Quantitative analysis of earthquake fatalities: case of Iran

Earthquakes in Iran are major and chronic disasters, but there is a seemingly downward trend in the number of lives lost from earthquake disasters in the past five decades. This paper particularly examines whether factors such as urbanization, literacy rate, wealth, and retrofitting measures have contributed to the declining trend of fatalities over past decades. Data records of 1960–2010 have been used to demonstrate the fatalities trend and a shorter series of 1990–2010 has been used to carry out a statistical analysis due to limited availability of information on retrofitting practices in the country. Regression models run in two stages. The first stage consists of normalized fatalities of Iran’s earthquakes, regressed on urbanization, wealth, and retrofitting. The second stage involves the measure of retrofit as the dependent variable regressed over urbanization and/or wealth as explanatory variables. The resulted regression models clearly explain the importance of retrofitting measure in saving lives in earthquakes disasters, as well as providing economic advantages and robust environment to the population. The study provides significant guidance for public policy. Undoubtedly, retrofitting, started in the country from 1990, has decreased the number of deaths; nonetheless, the measure is found to be mostly enforced in the cities and not in rural areas. Decision makers can use the results of this study to prioritize retrofit in rural areas, more than ever, and as much as possible.     

Source measurement effect on high fidelity vibratory seismic separation

High Fidelity Vibratory Seismic (HFVS) acquisition and separation can play an important role in today's land acquisition schemes. The method – in which multiple vibrators are swept simultaneously using sweeps with known phase encoding and then the data are inverted and separated into individual records – can improve productivity in the field and at the same time improve signal characteristics in the data. It relies on the measured weighted sum of accelerations (base plate and reaction mass) to invert the acquired data and separate the individual vibrator responses. Separation can be sub-optimal if the measured motions vary from the 'true source' input into the ground. Differences in true source and measured source can arise due to poor coupling between vibrators and ground, soil compaction or other factors. Using both a synthetic model and real data, we show that if the true source changes between sweeps but is not measured, vibrator responses can leak into adjacent vibrator responses upon separation. In a recent survey with HFVS acquisition, we observed a 25–30 dB separation between adjacent vibrators, which could be improved with greater reliability of the source measurement. The vibrator leakage can reduce the data quality considerably. We discuss the results of this survey and show that separation is affected by source measurement error. Further, we conclude that it is necessary either 1) to use source measurements that can capture the variability of the true source between sweeps or 2) to compensate for the source measurement variations in processing or in acquisition.     

Is it possible to rank hurricanes in a unique manner?

This paper demonstrates that there is no unique manner in which hurricanes can be ranked. Land-falling hurricanes during the period 1960–2012 on the east coast of the United States were considered in the research. Hurricanes can be ranked using various criteria, and therefore, ranking can be different according to the criterion used. A total of 30 hurricanes were found to stand out using ten different criteria to define the severity of the hurricanes.     

Analysis of the Tsunami of December 26, 2004, on the Kerala Coast of India—Part III: Inundation and Initial Withdrawal

During the Indian Ocean tsunami of December 26, 2004, specific observations were made by our survey team about the arrival times of several tsunami waves, their amplitudes, maximum extent of horizontal inundation on land and initial withdrawal of the ocean. Here the observations on the horizontal inundation and initial withdrawal are presented and briefly discussed.     

Analysis of the Tsunami of December 26, 2004, on the Kerala Coast of India—Part III: Inundation and Initial Withdrawal

During the Indian Ocean tsunami of December 26, 2004, specific observations were made by our survey team about the arrival times of several tsunami waves, their amplitudes, maximum extent of horizontal inundation on land and initial withdrawal of the ocean. Here the observations on the horizontal inundation and initial withdrawal are presented and briefly discussed.     

Tsunami Travel Time Atlas for the Atlantic Ocean

Compared to the Pacific Ocean, tsunamis are rare both in the Atlantic and Indian Oceans. However, the December 26, 2004, tsunami demonstrated that, no matter how rare they may be, when a major tsunami occurs, it could be very disastrous. The most basic information in tsunami warning center requires are charts showing tsunami travel times to various locations around the rim of the ocean. With this in mind, a tsunami travel time atlas for the Atlantic Ocean is in preparation. The Caribbean Sea is also included in this Atlas, as it is more or less a part of the Atlantic Basin.     

Is climate change impacting Rideau Canal Skateway,the world’s longest skating rink?

Natural Hazards - When disaster occurs in coal mines, the complex network structure of roadways and the disaster evolution process usually cause serious casualties. An efficient escape plan becomes...