Water-, mud-, gas-, and petroleum-bearing seeps are part of the Salton
Sea geothermal system (SSGS) in southern California. Carbon dioxide is
the main component behind the seeps in the Davis-Schrimpf seep field
(similar to 20,000 m(2)). In order to understand the mechanisms driving
the system, we have investigated the seep dynamics of the field by
monitoring the temperature of two pools and two gryphons for 2180 h
(90.8 days) in the period from December 2006 to March 2007, with a total
of 32,700 measurements per station. The time series have been analyzed
by statistical methods using cross correlation, autocorrelation and
spectral analysis, and autoregressive modeling. The water-rich pools
never exceed 34.0 degrees C and are characterized by low-amplitude
temperature variations controlled by the diurnal cycles in air
temperature. The long-term validity of these results is evident from a
second period of temperature monitoring of one of the pools from
December 2007 to April 2008 (120 days). In contrast to the pools, the
mud- rich gryphons have a strikingly different behavior. The gryphons
are hotter (maximum 69.7 degrees C) and have large amplitude variations
(standard deviation of 6.4) that overprint any signal from external
diurnal forcing. Autoregressive modeling shows the presence of distinct
hot and cold pulses in the gryphon temperature time series, with
amplitudes up to 3 degrees C. These pulses likely reflect a combination
of hydrothermal flux variations from the SSGS and the local temporal
changes in bubbling activity within the gryphons.