Monthly Archives: March 2017

The World’s Worst Floods By Death Toll

The World’s Worst Floods
The Deadliest Floods As Measured By Death Toll
The World’s Worst Floods
The Deadliest Floods As Measured By Death Toll

Throughout history, floods have proven to be the deadliest natural disasters. This is mainly due to the high population densities around rivers. When well-behaved, rivers provide the resources needed for agriculture, transportation, and industry. It is no accident that all of the ancient civilizations rose around rivers.

It also should be noted that not all of the dead were the victims of the initial floodwaters. Disease and famine that followed the disasters probably killed more than the floodwaters themselves.

Flooding disasters primarily as a result of typhoons or hurricanes have been excluded from this list and are instead included on the list of worst hurricane disasters.

Huang He (Yellow) River, China
Death Toll: 1,000,000 to 3,700,000

The Huang He River is prone to flooding because of the broad expanse of plain that lies around it. One of the major reasons for the flooding is the high silt content that gives the river its yellow tint (and thus its name). The silt—which constitutes as much as 60% of its volume—builds up until the river actually is higher than the surrounding land. The tendency to flood is exacerbated by ice dams which block the river in Mongolia; the dams back up the water, and then release devastating walls of water when they break.

The history of flooding has prompted the Communist Chinese government to embark on a program of building dams for flood control. The dams, however, have not proven entirely effective and have been the target of criticism from environmentalists.

Huang He (Yellow) River, China
Death Toll: 900,000 to 2,000,000

Huang He (Yellow) River, China
Death Toll: 500,000 – 900,000

The 1938 flood of the Huang He was caused by Nationalist Chinese troops under Chiang Kai-Shek when they broke the levees in an attempt to turn back advancing Japanese troops. The strategy was partly successful. By 1940, the Japanese were essentially in a stalemate with Chinese forces.

Huang He (Yellow) River, China
Death Toll: 300,000

Chinese rebels destroy the dikes along the city of Kaifeng, flooding the surrounding countryside.

Ru River, Banqiao Dam, China
Death Toll: 230,000

This flood was caused by the collapse of the Banquia Dam, along with several others, following a heavy rain caused by a typhoon. It is the worst dam related collapse in history.

Yangtze River, China
Death Toll: 145,000

Although the Huang He has caused more deaths, the Yangtze has had more than 1,000 recorded floods.

The Netherlands and England
Death Toll: 100,000

A combination of high tides and storms flooded the Thames and the Netherlands, killing 100,000.

The Netherlands
Death Toll: 50,000

A seawall on the Zuider Zee failed, flooding the low-lying polder.

The Neva River, Russia
Death Toll: 10,000

An ice dam clogged the Neva, flooding nearby cities.

The Netherlands
Death Toll: 10,000

The failure of a seawall on the Zuider Zee flooded the Dutch lowlands.

Originally posted 2015-01-05 02:20:22.

Understanding The Richter Scale

The Richter Scale

The now-famous Richter scale was developed in 1935 by Charles Richter of the California Institute of Technology. The scale was intended only for use in California to separate the large number of small earthquakes from the small number of larger ones. The scale is derived from astronomy’s stellar magnitude scale.

The scale assigns a number to quantify the size of the earthquake. The number is derived by calculating the logarithm of the combined horizontal amplitude of the largest displacement from zero on a seismogram. It is a logarithmic scale, so an earthquake of five is ten times greater than a four, and an eight is 10,000 times greater than a four.

The energy of the earthquake is proportional to the square root of the cube of the amplitude. So each step of of the scale has an energy 31.6 times that of the previous. A nine, therefore, has 10,000 times the amplitude of a five, but a million times more energy.

Originally posted 2015-01-05 02:18:28.