The Earthquake Scenario in Bangladesh
As Bangladesh is located in a tectonically active much of the country including Chittagong, Sylhet, Dhaka, Rangpur, Bogra, Mymenshing, Comilla, Rajshahi are very much vulnerable to major earthquake disaster. Although, some awareness is raised among a limited groups, due to some recent earthquakes in the region, practically the country is far behind the minimum preparedness level to face such a disaster in any of our cities.
Significant damaging historical earthquakes have occurred in and around Bangladesh, and damaging moderate-magnitude earthquake occur every few years. The country’s position adjacent to the very active Himalayan front and ongoing deformation in nearby parts of south-east Asia expose it to strong shaking from a variety of earthquake sources that can produce tremors of magnitude 8 or greater. The potential for magnitude 8 or greater earthquakes on the nearby Himalayan front if very high, and the effects of strong shaking from such an earthquake directly effect much of the country. In addition, historical seismicity within Bangladesh indicates that potential for damaging moderate to strong earthquakes exist throughout much of the country. Large earthquakes occur less frequently than serious floods, but they can effect much larger areas and can have long-lasting economic, social, and political effects.
Liquefaction is another source of earthquake related damage. During sustained strong shaking, poorly consolidated, water saturated sediments can liquefy and loose their ability to support loads. The foundations and supports of structures built on liquefiable sediments can fail, causing damage or destruction. Much of the country is of loose sandy soil and most of it remains in saturated condition round the year, thereby vulnerable to liquefaction in case of sustained ground motions.
Based on the above discussions, the probable scenario for an earthquake to a scale of M6.5 or above in Dhaka city could cause:
1. Panic among the city dwellers and no knowledge of what is to be done during and immediately after the eq. occurrence.
2. Possible sinking of many of the buildings on filled earth with shallow foundations due to the liquefaction effect.
3. If the eq. occurs during monsoon time possible damage of the Dhaka flood protection embankment due to liquefaction effect causing sudden submergence of a large area.
4. Large scale damage and some collapse of poorly constructed and/or old buildings.
5. Possible outbreak of fire in most of the buildings from the gas lines (the residential ovens are mostly in burning condition from morning to mid-night)
6. Possible damage of power installations and power cut off for indefinite period.
Debris from the Earthquake falls into the ponds,lakes, and rivers. The spilling of hazardous chemicals makes its way to the water supply as well. This kills wildlife that live in the water system, as well as the ones that use it for water or their food supply.
In the early twentieth century, San Francisco, a bustling city full of people with diverse cultures, stood in the midst of the Second Industrial Revolution. At this time, the brilliant inventions of airplanes, automobiles, and radios were changing the everyday lives of many. San Francisco had just recovered from the four-year burden of the bubonic plague (“Bubonic”). However, right when things were getting back to normal, a destructive earthquake hit the city on April 18, 1906. Although the shaking lasted for less than a minute, the devastated city had crumbled buildings and a substantial loss of lives. The San Francisco Earthquake of 1906 had a lasting effect on the city and its people, and it proved to be one of the most catastrophic disasters in history.
Disaster! Would some up how the city looked. Fire fire fire fire it was everywhere. Blood screaming ,and very mournful people everywhere. The smell of burnt skin,and the sight of ashes hugged the city. Montag Walked carefully avoiding the surviving fireman. Montag he must find montag. Montag crouched behind a trash can the scent of burnt trash wrestled his nose. “ hush up about montag you fool”. “Do you not see what dealing with montag has caused our city”. “ I mean he has avoided us all this time; books must not be that bad”. The other fireman looked at fireman William as if he had been on trial for murder. “ that’s crazy talk William”. The smoke must be getting too you”. “Books is the reasons our city is like this”.
Floods and washing away of homes was caused by the rupture of the Fujinuma irrigation dam in Sukagawa. The flooding of the dam caused the drowning of many people and was a factor in the 90% deaths by drowning. Soil liquefaction is caused by applied strength from an earthquake and is where soil behaves as if it is liquid, and at a water purification centre in Tohoku, the soil sank 1 metre. Many coastal towns and cities were destroyed as a result of the tsunami that followed the initial ground shaking. The tsunami even spread to locations across the world such as Hawaii, Ecuador, Chile, Peru, Antarctica, California, Oregon and the Galapagos Islands. However, there were no deaths due to these
D.J. Dowrick (”Earthquake Risk Reduction”in Wiley) explains that seismic hazard is any physical phenomenon associated with an earthquake that may produce adverse effects on human activities. Earthquakes occur very suddenly without any warning. Thus, earthquake not only destructs people’s living environment, but also affects people’s mental health. People are more scared of earthquake. In 2010, there are two severe earthquakes, which are Haiti Earthquake and Chile Earthquake. Both of these two earthquakes produced the various impact considerably across countries and regions. The purpose of this essay is to analyse those two earthquakes according to knowledge such as why they occur, how strong they are, and what the impact they made. Even though people still can not predict earthquake, through analyse earthquakes, they can prevent it bring huge losses.
Hazards pose risk to everyone. Our acceptance of the risks associated with hazards dictates where and how we live. As humans, we accept a certain amount of risk when choosing to live our daily lives. From time to time, a hazard becomes an emergent situation. Tornadoes in the Midwest, hurricanes along the Gulf Coast or earthquakes in California are all hazards that residents in those regions accept and live with. This paper will examine one hazard that caused a disaster requiring a response from emergency management personnel. Specifically, the hazard more closely examined here is an earthquake. With the recent twenty year anniversary covered by many media outlets, the January 17, 1994, Northridge, California earthquake to date is the most expensive earthquake in American history.
Mr. Adams describes the San Francisco earthquake as his most profound human suffering experience because the horror of shaking floors, parts of his mom’s house collapse to the floor, and got a broken nose from stumbling into a brick wall (Ansel Adams & The 1906 Earthquake 2008). Earthquakes are part of natural disasters of the earth and normally caused by shaking ground and rapid movement of one block of rock slipping past another a long fractures in the earth crust called faults. Faults that are usually locked excluding abrupt movements, which slippage creates an earthquake (Lutgens, F. & Tarbuck, E.
The effects caused by earthquakes are devastating. They cause loss of human life and have effects on infrastructure and economy. Earthquakes can happen at any time anywhere. In January 12, 2010 an earthquake of a magnitude of 7.0 hit the nation of Haiti. An estimation of 316,000 people were killed, and more than 1.3 million Haitians were left homeless (Earthquake Information for 2010). Haiti was in a terrified chaos. After the earthquake, families were separated because many of the members were killed. Homes, schools, and hospitals were demolished. People lost their most valuable belongings. It will take time for the country to recover from this terrible disaster. The long damages are economic issues, health-state, and environmental issues that effect in the beautiful island of Haiti.
Earthquakes happen about 20,000 times a year worldwide. They can destroy almost anything.In 2011, Japan had 9.1 magnitude earthquake, close to the highest magnitude of 9.2 in Alaska. They suffered tremendous damage from such a strong earthquake. The year before Haiti suffered from a 7.0 magnitude earthquake, still quite high compared to small tremors at magnitude 0-2. Japan recovered and rebuilt much faster than haiti did though. Haiti isn't even quite done recovering yet. The earthquakes had such different effects on the countries because of their economy, the condition of their people, and population rates.
On November 12th, 1970, the deadliest cyclone in the history of Bangladesh, formerly East Pakistan, struck around the northwest shores of the Bay of Bengal. East Pakistan was undergoing widespread poverty at the time, leading to a wide range of uncertainty in the death toll of the cyclone (Encyclopedia 501). Tensions between East and West Pakistan were at large at the time, leading West Pakistan to be disinclined to assisting East Pakistan in recovering from the storm (History 4). This became a factor to the national mutilation of East Pakistan (Geol 1). This calamity is by no means the strongest storm in history. The storm merely struck the worst possible place at the worst possible time (Disaster 172). Due to this, Bhola is frequently recognized as the most devastating tropical storm in history (International 5).
Flooding has always been part of the natural environment of Thailand. Since historical times populations that live within the urban and rural floodplains have learned of ways to adapt and survive (Balancing 2). With the economic development of many areas within the floodplain regions over the later part of the last century many areas have become further susceptible to seasonal rains and flooding.
... although we may never be able to understand exactly what soil failures can occur when a natural disasters take place, as time goes on and testing instruments and materials advance we will hopefully have a better understanding of what we can do to avoid soil failures and come up with a better and more sufficient method of improving the soils structure and strength permanently. While researching the information for this report I feel I have a much better understanding for construction geo-technics and foundations especially regarding the deformation, liquefaction and pile information related to this specific event. I hope to carry the information I have learned from this event into the construction field and apply them towards an authentic project that’s taking place and know that the information, regarding soils, I have given input on will be precise and accurate.
Living in Bangladesh, we have seen quite disastrous mudslides from the past few years. Mudslide is also called a landslide or a land slip. It is a downward mass movement of earth or rock on unstable slopes, including many forms resulting from differences in rock structure, coherence of material involved, degree of slope, amount of included water, extent of natural or artificial undercutting at the base of the slope, relative rate of movement, and relative quantity of material involved. There are numerous facts that can cause a mudslide and there are also numerous effects that it can cause us.
Earthquakes are vibrations felt at the surface of the earth which are caused by disturbances of the energy in the earth's interior. These vibrations are known as seismic waves. (Skinner Robinson McVerry 1) There are different type sof seisimc waves such as Primary (P) waves, whcih travel the fastest, Secondary (S) waves which cause the earth to vibrate vertically, Surface (L) waves. P and S waves are "affected by changes in the density and the rigidity of the materials through which they pass." (Columbia Encyclopedia) Earthquakes vary in their intensity and duration. Often times they are strong enough to cause massive destriction. Tall buildings often suffer as a result of these natural disasters. In recent years this has become a larger and larger threat with both the number of large buildings, and their number of occupants increasing. In an effort to try to minimize the damage caused by earthquakes many some engineers focus primarily on designing and constructing earthquake resistant buildings. Earthquake engineers have gathered much of their information from analyzing past earthquakes, and learning which buildings can and can't withstand the tremors. The goals of these engineers is to design buildings that can withstand moderate earthquakes and obtain minimal damage, and that the buildings will not collapse lowering the probability of human deaths.
Earthquakes belong to the class of most disastrous natural hazards. They result in unexpected and tremendous earth movements. These movements results from dissemination of an enormous amount of intense energy in form of seismic waves which are detected by use of seismograms. The impact of earthquakes leaves behind several landmarks including: destruction of property, extensive disruption of services like sewer and water lines, loss of life, and causes instability in both economic and social components of the affected nation (Webcache 2).