Heavy Rain Can Trigger Earthquake

New Scientist ^ | 2-25-2008 | Catherine Brahic

[blam]

Heavy rain can trigger earthquakes

13:44 25 February 2008
NewScientist.com news service
Catherine Brahic

The rain-induced tremors occurred in karst landscape. This forms a distinctive topography of soft carbonate rock, such as limestone, riddled with deep channels and caves in which water pressure could build

Huge downpours of rain can trigger earthquakes in landscapes riddled with caves and channels by increasing pressure within underlying rock, suggests a new study.

It was already known that rainfall could cause tremors, but the amount of water needed is much more than previously thought, says Steve Miller, a geologist at the University of Bonn, Germany.

In recent years, geologists have documented small earthquakes that occurred after heavy rainfall in Germany, Switzerland and France. All were low in magnitude – meaning they could be detected by seismographs, but not felt by humans.

Some experts have suggested that although the rainfall was heavy, the fact that rain could trigger an earthquake at all suggests that it takes extremely little to produce a tremor. They concluded that the Earth's crust in a delicate balance, teetering on the edge of a slight shake-up at any moment.

Landscape key

Now, in the new study, Miller disagrees, pointing out that all the three documented events happened in a specific type of landscape known as karst.

Other geologists studying rain-triggered earthquakes did note that they occurred in karst geology, but they did not delve into the possible implications.

Karst landscape features a distinctive topography of soft carbonate rock riddled with deep fissures, underground channels and cave systems (see photo, right).

These characteristic features are carved out when carbonate bedrock – typically limestone or dolomite – is dissolved slowly by the action of slightly acidic rainwater over thousands of years. And these structures, says Miller, are key.

[al baby]

FYI

[SevenofNine]

Then how come in my state California earthquake we had was after heat wave LOL!

[mtbopfuyn]

There’s some really neat limestone formations around Austin, TX and it’s Edwards Aquifer.

[Elpasser]

Next, they’ll report that Global Warming does, too.

[Godzilla]

Then how come in my state California earthquake we had was after heat wave LOL!

Different geologic forces behind the faulting.

[SevenofNine]

Hey Godzilla how come you start earthquakes in Japan LOL!

So blame on the rain also on you RIGHT LOLOLOL!

[cripplecreek]

Global cooling has been causing some local tremors for me. I lay in bed at night and listen to the ice on the lake freezing. Since I’m only about 30 feet from the lake I can feel the mild jolts that are transferred to the frozen ground.

[blam]

"There’s some really neat limestone formations around Austin, TX and it’s Edwards Aquifer."

Yup. Been there. I retired from TI.

[43north]

There is a positive correlation between major earthquakes and the Full Moon (as in major ocean tide movements).

The great Good Friday Alaska Earthquake of 1964 occurred within 6 minutes of the official time of that day’s Full Moon.

The December 26 Indonesian earthquake a couple of years ago also occurred on a Full Moon.

I’m not saying that ALL quakes happen in conjunction with the Full Moon but it sure would be interesteing if a researcher were to pull out an ephemeris and see exactly what the correlation is. I’d bet that it is greater than 50%.

[3Lean]

“the fact that rain could trigger an earthquake at all suggests that it takes extremely little to produce a tremor”

Now why would anyone suggest that only a little rain would cause an earthquake after observing that a huge rainfall could cause a small earthquake??

Oh yeah, so they can get on the “you’re going to die if you don’t fund my research bandwagon” with statements like this...
“They concluded that the Earth’s crust in a delicate balance, teetering on the edge of a slight shake-up at any moment”

[Soliton]

Wow, I hope this was an inexpensive study. This has been known and studied for a long time. Heck old faithful is a benign example of water sinking and turning to steam and then spouting. What would happen if there wasn’t a safe way to blow off the steam?