Naked Science Forum

General Science => General Science => Topic started by: thedoc on 31/05/2016 20:50:01

Title: If enough people jumped at the same time could we cause an earthquake?
Post by: thedoc on 31/05/2016 20:50:01

John W Berger asked the Naked Scientists:
   Back in the 1960s, someone claimed that if the Chinese government wanted to destroy the USA, they could do it without firing a single shot. Instead, they calculated that if everybody in the country jumped from a height of 6 feet at the same time, the impact of a billion people hitting the ground simultaneously would send a shock wave through the earth and cause an earthquake in North America. And if that jump were repeated every hour, the shock wave would amplify.
Years later I heard a scientist had shown that such an event would not create the desired destruction but I've forgotten the reason behind it.
Does anyone at The Naked Scientists have an idea of why it will or won't work?
What do you think?

Title: Re: If enough people jumped at the same time could we cause an earthquake?
Post by: alancalverd on 31/05/2016 23:21:54

One person jumping creates an earthquake. But if the entire population of the planet stood shoulder to shoulder and jumped at once, the amplitude of the shock wave would be about 0.0000001 millimeter, or, in English, negligible compared with normal seismic activity. (Munroe, R: "What if?" (2014))

The US government is quite capable of destroying the country without the help of the Chinese government. Having narrowly failed to do so by deregulating the banking system and paying bankers for their incompetence, it seems they are now going to elect a complete oaf as president whilst attempting to impeach his opponent for not entrusting state secrets to the least secure email system of any modern adminstration (remember Snowden and Wikileaks?)

Par for the course, alas

Quote

In 1994, the economy had the lowest combination of unemployment and inflation in 25 years. As part of the 1993 Economic Plan, President Clinton cut taxes on 15 million low-income families and made tax cuts available to 90 percent of small businesses, while raising taxes on just 1.2 percent of the wealthiest taxpayers.

So what did Congress do? They impeached him for lying about a blow job, and replaced him with a drivelling idiot. If ever a nation had its head up its anus....