But no update on Wednesday.
Karen Lamb
LARGEST QUAKES -
Today -
3/13/12 -
5.2 VANUATU
5.4 OFFSHORE CHIAPAS, MEXICO
5.0 SOUTH OF FIJI ISLANDS
5.0 COMOROS REGION
Yesterday -
3/12/12 -
5.6 KURIL ISLANDS
5.6 NORTHWESTERN KASHMIR
3/11/12 -
5.3 SOUTHERN MID-ATLANTIC RIDGE
5.0 VOLCANO ISLANDS, JAPAN REGION
5.0 ANDREANOF ISLANDS, ALEUTIAN IS.
5.3 CARLSBERG RIDGE
5.0 SOUTH OF FIJI ISLANDS
VOLCANOES -
Italy - The volcanic caldera on the picturesque tourist island of Santorini is showing signs of unrest. But researchers detecting the caldera's movement say it doesn't necessarily mean an eruption is imminent. The Greek island was the site of one of the most massive volcanic eruptions in history 3,600 years ago. That eruption, which created tsunamis 40 feet (12 meters) tall, may have spawned the legend of the lost city of Atlantis. The volcano last erupted in 1950, on a much smaller scale.
Global positioning system (GPS) sensors placed on the caldera have detected renewed movement after decades of peace. The earth around the caldera (a depression at the top of a volcano) is deforming, or expanding outward. GPS instruments on the northern part of Santorini have moved between 1.9 and 3.5 inches (5 to 9 centimeters) since January 2011. "What we're seeing now is the first significant deformation and the first deformation that has any significant earthquake activity associated with it." In the same time period, the magma chamber under Santorini has swollen by almost 500 million cubic feet (14 million cubic meters).
It's unlikely that the deforming caldera portends an eruption. Excavations of extinct volcanoes suggest that 90 percent of the time, below-ground magma movements don't end in eruption. A similar caldera system, the Long Valley Caldera in California, started deforming in 1980. It then quieted again until 1989, repeating the cycle in 1997 and 2002, with nary an eruption. If a Santorini eruption did occur, it would be nothing like the Minoan eruption of 1650 B.C. That eruption was a once-in-100,000-year event, and the expansion of the magma chamber happening now is only 1 percent of what would have gone on prior to the ancient blast. Geophysicists are keeping an eye on the caldera, however. An eruption could generate local tsunamis within the Santorini archipelago, damaging ports and disrupting ship traffic. Even if the volcano doesn't erupt, the shifting caldera could increase earthquake risk, and the island cliffs are vulnerable. "We don't need an eruption to have earthquake-induced landslides." There's no telling how long the deformation will continue, but it could stretch years or decades, perhaps cycling between activity and peace. "It is one of very few of these really large caldera volcanoes. So any information we gather from ongoing activity adds significantly to our database of how these systems evolve."
TROPICAL STORMS -
In the Indian Ocean -
Tropical cyclone 17s (Lua) was located approximately 285 nm north of Learmonth, Australia.
Australia - The cyclone threat to Darwin is easing, with a tropical low heading further south than forecast and failing to gain strength as expected.
