I bought a toy on impulse, the other day. It is a digital
water conductivity meter, set up as a total dissolved
solids meter. Temperature compensated, sample and hold.
Auto off. 1000 hr cells.About $16 from HM Digital, LA.
(It turns out that there is a reasonable relation between
the salt load found in the usual run of waters from lakes and
rivers and their conductivities. This is in the order
of TDS mg/L = 0.67 uS/cm., that is, total dissolved
solids in parts per million can be expressed as conductivity
expressed in microsiemens per centimeter scaled by a
two thirds factor.)
I checked that a sample of distilled water read 0 ppm and a
sample from the home faucet read 650 ppm.
It is not encouraging that a leaflet mentions that an EPA
high limit on TDS is set at 500 mg/L.
Later, I browsed for context. I ran across this abstract, and
because it reads a little near the edge of the respectable
AND mentions Earth tides, I thought you might enjoy it.
Here it is.
MODELLING GROUND WATER CONDUCTIVITY ANOMALIES
INDUCED BY DISTANT EARTHQUAKES
WANG, Rongjiang, WOITH, Heiko, MILKEREIT, Claus, and
ZSCHAU, Jochen,
Earthquakes and Volcanism,
GeoForschungsZentrum Potsdam,
Telegrafenberg,
Potsdam, 14473, Germany,
tide@gfz-potsdam.de
In the analysis of the multiparameter data monitored since more
than 4 years [ago] at an artesian well in Kajaran, Armenia, we found
that the specific electrical conductivity of the well water
respon[ded] significantly to distant moderate- and major-scale
earthquakes. The sensitivity of the system was shown again by
the anomalies induced by the Izmit earthquake, August 17, 1999,
whose epicenter was at a distance of 1400 km. Both co- and
post-seismic conductivity anomalies are uniformly of negative
sign and satisfy a power-law attenuation with the epicenter
distance. The post-seismic curve is relatively well characterized
and reproducible. In particular, the conductivity parameter is
more sensitive to earthquakes than the water discharge which
[has been] monitored since September 1998, too. In the conductivity
parameter the maximum earthquake-induced offset is hundreds
to thousands times larger than the amplitude of earth tides,
and in the water discharge such signal ratio is several tens.
The quasi-static strain of all observed earthquakes has been
estimated to be limited by 10^(-9) which is at least one order
lower than the tidal strain. It is therefore difficult to explain
the phenomena with the poroelastic response of the hydrological
system. We propose the degassing of oversaturated ground water
triggered by seismic waves as a reasonable mechanism.
Using a simple model, we give a preliminary quantitative explanation
of the observed hydrological changes induced by distant
earthquakes.
Earth System Processes - Global Meeting (June 24-28, 2001)
Edinburgh International Conference Centre: Poster area
4:30 PM-6:00 PM, Monday, June 25, 2001