[Rockhounds] Mauna Loa may cause a tsunami?

[Kitty & Bill Heacox]

Hi List,

[We've had computer problems, so I've been away for a while.]

Bill found the following in a weekly science magazine he subscribes to, 
and thought it might interest you all. I found the abstract for the 
paper that appeared in /Nature,/ and copied it below the /Science News/ 
article (I couldn't get the whole article without subscribing).

Enjoy, and don't get nightmares if you live near the ocean. ;-)

Aloha, Kitty


 From /Science News/, Feb. 2, 2008:

EARTH SCIENCES: *_A crack and a fault in paradise:_*

Mauna Loa, Hawaii’s most massive volcano, may be splitting open the 
Earth’s crust. A team of French geologists reached that conclusion after 
pinpointing the location of more than 1000 miniature earthquakes that 
happened beneath Mauna Loa and its little sister volcano, Kilauea, 
between 1988 and 1999. Some of the earthquakes under Kilauea occurred at 
depths well below the ocean crust, suggesting a fault there. A computer 
model indicates that Mauna Loa’s heft was enough to bust open the crust 
and create that fault, says geophysicist Jean-Luc Got, of the University 
of Savoy in France, who led the study.

Including Mauna Loa’s underwater portion and a depression it made in the 
seafloor, the volcano is more than 17,000 meters tall, nearly double the 
height of Mount Everest.

The apparent crack, which has not been directly detected, could cause an 
enormous tsunami if the rock beneath the volcanoes slides up against a 
step in the ocean crust, Got says. His team speculates that such an 
event may have spurred an 1868 tsunami and landslide that killed dozens. 
The study appears in the Jan.24 issue of /Nature/.

/Nature/ *451*, 453-456 (24 January 2008) | doi:10.1038/nature06481; 
Received 12 April 2007; Accepted 12 November 2007

/ABSTRACT:/

*Deformation and rupture of the oceanic crust may control growth of 
Hawaiian volcanoes*

Jean-Luc Got, Vadim Monteiller, Julien Monteux, Riad Hassani & Paul Okubo

Hawaiian volcanoes are formed by the eruption of large quantities of 
basaltic magma related to hot-spot activity below the Pacific Plate. 
Despite the apparent simplicity of the parent process—emission of magma 
onto the oceanic crust—the resulting edifices display some topographic 
complexity. Certain features, such as rift zones and large flank slides, 
are common to all Hawaiian volcanoes, indicating similarities in their 
genesis; however, the underlying mechanism controlling this process 
remains unknown. Here we use seismological investigations and 
finite-element mechanical modeling to show that the load exerted by 
large Hawaiian volcanoes can be sufficient to rupture the oceanic crust. 
This intense deformation, combined with the accelerated subsidence of 
the oceanic crust and the weakness of the volcanic edifice/oceanic crust 
interface, may control the surface morphology of Hawaiian volcanoes, 
especially the existence of their giant flank instabilities. Further 
studies are needed to determine whether such processes occur in other 
active intraplate volcanoes.