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Archive for the ‘Tectonics’ Category

Hurricanes might trigger big tropical earthquakes

Posted by Lindy on December 12, 2011

This is a very interesting idea but read it carefully to see what they are saying but also appreciate what they are not.

A new study by Professor Shimon Wdowinski may help scientists identify regions at high risk for earthquakes. By dumping rain and causing landslides, these storms can change the weight of the Earth in tectonically-stressed regions, releasing loads that had been keeping the faults locked in tight. The result is that faults already under pressure seem more likely to break in the years after very wet tropical cyclones.

Earthquakes including Haiti’s 2010 magnitude-7.0 temblor and a 6.4-magnitude quake that struck Kaohsiung, Taiwan, the same year, fit this pattern.  These quakes were preceded by drenching storms that wreaked other kinds of havoc. “The cyclone itself is a disaster, there is a lot of flooding, then there are landslides and then the earthquakes come,” Wdowinski said.

Disaster chain reaction

Widowinski became interested in whether tropical cyclones interact with earthquakes after noticing that both the 2010 Taiwan earthquake and the 2010 Haiti quake were preceded relatively closely by big storms. In the case of Taiwan, 2008’s Typhoon Morakot had dumped 115 inches (292 centimeters) of rain in just five days. In the case of the Haiti quake, the 2008 hurricane season had been brutal, with named storms (hurricanes and tropical storms) Fay, Gustav, Hanna and Ike tearing into the island. The researchers decided to see if the timing was a coincidence or whether it meant something more. They turned to Taiwan, which has good records of the past 50 years of quakes and storms.

Focusing only on very wet typhoons with the capacity to cause of a lot of erosion, and removing aftershocks that would bias the analysis, the researchers found that 85 percent of magnitude-6-and-above quakes occurred within the first four years after a very wet storm. That was five times what would have been expected from background quake rates. Even smaller quakes followed the same pattern, with 35 percent of magnitude-5-and-above quakes occurring within the first four years after wet storms — twice the expected number.

Timing is everything

Previous researchers have suggested that extremely low pressure from storms can trigger quakes in already-strained areas in the very short term but these longer-term linkages are likely caused by a different mechanism. These areas are already tectonically active, with faults building up strain as landmasses creep against one another. These strained faults are destined to rupture and eventually cause quakes.

But when a very wet typhoon or hurricane dumps lots of rain, it often causes large landslides in mountainous areas. Extra rain over the following months further erodes mountains and hills scarred by these landslides. This shifting of sediment lifts the weight that keeps faults locked. The burden lifted, the fault suddenly slips, causing a quake. These quakes are likely not any larger or smaller than they otherwise would have been, but the presence of very wet storms may give a hint that a quake-prone region is at higher risk of rupturing in the following years.

“The main engine that’s actually responsible for the earthquake is not the wet typhoon,” Wdowinski said. “The wet typhoon just determines the timing.”


Posted in Hazards, Physical Geography, Tectonics, Weather | Leave a Comment »

Turkish Quake Highlights Shoddy Construction

Posted by Lindy on October 28, 2011

Follow up ion the impacts of the Earthquake in Turkey

Two things are for certain in Turkey: The country will have earthquakes, and those earthquakes will continue to kill.  Turkey faces a fatal combination of geography and history. It lies at the intersection of the Anatolian, African, Eurasian and Arabian tectonic plates, and its building codes have been lightly regulated for centuries —  meaning that earthquakes will be deadly here for years to come.

Despite tough safety codes approved a decade ago after earthquakes killed 18,000 people and prompted an outcry over the poor quality of construction, enforcement has remained lax. After the latest disaster — a magnitude-7.2 temblor that killed hundreds on Sunday — some residents in the

worst-hit town of Ercis said some of the pancaked buildings lacked steel support rods and sufficient concrete, and accused builders of sacrificing safety for speed and economy.

“Death comes from God. But what about poor construction?” asked Nevzat Altinkaynak. “Look at this building. It was new. It didn’t even have paint on it yet!” Altinkaynak waited outside a collapsed building for news of his wife, Ayse, after rescuers pulled out his daughter Tugba alive.

On Wednesday, the prime minister weighed in, charging that shoddy construction contributed to the high casualty toll and that Turkey had not learned lessons from past disasters. “When we look at the wreckage, we see how the material used is of bad quality,” Prime Minister Recep

Tayyip Erdogan said. “We see that people pay the price for concrete that virtually turned to sand, or for weakened concrete blocks on the ground floors. Municipalities, constructors and supervisors should now see that their negligence amounts to murder.” He said: “Despite all previous disasters, we see that the appeals were not heeded.”

Some 2,000 structures were demolished in Sunday’s quake, including about 80 multistory buildings in Ercis. Serdar Harp, head of Turkey’s Civil Engineers Chamber, told Milliyet newspaper on Tuesday that area  buildings constructed before January were not properly inspected despite the stricter building codes that went into force in 2001, two years after devastating earthquakes in western Turkey.

Many of the people killed by the 1999 quakes died in cheaply made housing blocks that pancaked, and which were later revealed never to have been inspected. Further investigation revealed that much of the cement lacked metal reinforcing bars, or was mixed with large amounts of sand that made it unstable.

The latest disaster revealed similar construction shortcomings, residents said. Harun Uzmez, a fireman experienced in quake rescue, picked up a piece of rubble from the wall of a 20-year-old, five-story building that housed several families. He poked at it, and dust flew off. He dropped it, and it broke into pieces. “It was all sand and lime,” he said. He said iron rods used in the columns of the building were not strong enough.

The disaster in eastern Turkey came a year after a parliamentary report concluded authorities were failing to enforce new building codes, which stipulate that construction cannot begin until plans prepared by authorized  architects and construction engineers are approved by inspectors.  Authorized engineers are also supposed to inspect the construction while it’s under way to make sure the quality of cement is good enough and sufficient steel rods are used.  The parliamentary report said Turkey has also failed to improve city planning, reinforce substandard buildings, control urban development and punish people who violate building codes. It warned that several Turkish cities are at risk.

Foremost among them is Istanbul, which sits near a major fault line and has a population of 15 million.  Geologists have urged the government to tear down some 40,000 buildings there that would probably collapse in a big quake, and have warned that hundreds of thousands more need to be reinforced.

But some engineers said Sunday’s quake was so strong that even properly built buildings would have collapsed.  Shaking associated with a magnitude-7.2 quake “can cause collapse of buildings even with moderate seismic design and quality construction,” according to Mishac Yegian, a professor of civil engineering at Northeastern University in Boston.

“Careful evaluations of the collapsed and survived buildings can reveal how much the extremely high intensity ground shaking, or deficiencies in design and construction contributed to the disaster,” Yegian said. “It is the tendency of people at early stages to fault the designs and quality of construction.”

Posted in Hazards, Tectonics | Leave a Comment »

The first good news about predicting earthquakes

Posted by Lindy on May 20, 2011  to see the images.

Scientists say that the atmosphere above the epicenter of Japan’s catastrophic March 11 earthquake underwent significant changes prior to the tectonic thrust.

Preliminary studies of the phenomena by Chapman University researcher Dimitar Ouzounov and several international colleagues could offer insight into how to predict powerful earthquakes well before they strike.

Using satellite data, they studied atmospheric conditions during the days leading up to the quake.

They found a large increase in the concentration of electrons above northeastern Japan, which peaked three days prior to the quake.

March 8 also saw a rapid increase in infrared radiation above the future epicenter. Both atmospheric changes disappeared following the main 9.0 magnitude quake.

Similar phenomena have been detected prior to some other major earthquakes.

Posted in Hazards, IGCSE, Tectonics | Leave a Comment »

Spanish Earthquakes 11th May 2011

Posted by Lindy on May 13, 2011

2 quakes of 4.4 and 5.2 hit the town of Lorca which has a population of about 90,000. 10 were killed in the quakes, and a lot of masonry fell, and there was some structural damage, in particular to older buildings.

Many people camped out on Wednesday night rather than risk being inside during after shocks. There were long queues for food and water.

But why was such a small earthquake so deadly? Many earthquakes with a scale of 5.2 have little impact. How was this one different? It is all to do with the depth of the focus – the nearer to the surface it is, the bigger the shock waves on the surface – and this one was very close, barely 1km down. Compare this with the recent earthquake in Japan, that was a scale 9, where the depth was 32km.

From our local correspondent, Shannon Robertson:

My mum was lying on the beach and she felt the sand move in a circular motion underneath her. She was going to say ” Did you guys feel that?” but we were two busy playing. Anyway, when we got home from the beach, my mum had a FB message saying “Spanish earthquake killed 10 people in Lorka, did u feel it?” and my mum said to my dad “i felt the earthquake on the beach.’

Posted in IGCSE, Tectonics, Y7/8 | Leave a Comment »

Amazing pictures of Mid-Atlantic Ridge

Posted by Lindy on May 11, 2011

Posted in IGCSE, Tectonics, Y7/8, Y9 | Leave a Comment »

Art gives a new life to 350 Haitian families

Posted by Lindy on May 1, 2011


It’s spring, and signs of Haiti’s economic recovery are popping up in surprising ways: handcrafted quilts from Port-au-Prince, papier-mâché vases from Jacmel, and jewelry from Croix des Bouquets — all on store shelves throughout the United States, said a statement from the Clinton Bush Haiti Fund.

More than 350 Haitian families are now able to provide food and afford schooling for their children thanks to the incredible success of our Fairwinds Trading project. This program is enabling a community of Haitian artists to produce market-ready goods for sale in the United States, and it’s been very successful thanks to multiple orders from retailers like Macy’s and Anthropologie.

The Clinton Bush Haiti Fund awarded a loan of $174,832 to Fairwinds Trading in January of this year. Fairwinds Trading supports hundreds of artisans by giving them the logistics support, design guidance, and the US market connections that they need to export their art.

The artists participating in this program are eager to earn their own livelihoods, proud to contribute to their “Ayiti Cheri” and are very optimistic, an optimism that is contagious and that energizes the whole community.

Posted in Fragile environments, Haiti, Hazards, IGCSE, Solution to problems, Tectonics, Y7/8 | Leave a Comment »

Worried about a nuclear explosion in Japan?

Posted by Lindy on March 13, 2011

Just follow this link to find out why you shouldn’t be.

More on Japan later

Posted in Hazards, Tectonics | Leave a Comment »

Haiti – Reconstruction : Approximately one third of the refugees have found shelter 22/01/2011

Posted by Lindy on January 22, 2011

One third of the 1.5 million individuals who have been living in “tent cities” have relocated to date, with another 400,000 expected to relocate over the next 9 months.

This has been achieved by:

  • The return of families to homes that have not only been  fully repaired, but are sturdier and more resilient than before the quake;
  • Temporary housing in people’s neighbourhoods of origin;
  • The repair of building that can be achieved relatively cheaply and quickly.

Underway are:

  • A rural project to build a village for 3000 Haitians by Mission of Hope Haiti
  • A World Bank project to repair houses and build 5000 new housing units in the city
  • A USAID to finance 15,000 serviced sites in new communities in the Cap Haitien and Port-au-Prince  [ A version of a self help project – see urban unit]
  • A  USAID financed housing and neighbourhood upgrading in earthquake-damaged communities for 10,000 households.

Posted in Development, Haiti, IGCSE, Solution to problems, Tectonics, Urban environments | Leave a Comment »

Lahar destroys farmlands

Posted by Lindy on January 7, 2011

5 Jan 2011

In Magelang, in Central Java on Tuesday. Lahar from the slopes of Mount Merapi has caused chaos in the area. Thousands were forced to flee their homes as lahar from the slopes of Mount Merapi inundated hundreds of houses and destroyed hundreds of hectares of agriculture fields on Monday evening.
Heavy downpours since the afternoon in the regions sent thick layers of volcanic debris down the slope of Merapi, carrying logs and volcanic rocks of up to 2 meters in diameter, destroying everything they hit along the way. The lahar destroyed at least two bridges and four houses.

The administration  had also been normalizing the stream along the river and deployed heavy equipment at the locations in case they were needed.Two excavators were deployed to help normalize the highway. However, due to the thick layers of volcanic materials, they had not yet been able to completely clear them from the road as of Tuesday afternoon.

Lahar will continue to threaten areas along the banks of the 12 rivers originating at Merapi as those rivers are still filled with thick layers of volcanic materials of up to 17 kilometers down their streams, ready to travel as heavy rain pours over the region.

Posted in Hazards, Physical Geography, Tectonics, Y9 | Leave a Comment »

Solar lights the way for a new Haiti

Posted by Lindy on December 9, 2010


Before the January 12th earthquake, only 12.5% of the population was joined to the electricity grid. After the quake, diesel fuel was more difficult to get and more expensive. Much of Haiti was left in darkness. But solar power could be the light at the end of the tunnel.

Thousands of LED handheld lanterns have been issued, together with solar district lighting. Solar cookers and solar purification plants are now being shipped in. The latter are even more important since the outbreak of cholera, which has not been seen in Haiti for several generations.

But this solar input is not just as a result of the quake. As early as 2008, researchers were in Haiti to see what sources of power, that could be provided by solar, would best meet the needs of the people there.

Dan Schnitzer conducted surveys asking residents what kind of help they most wanted in conquering their energy woes. He found that the average Haitian family spent 10 percent of its annual $1,200 income on kerosene and candles and another 5 percent on charging up their cell phones at 25 cents a pop.

He presented them with a list of 10 technologies including solar-powered streetlights and community facilities, biofuel systems, home solar systems and portable solar lights. More than 75 percent of the 300 or more Haitians he surveyed said they were most interested in home solar systems and portable solar-powered lights.

Schnitzer and his partners decided to open a retail store selling home solar systems for $240 that would provide a basic home with energy-efficient lighting and enough extra power to charge a cell phone. The $240 kits are complete with installation, wires, battery back-up and light bulbs, he said. The store opened in July 2010.

But this work was quickly overtaken once it had been realized how many women and children were at risk of attack in the camps, largely due to lack of light. So solar lights for the tents and hand held torches became a priority for many NGOs.

Posted in Appropriate technology, Haiti, Hazards, Tectonics | Leave a Comment »