We get a lot of news about direct "feedbacks" from global warming.
This series is about indirect impacts that anthropogenic global warming has engendered (Global Warming & Volcanic Eruptions).
Seeking the full picture of indirect impacts, I have wondered for quite a while about how a graph would look if I used each and every PSMSL tide gauge station (all 1,465 of them) and did a mean average sea level change on the data (more on that later).
Global pressure on the crust of the Earth is one indirect impact of global warming, as rising tides and subsequent oscillating bottom pressures caused by melt water follow:
(Is A New Age Of Pressure Upon Us?, May 2010). So, in today's episode I will combine some of all of that into a hypothesis.
"In this post we are not considering the pressures of 21st Century life, with its myriad social stresses and concerns.
A recent post at Ecocosmology Blog indicated that scientists have studied the varying effects and pressures of ocean levels on the crust of the Earth."
The hypothesis is that earthquakes have increased as ice sheet and glacial melt has led to the redistribution of cryosphere mass into the oceans.
That mass is relocated widely over the Earth's crust.
Thus, it could be related to the increase of earthquake events as explained in more detail below.
II. Telltale Graphs
|Fig. 3 Same trend as sea level|
What makes the last ~85 years look steep in those two graphs is the fact that there was a lot of sea level fall during the first part of the PSMSL recorded time-frame (1807 - 1856).
Greenland was melting back then, releasing regular melt water as well as releasing the illusive ghost water too (Proof of Concept - 3, 5; The Ghost-Water Constant, 2, 3, 4, 5, 6, 7).
As a result, those northern hemisphere drops in sea level were predominant until other sources (Antarctica & land glaciers) began to contribute melt water too.
|Fig. 4 [Zone, # of quakes]|
That earthquake data contained, among other things, the latitude and longitude of the epicenter of the quakes, so I was able to link the quakes to particular WOD Zones (e.g. Fig. 4).
The earthquake data in the graph at Fig. 3 indicates a constant increase trend in earthquake activity around the globe (see trend line @ Fig. 3).
|Fig. 5 Same trend as earthquakes|
It stands to reason that ongoing release of downward pressure on land mass as ice sheets melt, and the subsequent increase of downward pressure in other areas as the melt water and ghost-water are relocated to other ocean areas, changes the pressures placed on the Earth's crust.
Those increases and decreases in pressure can become triggers for earthquake activity in areas where just a little more or just a little less can break things loose (as in the case of fracking).
IMO, these observations that are being set forth in today's post give us sufficient accord so that we can put our lab coats on and proceed to the next task.
The next task is to falsify or verify the evolving hypothesis with more data, observations, and analysis.
If you are interested in this developing hypothesis, here is a list of the posts that have been previously published on this subject (Is A New Age Of Pressure Upon Us?, 2, 3, 4, 5, 6, 7, 8).
UPDATE: It dawned on me that Zones 7300, 1400, 1401, 1402, 1300, 1301, 1302, 1303 should be the first group for consideration (Fig. 6).
That means leaving out Zones 7109, 5107, 1304, 1305, 1307, 1313, and 1012 from (Fig. 5) because they are not in the same geographical area.
The reason is that the Zones being removed from consideration at this time, are not grouped properly geographically (they can be considered later).
Thus, the focus is on the Mediterranean Sea area (Fig. 6).
We have some specific papers and news to work with for that area (Mediterranean Faults, cf. Jerusalem Post).
The next post in this series is here, the previous post in this series is here.
Bill McGuire (University College London):