1. Glenn Spinelli and Demian Saffer
Trench-parallel fluid flow in the Nicoya margin subduction zone resulting from temperature differences
Glenn Spinelli and Demian Saffer

2. Subduction zone hydrogeology
Saffer and Bekins, 1998
fluid pressure affects fault strength
transport of chemical species
nutrients to vent communities
heat transport

3. Subduction zone fluid flow in 3-D
Screaton and Ge, 1998
Bangs et al., 1996

4. Thermal controls on hydraulic conductivity
Kato et al., 2004
Morrow et al., 2001
Khot > Kcold
Kcold > Khot

5. Nicoya margin heat flow and temperature
Spinelli et al., 2006
Fisher et al., 2003

6. Along-strike differences in hydraulic conductivity

7. Nicoya margin trench-parallel fluid flow

8. Nicoya and other circum-Pacific examples

9. Conclusions
Along-strike differences in temperature influence subduction zone hydrogeology
trench-parallel differences in fluid pressure & flow
shallow, cold decollement  flow from cold to hot side
deep, hot decollement  flow from hot to cold side

10. Along-strike differences in hydraulic conductivity

11. Effect of dewatering distribution