The rising number of earthquakes in America, not Iceland

This is just a short post drawing attention to a couple of things that are starting to look a little odd. The first was the subject of a post over at Chiefio’s website pointing out that there has been a recent doubling in the number of earthquakes per day along the Western coast. This led him onto a piece that suggests that the recent activity might be a pre-cursor to a volcanic eruption near Hawthorne, Nevada – since there have been over 500 of these quakes in that area. And if one goes to the USGS site that maps their location and strength, the latest image shows that activity is still ongoing.

Recent earthquakes in the Hawthorne area (USGS )

The concentration of activity around a fixed point argues more for volcanic activity than it does a growing risk of a major earthquake. However if one looks at the region in general there is also a lot of activity along the major fault lines through California. However that tends not to be as focused, suggesting that the normal movement along the faults is continuing, though intensified just south of the border.

Recent Earthquakes on the west coast (USGS)

The two phenomena may well be separate. Generally I look for a lack of earthquake activity along a fault line as an indicator that the fault is not moving in that region, and thus stress is building up, and a larger quake will be required at some time in the future to relieve that greater stress. And in that regard it is the zone without the current quakes along the fault path that is more worrying to me than the zones where there is a lot of quaking, and thus movement.

In contrast it is the focusing of lots of earthquakes in a small area that suggests that the cause of the quakes might be more due to volcanic activity. Though one really also needs the relative vertical location of the epi-centers to determine whether magma is moving towards the surface, which is generally a warning of something in the offing.

The other thing that has me a little puzzled is the opposite situation. I have been monitoring the quakes in Iceland since the eruption last year, as reported by the Icelandic Met Office, and recording all those quakes that exceed magnitude 3. (At the bottom of this post. I note that after seeing about a hundred quakes in the past year, there hasn’t been one (greater than 3) since March 12th. Which is kinda odd.

The combination of the two events may or may not be related, we will have to see how things progress, but it is worth taking note of and keeping a closer watch to see what happens next.