Strong quakes of foreshock and aftershock for main tremor of M6.5 (initially reported M6.9 but later down to 6.5) at 2:31 PM NZ time rocked newzealand south island. Epicenter was in the north east tip of south island, which is near to the capital city wellington. On the same area about three weeks ago there was tremor of M6.5 caused several damages. Yesterday there was no any report of even serious injury, many people came down to the ground and evacuated to safe places. several people who trapped in elevators were successfully rescued. There were several structural and non structural damages.
Saturday, August 17, 2013
Tuesday, August 13, 2013
How bullets are loading on earthquake gun in developing countries??
When earthquake of level around M6.5 occur in Japan hardly claim life but if the same level will be in Indonesia, Philippines, India, Myanmar, Nepal, Pakistan, Afghanistan etc. countries will have to loss in several thousands? Bryan Walsh wrote in TIME as earthquakes are gun and structures are bullet that load on gun and fire to people. He specially focus on south central Asia about earthquake and disaster in his last article How Shoddily Constructed Buildings Become Weapons of Mass Destruction . I totally agree with his article that main problem developing countries are not focused on implementation of seismic design and building codes to public during their private building constructions, hardly they follow for just civic buildings.
Most of the structures in rural areas are still stone masonry in mud mortar, during rainy season even they are more vulnerable to collapse with wetting of mud mortar, even they are as like the stack of stones so they cant hold more tremor intensity and fall down as blow on head. Rural area people must have to aware about seismic risk and its mitigation during construction of their house, with just a small additional amount (about 10%) investment on their house they can get more safer (about double ) building. Rural settlements are also catering more population in developing countries even up to now.
Saturday, August 10, 2013
Earthquake alert message in Japan went wrong
August 08, 2013 at 4:56 PM, i was in my research laboratory concentrating on some programs of my research, In laboratory there are also other friends who are busy on their own task, Cell phones of one friend start to ring and vibrate on different sound, then all of us just little bit confuse about that sound but later with in seconds all of our cell phones display emergency message about the great earthquak . All of us took precautions and just hide under the table but up to few minutes we did not feel any tremor then we just came to normal schedule.
This is the message received on my cell phone
Japan had the best system to issue the emergency warnings (you can see here about earthquake warning system in Japan ) on such events so everyone cares about such message. Messages are not only displayed on mobiles but they automatically broadcast from televisions also. After this message all the train lines got emergency stops, several factories went to just stuck, Hospitals, schools, public areas all got alert. People scared and and remembered one devastating great east Japan earthquake 2011 march.
Mega cities and rural area : Linkage and problems
A megacity is usually
defined as a metropolitan area with a total population in excess of 10 million people. Some definitions also set a minimum
level for population
density (at least 2,000 persons/square km). A megacity can be a single metropolitan area or two or more metropolitan areas that converge. The terms conurbation, metropolis and metroplex are also applied later. Top ten megacities are tabulated
here as per the data 2013 April.
List of top 10 mega cities
Wednesday, August 7, 2013
Confirmed 1906 San Francisco Earthquake fault after century
In 1906 there was a great San Francisco M7.7 Earthquake and fire following earthquake, that cause almost 664 casualties and 225,000 homeless among 400,000 population. More than 28,000 buildings collapsed and loss of more than $400 million of monetary value.
San Andreas fault earthquake cut a trench in 1906 through Portola valley. Seismologists and Geologists are on debate about the source of this earthquake due to poorly reproduced historical map. They are debating for the location of fault that cause earthquake in 1906 was in east and west. Now, Chester Wrucke, a former U.S. Geological Survey geologist, and his son Robert Wrucke, open up the cover to all geologist about rupture. They confirms only west side fault was ruptured during earthquake and also they find the exact location of fault that crosses Alpine road. They compared the 1906 photos to publicly available bare earth lidar imagery of the valley, tracing the historic ruptures onto the modern topography. Bare-earth lidar is an airborne laser measurement technique that results finely detailed topography, free of trees and brush.
Some photographs of that earthquake are here
Monday, August 5, 2013
Earthquake Warning System in Japan
Earthquake is an event when two main plates collide each other in their boundaries for strong shaking, small level of earthquake are even felt by mining, volcanic activities too. Moderate level of earthquake may cause due to inter plate(when in boundary of two major plates) or intra-plate (in between small plates with in major plate). Earthquake produces major waves that they called P-wave and S-wave from the source which travel through the body of earth and reach up to ground surface. In ground it changes in to surface waves and cause tremors on ground so we feel shaking.
Velocity of P-wave is higher than S-wave when they produces in same time during earthquake but they reach to surface in lag of time. S-wave which is slower in its velocity is main responsible for damage to structures. If we can beware before few seconds then we can manage possible safety in any situation. Up to now scientists could not achieve the accurate results of forecasting earthquake but the research is in progress from different aspects may be in near future they can be able to save lives. Now a days, Japan Meteorological Agency (JMA) has earthquake warning system launched on October 1st 2007. This is based on the phenomenon that P and S waves have different velocities.
How it works?
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