What is Earthquake: Definition and 165 Discussions
An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in size from those that are so weak that they cannot be felt to those violent enough to propel objects and people into the air, and wreak destruction across entire cities. The seismicity, or seismic activity, of an area is the frequency, type, and size of earthquakes experienced over a period of time. The word tremor is also used for non-earthquake seismic rumbling.
At the Earth's surface, earthquakes manifest themselves by shaking and displacing or disrupting the ground. When the epicenter of a large earthquake is located offshore, the seabed may be displaced sufficiently to cause a tsunami. Earthquakes can also trigger landslides and occasionally, volcanic activity.
In its most general sense, the word earthquake is used to describe any seismic event—whether natural or caused by humans—that generates seismic waves. Earthquakes are caused mostly by rupture of geological faults but also by other events such as volcanic activity, landslides, mine blasts, and nuclear tests. An earthquake's point of initial rupture is called its hypocenter or focus. The epicenter is the point at ground level directly above the hypocenter.
Hello. I am doing a review sheet for my Pre-Calculus final and one of the questions has me stumped. I'm going through our notes and we never did a problem like this in class. Any help would be greatly appreciated. Thank you.
Find the Richter scale magnitude of an earthquake that releases energy...
They set a tsunami warning. Seems to be several.
http://geofon.gfz-potsdam.de/eqinfo/seismon/globmon.php
http://earthquake.usgs.gov/earthquakes/eventpage/us20007z8m#region-info
Quite recent, so updates will follow. Over the radio in NZ, it is said a tsunami warning has been issued.
Magnitude 7.3 at the moment, possibly be revised.
http://www.stuff.co.nz/world/asia/86723022/big-earthquake-near-japan
I know we have members who watch earthquakes and especially in that region.
http://www.bbc.com/news/world-asia-37967178
Potsdam and CNN even report 7.8 in 10 km depth. Tsunami warning set.
Does anybody know more?
Oklahoma has been experiencing numerous small earthquakes (Mag 3-4 range) in recent years.
A Mag 5.6 earthquake in Pawnee, Oklahoma happened this morning.
http://earthquaketrack.com/us-ok-broken-arrow/recent
2016-09-03 12:02:44 UTC
36.429°N 96.923°W
6.6 km depth
That's somewhat unusual...
M6.8 - 25km W of Chauk, Burma
2016-08-24 10:34:55 UTC 20.919°N 94.579°E
84.1 km depth
http://earthquake.usgs.gov/earthquakes/eventpage/us10006gbf#executive
Fairly deep though, but still pretty strong.
@davenn, did you get a signature?
USGS reports a Mag 6.2 earthquake near Norcia, Italy.
http://earthquake.usgs.gov/earthquakes/eventpage/us10006g7d#executive
http://earthquake.usgs.gov/earthquakes/eventpage/us10006g7d#region-info
https://www.yahoo.com/news/magnitude-6-4-quake-hits-italy-near-perugia-015222205.html
There were a...
San Francisco and Southern California is south of the Cascade region.
USGS has issued an Outlook for the region.
https://pubs.er.usgs.gov/publication/fs20163020
It relates to the San Andreas Fault and related faults down through southern California into Baja California in Mexico...
Hello PF
This seems to be the biggest threat for my country.
http://m.phys.org/news/2016-07-giant-quake-lurk-bangladesh.html
Could you please review and tell how much possibility is there for that earthquake to happpen?
Homework Statement
Here is the seismogram in question: http://postimg.org/image/iu0dozetn/
There are many parts to this question, but I only need help with this one: Measure the S wave arrival time.
Homework Equations
NA
3. Attempts at a Solution
I know that the P waves arrive at 40...
5.2-Magnitude Earthquake Rattles Southern California, Felt in Los Angeles, San Diego
https://gma.yahoo.com/5-2-magnitude-earthquake-rattles-southern-california-felt-112449426--abc-news-topstories.html
M5.2 - 20km NNW of Borrego Springs, CA...
Hi guys and gals
The Australian doesn't get too may quakes M5 and up. On average one every approx. 4-5 years
The latest occurred this morning, 04:14:02 EST, 21st May ( local time) recorded as a M 6.1 by
Geoscience Australia ( GA is the Australian Govt. Institute for monitoring such activity...
Homework Statement
The question is featured in the image below. I know the methods to calculate modal mass, stiffness etc, I'm just not too sure how to model both the distributed and lumped masses together.
Homework Equations
Modal Mass, M* = ∫m.φ^2(x) dx
The Attempt at a Solution
Say for...
There is some discrepancy on the magnitude.
USGS reports - M4.8 - 12km WNW of Masterton, New Zealand
http://earthquake.usgs.gov/earthquakes/eventpage/us20005h22#general
2016-04-11 19:41:06 (UTC)
Location: Lat 40.932°S, Long 175.514°E
Depth: 27.1 km (16.9 mi) - shallow. Folks in the vicinity...
Earthquake strikes remote region of Alaska
http://www.cnn.com/2016/04/02/americas/alaska-earthquake/index.html
M6.2 - 100km NNE of Chignik Lake, Alaska (Near Jaw Mountain)
http://earthquake.usgs.gov/earthquakes/eventpage/ak13226799#general_region
A swarm is also associated with this event...
The matter of large tsunamis come up in another thread on thermonuclear explosions. Very large earthquakes Mag 8 and greater, produce energies well above the largest manmade thermonuclear detonation. They can also create large tsunamis. The 1964 earthquake produced large tsunamis in Alaska...
I am doing business with a Japanese partner to help japanese people to remain safe during earthquakes which require building a small metallic shelter in their homes, it should stand the destruction during an earthquake.
My question, what metal is the right choice? :oldconfused:
It must have...
http://news.yahoo.com/6-4-magnitude-earthquake-strikes-southern-taiwan-210602384.html
Nearest major cities are Tainan and Kaohsiung.
http://earthquake.usgs.gov/earthquakes/eventpage/us20004y6h#general_region
Time: 2016-02-05 19:57:27 (UTC)
Distance from major cities:
28km (17mi) NE of...
http://news.yahoo.com/federal-agency-magnitude-6-4-earthquake-hit-southern-110243052.html
USGS reports 7.1
http://earthquake.usgs.gov/earthquakes/eventpage/us10004gqp#general_summary
Time
2016-01-24 10:30:30 UTC
Location
59.659°N 153.452°W
Depth
127.8 km - fairly deep though
In my story about a planet called Kepler Bb(B flat like in music). It has 4 moons and orbits around a double binary star. In the 11th chapter I have an whole sequence of earthquakes in the same area that lasts for hours. Then after the earthquakes stop somebody checks the fault line and it is...
Can someone please solve this . I have been trying to solve this from last 2 days.
1. Question
An earthquake with a magnitude of 5.4 is 39 times as intense as an aftershock that occurs five hours later. What is the magnitude of the aftershock? Round your answer to one decimal place.
2. Formula...
The New Yorker magazine of 20 July 2015 had an interesting article about the "Cascadia" subduction zone along the coast of N.Calif, Oregon, Washington, Br.Columbia
http://www.newyorker.com/magazine/2015/07/20/the-really-big-one
I looked up some background. Wikipedia seemed quite informative.
A...
Can some name easy understanding book related to earthquakes, seismic analysis so that non civil engineer or geologist etc can understand can this topic and seismic analysis basics.
Barely 2 weeks after the 7.8 magnitude earthquake which killed nearly 8000 people and injured more than 17,800 ,Nepal was struck by another 7.3 magnitude earthquake on May 12 local time 12:35 pm. Once again in the middle of the day, people were rambling out on the streets of the nation's capital...
In the Earth forum, there is a thread about the Nepal earthquakes which started with a mag 7.8 earthquake.
This thread is about the human impact.
More than 2,200 confirmed dead in Nepal earthquake
http://news.yahoo.com/aid-starts-coming-nepal-quake-kills-nearly-2-050207892.html
International...
This is the latest update from the USGS and affiliated institutions for California, USA, for the next 30 years..
see more at ...
http://www.usgs.gov/newsroom/article.asp?ID=4146&from=rss&utm_source=dlvr.it&utm_medium=facebook#.VRUfzU3EDxH
cheers
Dave
Hi, I found a great generator, Earthquake 800 watt inverter style that is quiet and runs 14 hours on a gallon. BUT the Bosch SDS drill kills the engine, even if you barely pull the trigger.
https://www.amazon.com/dp/B00FL89I2W/?tag=pfamazon01-20
I have a 750 watt inverter I hook up to 12V...
I came across an interesting video on three massive earthquakes and the thrusts that caused tsunamis.
Just because an earthquake is large, i.e., mag 7 or mag 8 or greater, and in the ocean doesn't mean it will produce a tsunami. It does depend on the depth and location as well, and how much...
They had one yesterday - 8.2 - http://www.bbc.co.uk/news/world-latin-america-26846984
And now another is reported: http://nz.news.yahoo.com/a/-/world/22350089/7-4-earthquake-strikes-chile/
I'm a total noob when it comes to geology, so sorry if this is a dumb question.
I live on the Ring of Fire so earthquakes are never far from my thoughts. I go to the USGS earthquake page often just to check out how our Earth is doing.
Lately I've notice a cluster of quakes just north of...
Scientists find near-definitive list for rare "earthquake lights"
Scientists find records of rare 'earthquake lights'
http://www.usatoday.com/story/news/nation/2014/01/02/earthquake-lights-rare-phenomenon/4255097/
Part 1 can be found here:
https://www.physicsforums.com/showthread.php?t=480200
Magnitude-5.3 earthquake hits Japan's Fukushima
http://www.usatoday.com/story/news/world/2013/09/19/japan-fukushima-nuclear-plant/2835493/
There's been an earthquake of about 4.7 on I don't know which scale less than 50 km away from where I live. I filled a questionnaire and there was the word askew in it, so I asked google what it means and... well try yourself. Put askew in google. :smile:
Here is your opportunity to weigh in on one of the Fukushima issues. First link is the study and second link discusses the comment process.
http://pbadupws.nrc.gov/docs/ML1313/ML13133A132.pdf
http://pbadupws.nrc.gov/docs/ML1317/ML13175A104.pdf
I don't know that this completely fits in the mech. eng. category but I figure this crowd would know as well as anyone.
so I like to spend my free time thinking about these kinds of things. I am always trying to come up with innovative solutions to problems.
here goes, I have seen the...
A large earthquake (7.8) has been reported on the border region in Iran near the border with Pakistan's Balochistan province.
http://earthquake.usgs.gov/earthquakes/eventpage/usb000g7x7#summary
This is coincident with a number of mag 5 and 6 earthquakes along the junction of the Australian...
6 scientists and a gov official in Italy are sentenced to 6years and 10million euro fine each for not predicting an earthquake...sounds like news that should be coming from places like Haiti.
http://edition.cnn.com/video/?hpt=hp_t4#/video/crime/2012/10/23/bw-italy-laquila-verdict.cnn
We don't have a forum for Civil Engineering, so I post this here and invite the moderator to move it if it better fits someplace else.
They had a very strong earthquake yesterday and today it is minor news because they had no deaths directly related to it and very little damage. One guy did...
The seismic waves of earthquake travels at around 5 km/s. Wouldn't it be possible to setup network of detectors through out the world, and pre-warn people about approaching earthquake in real-time?
http://www.yomiuri.co.jp/dy/national/T120209007089.htm "Fukushima No. 2 plant was 'near meltdown'"
http://ex-skf.blogspot.com/2012/01/japanese-expert-says-fukushima-ii-not-i.html "Just In: Japanese Expert Says Fukushima II (not I) Nuke Plant's Containment Vessel Has Been Damaged by the Quake"
We're approaching the bicentennial anniversary of the largest earthquake and swarm east of the Rocky Mountains, at least in recent history. Coincidentally, Oklahoma has just had it's largest earthquake in the state's history.
Bicentennial of the New Madrid Earthquake Sequence December...
Hello,
I want to write an earthquake simulation for one of my programming classes and wanted to know where to look to get started understanding some of the forces and other properties of earthquakes. This is for a video game physics class so it doesn't have to be super accurate the class is...
Hi there. So, I was wondering if there is anyway to tell what the perceived magnitude of today's earthquake is, based on my distance from the epicenter. I live around Princeton, so I was about 250 miles north of the epicenter. I was thinking that there might be an equation that describes how...