On August 29, 2005, hurricane Katrina crashed into the Gulf Coast, leaving a swath of death and destruction in its wake. And now, a year later, many people are still feeling Katrina’s aftermath. On the anniversary of hurricane Katrina, Science Buzz features a variety of links and resources. We want to hear your natural disaster stories. And Katrina survivors, we especially want to hear from you!
The Hong Kong Observatory reported that an earthquake of magnitude 6.2 has struck central Indonesia. There are not yet any reports of casualties or damages.
The National Museum of American History is in the planning stages of building an exhibition displaying numerous Hurricane Katrina artifacts. The exhibit will be on display after the museum reopens in 2008.
11,000 people have been evacuated from the area surrounding Mount Merapi, as lava and superheated gas poured from the volcano. (This is the same area affected by last week's major earthquake.) Merapi is one of the world's most active and unpredictable volcanos, and some scientists have suggested that the earthquake contributed to this latest round of volcanic activity.
On May 27, a powerful earthquake—centered about ten miles southeast of Yogyakarta—shook Java, Indonesia. It destroyed more than 135,000 houses, leaving 200,000 people homeless, and it killed at least 6234 people, injuring another 46,000. And volcanic activity on nearby Mount Merapi has tripled since the quake, sparking fears of an eruption.
The "ring of fire"
The continents rest on large plates of rock that are slowly moving around the surface of the Earth. Indonesia, a nation of more than 18,000 islands, experiences a lot of earthquakes and volcanic eruptions because it sits along the “ring of fire”—the Pacific Ocean’s zone of active volcanoes and tectonic faults.
Just south of Java, the Australian plate is moving north at two and a half inches each year. Where the Australia plate collides with the Sunda plate—which includes Java—the Australia plate slips under the Java plate in a process geologists call subduction.
Pressure builds up along the fault lines where the plates meet. When the rocks separating the plates suddenly give way, the ground shakes and buckles in what we call an earthquake. Volcanoes are formed when the subducted rock melts and returns to the surface as magma.
How strong was this earthquake?
The United States Geological Survey says the quake measured 6.3 on the Richter scale. This quake didn’t cause tsunamis like the big earthquake in December 2004. But it was shallow—only 6 miles underground—which made the shaking on the surface more intense than other quakes of the same magnitude. And the quake struck at 5:54 am local time, trapping many people in their homes.
How did this earthquake compare to others?
Tsunami warnings have been issued for Fiji and New Zealand after a earthquake of 7.8 magnitude shook the Pacific Ocean.
The quake's epicenter was about 153 miles off the coast of Tonga.
The Pacific Tsunami Warning Center issued the alert for Tonga, Niue, American Samoa, Samoa, Fiji, and Wallis-Futuna.
If a tsunami does occur, it could start to affect the islands by as early as 12:15pm (Minnesota time).
We'll post updates...
Tornado season is here for those of us living in the Midwest. Tornadoes fascinate me – they’re so incredibly powerful and stunning and scary all at once. I used to have all sorts of elaborate emergency escape plans to the basement when I was a kid, and even had a pecking order for what prized possessions I would save and how. I also remember as a kid being told that if there was the threat of a tornado to open up a window a crack before heading to the basement so that the pressure inside the house would normalize with the pressure outside generated by the tornado thus preventing the roof from being blown off. I did this all the way up until last summer – but no more.
It turns out that a majority of damage to homes is the result of wind blowing into open (or broken) windows pushing up on the roof at the same time as winds are blowing over and under them, generating a lifting force, which increases the chances of the roof being blown off. So, all this time I’ve been making my house less safe, rather than safer. Doh.
Although it is likely wishful thinking on my part to hope that a single pane of glass is going to remain intact during a tornado, especially with all the debris that will be flying around. It makes more sense to close them to keep the rain out than to save the house from tornado damage, but it feels good to do something during those times when you have no real control. Better still to just forget the windows and get to the basement. With my most prized possessions.
Scientist working in Indonesia have
found the remains of a civilization wiped out by a volcanic eruption.
Mount Tambora's cataclysmic eruption on April 10, 1815, buried the inhabitants of Sumbawa Island under searing ash, gas and rock and is blamed for an estimated 88,000 deaths. The eruption was at least four times more powerful than Mount Krakatoa's in 1883.
Interestingly, the culture wiped out by the explosion was very different from others in the area. Based on the language they spoke, some scientist had speculated these people originally came from Indochina. (Other Indonesian cultures are believed to have come from south China, via Taiwan and the Philippines.) The archaeologists have dug up pottery similar to that found in Vietnam, strengthening the possibility of a connection.
There was a 7.7 magnitude earthquake centered in Pakistan on October 8th, 2005 at 8:50am Pakistan time (that's 10:50pm on Friday in Minnesota). The earthquake devastated the region, leaving many villages destroyed and killing thousands in Pakistan and India. It is one of the strongest earthquakes to hit this area in living memory. Pakistan's president Pervez Musharraf described the disaster as the country's "worst-ever."
The earth's continents rest upon large plates of rock that are slowly moving around the surface of the earth. For millions of years, the Indian subcontinent has been slowly moving north towards Europe and Asia (Eurasia). About 40-50 million years ago (mya), India slammed into Eurasia. Because both India and Eurasia were continents the Eurasia crust crumpled upwards, creating the Himalayan mountains. The leading edge of India was eventually forced underneath the continent in a process geologists call subduction. This movement is still happening today. However, as India continues to move slowly north, it gets hung up and energy builds. When enough energy builds up, there are short bursts of movement, releasing this massive energy and shaking and buckling the ground in what we call an earthquake.
In the last hundred years, several other earthquakes of similar strength have struck this region: