FY 2001

Earthquakes' impact on hydrothermal systems may be far-reaching

Johnson, H.P., R.P. Dziak, C. Fisher, C.G. Fox, and M.J. Pruis

Eos Trans. AGU, 82(21), doi: 10.1029/01EO00127, 233–236 (2001)

Recent work has linked earthquake activity with changes in flow and temperature due to hydrothermal venting at mid-ocean ridges. These intriguing relationships are important motivation for modeling marine hydrothermal systems. However, a re-examination of some earlier vent monitoring data from the Juan de Fuca Ridge, combined with analysis of recently reprocessed SOSUS (SOund Surveillance System) hydrophone data (Figure 1), suggest that such activity may be linked over considerable distances of greater than 200 km and reaction intervals of over a month.

The available observational data are sparse, so the direct association between earthquakes and changes in crustal fluid circulation are difficult to verify. However, the response times and distance scales are consistent with other observations, including earthquakes in land-based settings [Hill et al., 1993] and modeling of flow in porous media [Pruis et al., 2000]. If true, these associations imply that marine hydrothermal systems are extremely complex and may be sensitive to very subtle environmental changes.