As early as 1830, people traveled
to the warm springs between,
Landisburg and Shermans Dale to "take
the cure." They bathed in the water,
and they drank it. It was reported to
be "good as a purgative. Powerful as a
diuretic, helpful for rheumatism,
kidney, and liver complaints,
dyspepsia, eczema, sore eyes, and
general weakness of the constitution."
Today people come to enjoy the waters
at the Warm Springs Lodge restored by
Dorcas and Lloyd Hetrick.
Thirteen miles north of Carlisle,
these were the only known warm springs
in the state until three Peen State
scientists found another nearby.
Barry Weinman, then a Penn State
masters-degree candidate, and his
thesis advisors, Shelton S. Alexander
and Peter M. Lavin, weren't interested
in opening health spas. They wanted to
know if earth-orbiting satellite
photos and other data from NASA sky
eyes would see the springs and their
heat source. If so perhaps there were
clues that would point to hidden heat
sources elsewhere in Pennsylvania
suitable for geothermal power
stations.
LANDSAT-1 {540 MILES HIGH} images
didn't have enough resolution to
locate the springs, SKYLAB photographs
and images taken from 220 miles high
gave better resolution, sufficient to
reveal the springs on enlargements.
To define the thermal extent of the
springs and to locate any new thermal
activity, the scientists asked HRB-Singer,
a State College firm, to make an
infrared reconnaissance flight. The
optical scanner carried by the plane
took an infrared image on April 5
1975, that clearly revealed the
original springs, a new warm spring
about 250 yards southwest, and a
"false" warm spring roughly
three-quarters of a mile to the
northeast. On this image, the three
water sources are strung out on a
straight line like beads on a wire.
The false spring appearing warm on
the infrared film was actually a cold
water source emptying into a nearby
pond that was heated by the sun. The
infrared correctly showed this as a
thermal warm area, but the origin of
the heat was not an underground
source, as was true of the others.
Geochemical analyses indicated that
the water remained underground several
years before pouring out of the warm
springs, was not exposed to high
temperatures for long periods of time,
came from 10,000- to 12,000 foot
depths, and was heated by natural heat
flow from the earth's interior. Water
intrusion into buried hot dry rock or
radioactive decay heating associated
with more deeply buried rock was ruled
out by these results.
The scientists believe warms
springs water mixes with colder
groundwater to keep temperatures in a
63 degrees to 69 degrees F ranger
year-round. A brochure from the Warm
Springs Lodge claims temperatures
remain constant at 66 degrees F.
Either measurement is indicative of
water 10 degrees to 12 degrees warmer
than the mean annual temperature for
neighboring water.
Other field work leads to the
conclusion that the water comes from a
high elevation recharge area to the
east. A cross-sectional drawing shows
a long inclined section of sedimentary
strata trending downward (beyond
Pisgah Ridge) and bottoming out at a
depth of 10,000 to 12,000 feet about a
mile south of the warm springs and
then abruptly turning upward from
underground toward the springs.
Permeable layers in this section
channel water to those depths where it
is heated.
Weinman and Alexander note that two
prominent lineaments intersect north
of the springs, close enough to be a
probable conduit for rapid flow to the
surface. They say the water must come
quickly to the surface, or it would
cool to normal groundwater
temperatures. Vertical planes (faults)
or upward flow in unfractured
permeable beds of sandstone are ruled
out.
Dr. Alexander states that eastern
warm spring systems are geologically
quite different from geothermal areas
in the west that consist of hot water
or steam (Old Faithful-type) sources.
These are often located in recently
active volcanic areas of "dry hot
rock" reservoirs.
A two-well dry rock geothermal
technique to tap such heat sources is
being studied by two colleagues, C.
Wayne Burham and Hubert Barnes. The
wells are drilled into dry hot rock,
the surrounding rock fractured, and
water pumped down one well, heated by
the rock, and pumped up the second
well in the form of hot water or steam
for electricity generation. This is
not a viable technique for eastern
warm springs locales. Thermal warm
springs geology in the east is very
different.
A conclusion of the work is:
"Observation of SKYLAB photos revealed
important spatial relationships
between the warm springs and
lineaments in the region and provided
a vital scale of coverage. Combined
use of LANDSAT imagery, SKYLAB data,
and the underflights offers the best
chance of relating geologic structures
to thermal anomalies."
This project was one of many
designed to see what can be learned
from the wealth of satellite data that
has been acquired in the past several
years by Penn State's Office of Remote
Sensing of Earth's Resources.
Alexander and colleagues in the
geosciences department, Richard R.
Parizek and David P. Gold, are working
with other University scientists to
apply remote sensing research to
practical natural resources problems
in Pennsylvania and elsewhere. Most of
the financial support is furnished by
NASA grants and contracts
