Earthweek: A Diary of the Planet (Jan. 10, 2014)

Cold War Legacy
Earth's upper atmosphere is still littered with radioactive particles from the more than 500 above-ground nuclear tests that took place decades ago, according to a new study.  Most of the plutonium and cesium isotopes from those blasts have since been rinsed out of the lower atmosphere by falling in rain or snow, or by being brought down by gravity.  The stratosphere was also thought to be relatively fallout-free before a Swiss team found its contamination to be about 1,000 to 1,500 levels higher than in the troposphere, the layer just above the surface.  Jose Corcho of the Swiss Federal Office for Civil Protection says the contamination probably poses no danger to humans.  "Most of the radioactive particles are removed in the first few years after the explosion, but a fraction remains in the stratosphere for a few decades or even hundreds or thousands of years," said Corcho.
Frost Quakes
The most brutal chill in decades, which plunged the American Midwest and parts of southern Canada into a sudden deep freeze, also triggered loud booms that sounded like explosions or falling trees.  Meteorologists assured nervous residents that the sounds were being caused by a relatively rare phenomenon known as "frost quakes."  The booms occur when water in the soil freezes and expands in extreme cold, causing the ground to suddenly fracture like a jar of water in the freezer.  Also known as cryoseisms, they can only happen when when the ground has been saturated by heavy rain shortly before a quick freeze sets in.  Such conditions have not occurred on a large scale in North America for decades, lleaving some people experiencing the quakes for the first time in their lives.
Heat Fatalities
A spell of scorching summertime weather in Australia's Queensland state killed as many as 100,000 bats in an ecological disaster officials called unprecedented.  Many of the flying foxes, or fruit bats, fell dead from the sky while the carcasses of others hung on branches.  Residents said the stench of decay was unbearable as temperatures reached nearly 110 F.  At least 16 people were reportedly receiving anti-viral treatment after coming into close contact with a bat.  The animals sometimes carry lyssavirus, which can cause paralysis and even death in humans.  But wildlife officials say the flying foxes are a key part of the ecosystem, and such a massive loss to their populations will have consequences.  The Royal Society for the Prevention of Cruelty to Animals was caring for many young bats left orphaned by the heat disaster.
Eruption Swarm
Sumatra's Mount Sinabung erupted 115 times during a three-day period in a relentless eruptive phase that began in September, sending even more people fleeing its flanks.  The volcano sent superheated clouds of debris cascading down its slopes and lava streams flowing for miles.  Residents of more than two dozen villages have been living in temporary shelters outside a 3-mile danger zone, some for months.  Many of their homes and farms have been blanketed with a thick layer of ash and other debris while they've been gone.  Indonesian geologists say magma beneath Sinabung is rising from deep within the Earth, swelling the size of the lava dome near its peak.  That dome occasionally collapses, triggering pyroclastic clouds and gushes of lava.  Sinabung roared to life in 2010 after lying mainly dormant for 400 years.
Tropical Cyclones
The island nation of Tonga was buffeted by gales and heavy rain as Category-2 Cyclone Ian churned the waters of the South Pacific.
*     Cyclone 01B formed briefly over the southwestern Bay of Bengal, but lingering clouds brought three days of downpours to a swath of Sri Lanka.
Earthquakes
Weak tremors were felt around the South Australia capital of Adelaide and in southern Bulgaria, coastal areas of metropolitan Los Angeles and southeastern Nebraska.
Shark Tweets
Surfers and swimmers on popular Western Australia beaches can now get warnings of nearby sharks thanks to new wireless technology and Twitter.  Marine biologists have attached tiny transmitters to more than 320 sharks, including great whites.  Their progress up and down the Indian Ocean coast is monitored, and a computer automatically sends out shark alerts via short messages on Surf Life Saving Western Australia's Twitter feed.  Details about the size, species and approximate location of the fish are provided.  Western Australia is the world's deadliest place for shark attacks.  Surfer Chris Boyd was killed in November and was the sixth person to die from shark attack in the region during the past two years.  The new alert system went online just days after a controversial law was approved allowing fishermen to kill sharks largerthan 5 feet in lenght if they are found in some areas used by surfers and swimmers.