Geology Reference
In-Depth Information
Figure 1.8
The geophysical cape in action. Electronics and observer are
both dry, with only the sensor bottle exposed to the elements. The observer
can retreat still further, to view the display.
1.4.4 Geophysics in the rain
Geophysicists huddled over their instruments are sitting targets for rain, hail,
snow and dust, as well as mosquitoes, snakes and dogs. Their most useful
piece of field clothing is often a large waterproof cape, which they can not
only wrap around themselves but into which they can retreat, along with
their instruments, to continue work (Figure 1.8).
Electrical methods that rely on direct or close contact with the ground
generally do not work in the rain, and heavy rain can be a source of seismic
noise. Other types of survey can continue, since most geophysical instru-
ments are supposed to be waterproof and some actually are. However, unless
dry weather can be guaranteed, field crews should be plentifully supplied
with plastic bags and sheeting to protect instruments, and paper towels for
drying them. Large transparent plastic bags can often be used to enclose
instruments completely while they are being used, but even then condensa-
tion may create new conductive paths, leading to drift and erratic behaviour.
