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Is there a correlation between how many hot springs an area has, and how frequent or severe the area's earthquakes are?

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  • $\begingroup$ It strikes me that the only good answer to this question is a spatial analysis of hot springs and earthquakes. @gansub: I think you're assuming he's making that assumption. $\endgroup$ – kwinkunks Mar 12 '15 at 16:03
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Hot springs usually exist in volcanic regions or in areas where there are extensive (normal) faults. The water circulates through the fault zones (basically damaged zones with high permeability) bringing heat from great depths. However these faults don't have to be active.

Therefore a correlation between location of hot springs and present day seismic activity is not necessary but the faults were indeed active at some point in history.

Edit: @winwaed: I wanted to add that there indeed are faults associated with Hot Springs in AR. I am including a figure of the region borrowed from a NPS publication here. Look carefully at the figure in the lower right where water is flowing upwards through a fault. A lot of people have the misconception that there are no faults in the interior of plates. That is not always true. In fact quite the opposite.

enter image description here

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  • $\begingroup$ Your 2nd paragraph is a good point, there are several intraplate hot springs (with no volcanic hostspot) here in Australia. $\endgroup$ – user889 Mar 11 '15 at 19:37
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Yes, there is a correlation.

In other words: places with hot springs are more likely to experience earthquakes than places without hot springs. The relationship is scale-dependent in time and space (your house might not sit on a hot spring but still get earthquakes).

Ideally I'd dig around and find actual data to quantify this spatial correlation (and I hope someone does!), but for now I will settle for qualitative evidence at the continental scale. I offer a visual correlation between the two datasets in question. First, geothermal springs:

Map of geothermal springs in the US

Now earthquakes:

Map of earthquake hazard in the US

Like any correlation in geoscience, it's not perfect. But, broadly speaking, there is one.

Footnote: Actually, there are at least two correlations. As with fracking for shale gas, well stimulations and other industrial activity in geothermal fields has recently been blamed for induced seismicity in places like the Imperial Valley of southern California. Sometimes correlation does imply causation!

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As a counter to @stali's answer, it is possible to have hot springs without volcanism or normal faulting - although these two scenarios do cover the most well known examples.

Hot Springs, Arkansas exists because of the local geological structures (folding rather than faulting) that bring ground water up to the surface from deep in the Earth relatively quickly.

Also radiogenic rocks (eg. granites) can increase the thermal gradient, making this scenario more likely. Eg. the UK's "hot springs". Okay they're not that hot, but shallow boreholes found 60C water at Buxton (and nicely radioactive); and hot water in a Lafarge mine/quarry in Weardale (?). The last I heard, there were plans to turn the latter into a spa...

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    $\begingroup$ There are hot springs all around the edges of the Great Artesian Basin in the eastern half of Australia. Well, warm springs anyway. They aren't anywhere near volcanism or fault lines. They sound pretty similar to the UK ones. $\endgroup$ – naught101 Mar 12 '15 at 4:10
  • $\begingroup$ @naught101 Earth's crust is pervasively faulted. There are faults in UK, trust me. They just are not tectonically active anymore. $\endgroup$ – stali Mar 12 '15 at 13:52
  • $\begingroup$ @winwaed You do need faults/fractures/fissures so that water from deeper hotter rocks can flow upwards, near the surface. There are faults associated with Hot Springs in AR. I have clarified this in my answer above. $\endgroup$ – stali Mar 12 '15 at 13:54
  • $\begingroup$ Sure the UK might have them (actually a few do still move!) and the tw locations I gave are both Carboniferous - ie. lots of faults; but my understanding was that Hot Springs,AR was due to folded rocks. Permeable and impermeable - the impermeable novaculite layers are quite striking from the air. $\endgroup$ – winwaed Mar 12 '15 at 16:25

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