A) The epicenter is calculated after the all the aftershocks of an earthquake are plotted. It is the statistical center of the earthquake. The focus is the spot of first motion of the rocks.
B) The epicenter is where the energy is first released and the focus of the earthquake is where most of the damage is done
C) The focus of the earthquake is were surface waves are first detected while the epicenter is where the P and S waves are detected.
D) The epicenter is the spot on the Earth’s surface directly above the focus.

Comments (1)

Many powerful earthquakes are followed later by less-powerful earthquakes called “aftershocks.”
If an earthquake measures 6 on the Richter scale and is followed by an aftershock that measures 4, how
many times more energy was released in the original earthquake as compared to the aftershock?

Comments (1)

A 5.2 earthquake hit in a neighboring state one night with aftershocks felt in Indiana where I live.while I was sleeping it jarred me out of bed and I now wakeup occasionally in the middle of the night feeling what can best described as "phantom earthquakes." I checked the Earthquake website [http://earthquake.usgs.gov/earthquakes/] and there is nothing that validates my slumberous tremors. (SIDENOTE: Although I just updated 10 minutes later and surprisingly there was a 6.4 in Russia– but I find that somewhat besides the point.)

I don’t necessarily have a fear of earthquakes. Ever since the one we had felt it has caused me to wake up several times in the middle of the night feeling like there was a trembling occurring, none of which have been confirmed on the above website.

I have Googled my heart’s desire to find out if this is a legit thing I’m experiencing…phantom quakes. Any help and serious answerers would be helpful! Thanks.

Comments (2)

i know southern cali haas been having a lot of earthquakes(5.4 yesterday+ tons of aftershocks or something) not to mention mexicali earthquake and the easter earthquake were pretty large i read.
where do u think the next one will be?
if u think south cali, where abouts? theres a lot of south cali
well, not saying i believe in earthquake prediction, but u got to have some common sense. just a guess maybe

Comments (7)

are aftershocks good or bad

Comments (1)

I live only 15 minutes away from the Mexicali border where the 7.2 and other earthquakes have been propagated from and I tell you, i’ve been through the other quakes from 79 when I was a tot, on up and I have never felt one as violent as this one. I think the reason for such a violent earthquake was that it was shallow. I remember right after I was thinking "Christ, did that come from San Andreas??" I wanted to get on the roof to see where the or if there is a dust cloud to see. I lost a display hutch, a fire place mantel, and bottles and glasses. I also have new cracks around my house walls. I’ve seen pictures of Mexicali, man, they got whacked good, lots of liquefaction and collapsed buildings. Anyways, does anyone know of a site that has animations of the sort showing what actually moves underneath, besides the fault. I mean, what do the focus points look like where the epicenters are? I have been following the quakes since 2007, keeping my eye on that Serro Prieto mountain and the Laguna Sulada fault, I am concerned that it could trigger another large one on our side or even the Serro Prieto fault since the two rub elbows with each other. The Laguna Sulada butts right up against the Yuha Wells fault but I’m not sure if it is underneath or on top, lots of aftershocks have been coming from that area and are very close to the surface. Earthquakes fascinate me as well as they terrify me yup
Thanks but i know all about the fault and tectonic plates movement, the obvious, my 5 year old can explain that one, but I want to know more in detail

Comments (2)

If you haven’t heard, there was an earthquake in China with a 6.9 magnitude.
There were reported three aftershocks recorded at 5.3, 5.2, and 5.8 (according to USGS).

Let’s hope that the majority of the ones stuck under rubble will be able to be saved.

Let’s pray for their safety too.
What do you think of this drastic earthquake?
Spyro: Are you saying that 67 people dead isn’t enough to recognize a catastrophe? Besides the 67 dead, there are countless stuck under rubble. Even if you don’t believe in God, you could show some respect for the people that have died.

Comments (15)

Based on all the large earthquakes hitting the news.

Have there been more big earthquakes lately or are they just being shown on the news more often?
Not aftershocks.

Comments (3)

because the earthquake in baja , california that happened on april 4th 2010 is still having aftershocks here are some links i just wanna know is this normal?

http://earthquake.usgs.gov/earthquakes/recenteqsus/Maps/US2/31.33.-116.-114.php

http://latimesblogs.latimes.com/lanow/2010/04/500-aftershocks-and-counting-from-mexicali-earthquake.html

Comments (3)

Here is a quote from an article regarding the quake in Italy (L’Aquilla).

"The U.S. Geological Survey said the big quake was magnitude 6.3, but Italy’s National Institute of Geophysics put it at 5.8 and more than a dozen aftershocks followed."

I know that the Richter scale is logarithmic, so this difference is actually substantial. Do estimates normally vary this much?
Are you saying that it is different because one measurement was made on the N. American plate and the other made on the European plate?

Comments (2)