Talk:Epicenter
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How do the epicenters and hypocenters work?
Contents |
[edit] Epicenters and hypocenters
According to Merriam-Webster Online at [1], an epicenter is: 1:the part of the earth's surface directly above the focus of an earthquake.
According to Merriam-Webster Online at [2], a hypocenter is: 1:the focus of an earthquake; 2:the point on the earth's surface directly below the center of a nuclear bomb explosion.
However, I have seen many places which refer to the epicenter for an above ground explosion or some other news-worthy event. I have revised the text of this article to not mention above ground explosions, but feel free to revert if you disagree.--Astronaut 20:25, 10 Mar 2005 (UTC)
As I understand it, the term epicentre is used to refer to air-burst nuclear explosions in an analagous way to earthquakes i.e. hypocentre = where the bomb goes off, epicentre = point on ground vertically beneath hypocentre. I agree it needn't be in here though - needless complication IMO. —Preceding unsigned comment added by 138.253.112.241 (talk) 14:52, 19 September 2005
- No, Merriam-Webster is correct. It's the other way round: epicentre (or focus) = where the bomb goes off, hypocentre = point on ground vertically beneath epicentre. Astronaut 23:23, 10 August 2007 (UTC)
If "The epicenter or epicentre is the point on the Earth's surface that is directly above the hypocenter or focus" we need a (straight) line to follow in order to project the hypocenter onto the Earth's surface. Such line needs to be defined in the article. I suppose it is the line that passes through the Earth's geometrical center and the hypocenter, but I am not sure. (EPLeite 16:04, 1 December 2009 (UTC))
- I think the meaning of "above" is quite obvious and doesn't require further explanation. Astronaut (talk) 17:22, 1 December 2009 (UTC)
[edit] S-wave
Does not S-wave stand for secondary-wave and not shear-wave?
The P/S nomenclature may have originated as 'primary' and 'secondary', but if you were to ask a seismologist what they stood for he would say 'comPression' and 'Shear', simply because that is far more helpful in describing what they are.
[edit] Removed for clarification
Removed this recent addition:
- epicentral distance-it is the angle subtended at the center of the earth between the point of recording and the epicenter.it is normally represented by degrees and represented by Δ.
- Δ1 degree=110 kilometeres
- and Δ cannot be greater than 180 degree
as it needs serious rewriting if it is to be included. Vsmith 13:19, 19 August 2006 (UTC)
[edit] "Usage Panel"
The third paragraph as it presently stands expounds at length on the various opinions of "the Usage Panel". What is this panel and why are its opinions treated with such reverence as to include them in an encyclopaedia article? 62.25.106.209 17:19, 6 March 2007 (UTC)
- No idea; but whoever added this apparently ripped it off somewhere - it was removed as a copyvio. Astronaut 23:26, 10 August 2007 (UTC)
[edit] Merge proposal: Epicentral distance
[edit] epicenter and focus
epicenter is the point situated above the the focus it is the point on the surface of the earth from where the earthquake initiates the massive destruction takes place at the epicenter —Preceding unsigned comment added by 122.162.137.88 (talk) 04:02, 26 August 2008 (UTC)
[edit] Unit of "epicentral distance"?
Several references in Surface wave magnitude prints º as the unit for epicentral distance. This is neither a measure of distance nor one of time. What is the dimension of epicentral distance? This is particularly troublesome because without proper understanding of all related units and their reference values, definitions cited in these sources, even the original Richter formula are incoherent. Sillyvalley (talk) 07:06, 14 September 2008 (UTC)
- I think ° (note degree symbol, not º) is a perfectly valid measurement of epicentral distance - measuring the number of degrees between the measuring station and the epicentre. For example, an epicentral distance of 5° indicates the epicentre is approximately 556 km from the measuring station (calculated as follows: Earth circumference/360*5). Astronaut (talk) 15:55, 15 September 2008 (UTC)
- Thanks. This makes sense and needs to be added to the page - may need to find some citation, though. BTW, the Chinese site actually prints º - making things even more confusing. (The other paper is a scanned Image.) Sillyvalley (talk) 17:24, 15 September 2008 (UTC)
