VALENTINE GEYSER—Located at the base of a large pear-shaped alcove,
Valentine is a typical cone type geyser that first erupted on
Valentine’s Day, 1907. Its activity has varied considerably—being
dormant some seasons, erratic during others, yet showing a high degree
of regularity at times. During the past several seasons, it has erupted
from a minimum of once every two days to a maximum of once a day. An
eruption lasts 5-7 minutes and reaches a height of 20-50 feet (6-15 m.)
above the seven foot cone. The eruption is followed by a steam phase
lasting an hour.
LEDGE GEYSER—The largest geyser in the Porcelain Basin, changed
dramatically after an earthquake that occurred June 30, 1975. In 1974 it
had been erupting about twice a day, but after the quake Ledge was
dormant for nearly two years. Then during the summer of 1977 it had but
two eruptions. Check the prediction board at the museum to see if Ledge
Geyser is active this year.
AFRICA GEYSER—named for the spring that preceded it which was roughly
the shape of the continent. The spring became a geyser in February of
1971. At first it was intermittent but as time passed the periods
between eruptions grew shorter until it became a constant geyser. In
1977 it was always powerful—sometimes emitting a mixture of steam and
water; other times just steam.
THE WHIRLIGIGS AND CONSTANT GEYSERS—these three features seem to be
interconnected. Constant Geyser, dormant for several years, reactivated
in the early ’70’s and now erupts up to 30 feet (9 m.) once or twice an
hour; often prior to an eruption of one of the Whirligigs. In recent
years, Big and Little Whirligig have traded active periods. When one is
more active, the other is less. Watch for the 15 foot (4 m.) angled
plume from Little Whirligig’s orange vent or listen to the distinctive
chugging produced during Big Whirligig’s splashing eruption. As with
many geysers, the water level rises in these pools prior to an eruption.
EBONY AND BEAR DEN GEYSERS—are another set of related features. In the
’60’s Bear Den Geyser first appeared and as it increased in activity,
Ebony Geyser became dormant. Today Bear Den Geyser erupts in bursts,
arcing up to 40 feet (12 m.) from the den-like vent, four to six times
daily. The death of Ebony Geyser may have been hastened by objects
thrown into its vent by thoughtless visitors. This debris is cemented
into place by the silica deposited from the water, choking off the vent.
Minute Geyser in the Back Basin may have suffered a similar fate.