George Washington
LARGEST QUAKES -
This morning -
5.0 PHILIPPINE ISLANDS REGION
Yesterday -
2/23/12 -
5.0 NEAR EAST COAST OF HONSHU, JAPAN
5.2 KERMADEC ISLANDS REGION
5.1 OFFSHORE CHIAPAS, MEXICO
5.2 NEW BRITAIN REGION, P.N.G.
5.3 SOUTHERN MID-ATLANTIC RIDGE
5.2 FIJI REGION
Earth's 'rhythmic throbbing' may lead to extinctions every 60 million years - A mysterious cycle of booms and busts in marine biodiversity over the past 500 million years could be tied to a periodic uplifting of the world's continents. Researchers discovered periodic increases in the amount of the isotope strontium-87 found in marine fossils. The timing of these increases corresponds to previously discovered low points in marine biodiversity that occur in the fossil record roughly every 60 million years. "Strontium-87 is produced by radioactive decay of another element, rubidium, which is common in igneous rocks in continental crust. So, when a lot of this type of rock erodes, a lot more Sr-87 is dumped into the ocean, and its fraction rises compared with another strontium isotope, Sr-86." An uplifting of the continents is the most likely explanation for this type of massive erosion event.
"Continental uplift increases erosion in several ways. First, it pushes the continental basement rocks containing rubidium up to where they are exposed to erosive forces. Uplift also creates highlands and mountains where glaciers and freeze-thaw cycles erode rock. The steep slopes cause faster water flow in streams and sheet-wash from rains, which strips off the soil and exposes bedrock. Uplift also elevates the deeper-seated igneous rocks where the Sr-87 is sequestered, permitting it to be exposed, eroded, and put into the ocean."
The massive continental uplift suggested by the strontium data would also reduce sea depth along the continental shelf where most sea animals live. That loss of habitat due to shallow water could be the reason for the periodic mass extinctions and periodic decline in diversity found in the marine fossil record. "What we're seeing could be evidence of a 'pulse of the earth' phenomenon. There are some theoretical works which suggest that convection of mantle plumes, rather like a lava lamp, should be coordinated in periodic waves." The result of this convection deep inside the earth could be a rhythmic throbbing - almost like a cartoon thumb smacked with a hammer - that pushes the continents up and down. The data suggests that such pulses likely affected the North American continent. The same phenomenon may have affected other continents as well, but more research will be needed to show that.
VOLCANOES -
Hawaii - Scientists at the USGS Hawaiian Volcano Observatory are keeping an eye on a swarm of small earthquakes around the active Kilauea volcano. The swarm of small earthquakes was located about three miles from the summit of Kilauea volcano on the Big Island. More than 60 earthquakes were recorded after 1 am Wednesday.
TROPICAL STORMS -
No current tropical storms.
Another Tropical Cyclone May Target Madagascar - The southwestern Indian Ocean could see a new tropical cyclone by Sunday. Were a cyclone to form in the area, it could pose a threat to Madagascar, which was dealt a destructive blow by Severe Tropical Giovanna in mid-February. Likewise, the Mascarene Islands, Mauritius and Reunion, could also feel the effects of any cyclone in the area.
The area favorable for development of a tropical cyclone will be a broad swatch of warm tropical ocean well east of northern Madagascar. Once formed, steering winds would then guide the weather system to the west and southwest. Destructive landfall by Giovanna happened shortly after midnight on Feb. 14 near Toamasina, on the east coast of Madagascar. The storm swept inland, unleashing torrential rain and damaging winds in the capital, Antananarivo. (map)
Killer Cyclone Giovanna dumping sediment into Indian Ocean - Throw a 145-mph tropical cyclone accompanied by 10 inches of rain against a low-lying coastline, and you get flooding that New Orleanians can easily understand. The most recent such incident is the horseshoe-shaped path of the Indian Ocean Tropical Cyclone Giovanna, which made landfall on the narrow east coast plain of Madagascar as a Category 4 storm on Feb. 9. Giovanna cut across the island’s mountainous plateau center before entering the channel separating it from Mozambique, and then curved south and back east around the island’s southern tip, churning back into the Indian Ocean, where it was still producing 30-mph winds Wednesday. Giovanna has killed at least 23 people in Madagascar and left about 190,000 homeless in the last week. The sediment-choked Onibe River on Saturday was delivering a thick plume of sediment to the Indian Ocean, similar to the sediment delivered to the Gulf of Mexico by the rain-swollen Mississippi River last fall. But Madagascar’s narrow range of topography, dropping from 9,436 feet to sea level over just 75 miles, results in fast-moving water picking up huge amounts of mud and debris as Giovanna exited the area. (photo)
HEAVY SNOW / EXTREME COLD -
India - Sixteen soldiers killed in avalanches. Two massive avalanches in snowbound regions of Indian-controlled Kashmir have killed at least 16 soldiers, and at least three others were feared trapped in a military camp that was partially buried under snow.
HEALTH THREATS -
H5N1 bird flu infection may be more common, less deadly, than thought.
