Bangladesh - Natural Hazards

 Natural Hazards: 

Bangladesh is prone to a variety of natural hazards. It has witnessed the havoc of some of the best natural disasters of the world due to tropical cyclones and storm surges. Floods and local seasonal storms are annual events which cause loss of lives and damage to housing, agriculture and economy. The country is also exposed to the risk of earthquakes and possibly tsunami too. There are other natural hazard concerns such as coastal erosion and sea level rise due to global warming, which also need to be dealt on a long term basis.

Bangladesh is located close to the plate boundary between the northward moving Indian plate and the Eurasian plate. During 1245-2200, five earthquakes with magnitude M≥7 have affected parts of Bangladesh. Two of them had their epicentres inside Bangladesh. Repeat of similar earthquakes which appears to be quite likely can now cause great devastation due to the rapid growth of densely populated urban areas. with construction lacking quality as well as earthquake r-sistant design. Even moderate earthquakes close to the urban cities may cause great havoc. In rural areas of high seismic risk, highly vulnerable mud-walled houses isareuite common. During the last seven or eight years, the occurrence and damage caused by some earthquakes (magnitude between 4 and 6) in the south-eastern part of the country inside the country or near the country’s border, has raised the level of awareness among the general people and the government as well.

As part of an ongoing study for the re-assessment of the probabilistic seismic hazard for Bangladesh, an earthquake catalogue has been formed and seismic source zones capable of producing significant earthquakes have been delineated. Using the characteristics of earthquake occurrence in these zones, the probabilistic seismic hazard for Bangladesh can be estimated. Sensitivity analysis will be conducted to determine the effect of different parameters on the seismic hazard. The local soil effect represented in the 1993 Bangladesh National Building Code has been re-examined. Seismic site response estimation using 1D wave propagation analysis is performed for Dhaka city (capital with a population of over 10 million) soils and it is found that the response spectra given in the code is underestimating the ground motion. Revision of existing code is necessary.

Bangladesh has achieved remarkable success in disaster management (early warning and post disaster management) related to floods and tropical cyclones. But very little has been done with regards to earthquake. The Bangladesh government is currently planning abouhrough a comprehensive disaster management program (CDMP). An Integrated multi-hazard disaster reduction is the nation’s top priority. To make it successful, it is necessary to improve co-ordnation among different organizations (including academic and research institutions) and programmes.

link: http://www.mssmat.ecp.fr/Natural-Hazards-in-Bangladesh-with,2381

link: http://en.wikipedia.org/wiki/Category:Natural_disasters_in_Bangladesh