this is a question from Alex who asks what if a RoR magnitude 15 earthquake were to hit America at let's say New York City what about a RoR Zer or 25 well given that a magnitude 25 Quake would destroy the sun if one happened there it would certainly destroy New York City but we're getting ahead of ourselves the RoR scale which has technically been replaced by the moment magnitude scale measures the strength of an earthquake since we usually hear about earthquakes with ratings somewhere between 3 and 9 a lot of people probably think of 10
as the top of the scale and Z is the bottom in fact there is no top or bottom to the scale but even if 10 isn't the top of the scale it might as well be a magnitude 9 earthquake already measurably Alters the rotation of the earth the two magnitude 9 plus earthquakes this Century both altered the length of the day by a tiny but measurable fraction of a second in order to get to magnitude 10 you'd need a ruptured fault line 32,000 km long and a magnitude 11 Quake would require a fault that went
Halfway Around the World a magnitude 15 earthquake would be a million times more powerful than that and involve the release of enough energy to evaporate all the water on Earth though if that happened we could rest easy knowing the earthquake couldn't cause any tsunamis going a few steps further a magnitude 18 earthquake would release nearly 10 to the 32 Jew of energy which is roughly the gravitational binding energy of the earth to put it another way the Death Star caused a magnitude 18 earthquake on alderon you could in theory talk about a more powerful earthquake
on Earth but in practice all it would mean is that the expanding cloud of space debris would be faster and hotter the sun with its higher gravitational binding energy could have up to a magnitude 24 Quake this is about the energy release you would get if you packed the entire volume of Jupiter with hydrogen bombs and detonated them all at once the most powerful Quakes in the known universe which occur in superheavy neutron stars are about this magnitude a magnitude 25 Quake would explode the sun hold on we're spending a lot of time thinking about
things that are large and violent what about the bottom end of the scale is there such a thing as a magnitude zero earthquake yes in fact the scale goes all the way down past zero let's take a look at some low magnitude earthquakes with a description of what they would be like if they hit your house a magnitude one Quake releases the same energy as dropping a partially loaded cement truck from 10 m onto the street in front of your house a magnitude zero earthquake is equivalent to the Dallas Cowboys American football team running at
Full Tilt into the side of your neighbor's garage a magnitude negative 1 Quake is like a single American football player running into a tree in your yard a cat falling off a dresser would have a magnitude of -2 a cat knocking your cell phone off your nightstand would have a magnitude neg3 magnitude -4 is like a penny falling off of a dog magnitude-5 is a key press on an IBM modelm mechanical keyboard -6 is a key press on a lightweight keyboard -7 is a single feather fluttering to the ground A fine grain of sand falling
onto the pile at the bottom of a tiny hourglass would be a magnitude 8 quake and let's jump all the way down to magnitude -15 a drifting mode of dust coming to rest gently on a table sometimes it's nice not to destroy the world for a change [Music]
