it so you can’t see at all. The ash
is slippery, especially when it is wet and so roads,
highways, and airports may need to close. Since
the ash is small it can get into car and jet engines
and ruin them. Because it is very abrasive, or
rough, it can also ruin things like brakes and
transmissions,
 |
 |
 |
 |
Mount St. Helens
Tephra: block |
Mount St. Helens
Tephra: ash & pumice |
Kilauea
Tephra: reticulite |
Kilauea
Tephra: Pele's hair |
| Photograph by S.R. Brantley |
Photograph by D. Wieprecht |
Photograph by D.A. Swanson |
Photograph by D.A. Swanson |
 |
 |
 |
 |
| Daylight
turns into darkness... |
Roofs may collapse
from added weight... |
Machinery and vehicles
will be damaged |
Farmland will be covered... |
| Photograph by M. Mangan |
Photograph by E. Endo |
Photograph by W.E.Scott |
Photograph by C. Newhall |
 |
 |
 |
 |
| Roads
will be slippery, blocked, or blocked... |
Power systems may
shut down... |
Waste-water systems
may clog... |
Gutters may fill and
collapse... |
| Photograph by R. Hoblitt |
Photograph by W.E. Scott |
Photograph by W.E. Scott |
Photograph by W.E. Scott |
|
