+- Earthwaves Earth Sciences Forum (http://www.earthwaves.org/forum)
+-- Forum: Earthwaves (http://www.earthwaves.org/forum/forumdisplay.php?fid=16)
+--- Forum: Q&A (http://www.earthwaves.org/forum/forumdisplay.php?fid=20)
+--- Thread: A puzzle in the Philippines (/showthread.php?tid=322)
A puzzle in the Philippines - Duffy - 10-25-2015
Hi all,
This is more a query than a question ....... An earthquake of 5.8 magnitude occurred on 19th Oct near Balitoc, Philippines, at a depth of 106 km. The USGS have classed it as significant on their "Earthquake hazards program" site. I was curious to know if anybody knew the nature of its significance ?.
Duffy,
RE: A puzzle in the Philippines - Skywise - 10-27-2015
(10-25-2015, 10:31 PM)Duffy Wrote: Hi all,
This is more a query than a question ....... An earthquake of 5.8 magnitude occurred on 19th Oct near Balitoc, Philippines, at a depth of 106 km. The USGS have classed it as significant on their "Earthquake hazards program" site. I was curious to know if anybody knew the nature of its significance ?.
Duffy,
I think that's just a loose description meaning the quake had an effect on the location... damage, injuries, etc....
There are defined adjectives depending on the magnitude, but "significant" is not among them.
8+ great
7+ major
6+ strong
5+ moderate
4+ minor
3+ light
Brian
RE: A puzzle in the Philippines - Island Chris - 10-28-2015
(10-27-2015, 06:39 PM)Skywise Wrote: I was traveling for work and my laptop or this site does not bring up my password when I am traveling, and I did not write it down in my new notebook (I probably have it). So, I did not post on hurricane Patricia. The USGS NEIC page posts M2.5 and higher for USA and M4.5 and higher for the world. But it will also post what it calls "significant", like a M3 in England (for example),, because that would be somewhat unusual and noticed.
Chris
RE: A puzzle in the Philippines - Duffy - 10-28-2015
Thanks for your responses guy's, appreciated ,,,, Unfortunately, I think the actual posting Its self may not have been intended for listing under "Significant Earthquakes......last 30 days", as I have recently checked the USGS 2015 archive and it isn't listed , I could be wrong but all the other quakes are there !!.
I'm sorry the question seemed irelevant considering the magnitude, but I'd noted in resent weeks there had been a couple of 5.9's at 10 kms deep and wanted to understand how a 5.8 at 106 km deep could supersede them !
Duffy,
RE: A puzzle in the Philippines - Duffy - 10-28-2015
(10-28-2015, 09:23 PM)Duffy Wrote: Thanks for your responses guy's, appreciated ,,,, Unfortunately, I think the actual posting Its self may not have been intended for listing under "Significant Earthquakes......last 30 days", as I have recently checked the USGS 2015 archive and it isn't listed , I could be wrong but all the other quakes are there !!.
I'm sorry the question seemed irelevant considering the magnitude, but I'd noted in resent weeks there had been a couple of 5.9's at 10 kms deep and wanted to understand how a 5.8 at 106 km deep could supersede them !
Duffy,
A 5.8 just occurred off the Solomon Islands, Talk about irony
Duffy
RE: A puzzle in the Philippines - Skywise - 10-30-2015
(10-28-2015, 09:23 PM)Duffy Wrote: Thanks for your responses guy's, appreciated ,,,, Unfortunately, I think the actual posting Its self may not have been intended for listing under "Significant Earthquakes......last 30 days", as I have recently checked the USGS 2015 archive and it isn't listed , I could be wrong but all the other quakes are there !!.
Many times events are updated as new information arrives and is analyzed. Sometimes when there is a larger quake somewhere the automated systems may get confused and put phantom quakes in odd places. Those get deleted later when a human looks at the data. Most quakes you see on the map, especially new ones, are automatically plotted by computers and the algorithms aren't perfect.
(10-28-2015, 09:23 PM)Duffy Wrote: I'm sorry the question seemed irelevant considering the magnitude, but I'd noted in resent weeks there had been a couple of 5.9's at 10 kms deep and wanted to understand how a 5.8 at 106 km deep could supersede them !
Location. Location. Location. A 5.9 under LA (or London!) would be very significant. A 5.9 out in the middle of the ocean doesn't get much attention other than being logged. Perhaps a better example magnitude might be a 4.0. In a place with good building codes like California or Japan, it gets noted in the local news but that's about it. In a 3rd world country where homes are made of mud brick, it can be devastating.
A note about depth. That "10km" you see is almost certainly a 'placeholder' depth. Depth is harder to determine than lat/lon, so the automatic solution may just use 10km as a temporary number unless it has enough data. And when more data arrives and is checked, the depth gets updated with a more accurate value.
Sometimes these updates can take a few days. The USGS folks do take the weekends and holidays off, and unless the quake is 'significant' it won't get checked until Monday. Sometimes they don't even show in the listings until then, or in the case of phantoms, get removed.
Brian
RE: A puzzle in the Philippines - Duffy - 10-31-2015
(10-30-2015, 09:43 PM)Skywise Wrote:Amazing how much you take at face value, when your unaware of how the data is actually compiled. Thanks Brian, that's been really helpful.(10-28-2015, 09:23 PM)Duffy Wrote: Thanks for your responses guy's, appreciated ,,,, Unfortunately, I think the actual posting Its self may not have been intended for listing under "Significant Earthquakes......last 30 days", as I have recently checked the USGS 2015 archive and it isn't listed , I could be wrong but all the other quakes are there !!.
Many times events are updated as new information arrives and is analyzed. Sometimes when there is a larger quake somewhere the automated systems may get confused and put phantom quakes in odd places. Those get deleted later when a human looks at the data. Most quakes you see on the map, especially new ones, are automatically plotted by computers and the algorithms aren't perfect.
(10-28-2015, 09:23 PM)Duffy Wrote: I'm sorry the question seemed irelevant considering the magnitude, but I'd noted in resent weeks there had been a couple of 5.9's at 10 kms deep and wanted to understand how a 5.8 at 106 km deep could supersede them !
Location. Location. Location. A 5.9 under LA (or London!) would be very significant. A 5.9 out in the middle of the ocean doesn't get much attention other than being logged. Perhaps a better example magnitude might be a 4.0. In a place with good building codes like California or Japan, it gets noted in the local news but that's about it. In a 3rd world country where homes are made of mud brick, it can be devastating.
A note about depth. That "10km" you see is almost certainly a 'placeholder' depth. Depth is harder to determine than lat/lon, so the automatic solution may just use 10km as a temporary number unless it has enough data. And when more data arrives and is checked, the depth gets updated with a more accurate value.
Sometimes these updates can take a few days. The USGS folks do take the weekends and holidays off, and unless the quake is 'significant' it won't get checked until Monday. Sometimes they don't even show in the listings until then, or in the case of phantoms, get removed.
Brian
Duffy,