Peru-Chile Could Experience Megathrust Quake as Six Quakes Over 6 Mag Strike Area

That USG/EMSC 5.1 is mb

Peru have 4.8ML
25/03/2014 09:38:26 -17.80 -70.81 67 Km 4.8 ML III Tacna II Moquegua, Arequipa

www.igp.gob.pe...

5.1mb = 674 TTNT energy released
4.8ML = 239 TTNT energy released
435 TTNT difference, equal to another 4.97ML on top of the 4.8ML
That is why magnitude and type are important, and why all networks need to give the ML.
Mw seems to be the accepted standard after M6 because ML goes fuzzy, well OK, but these are borderline each side of M5
where is the ML???
What use is comparing Mw with mb and ML all in the same series

As I have only published one graph for the Chile series so far outside of ATS, I think I will go back and alter them to reflect this, ie all in ML, it will give a truer picture. This would bring the Mainshock in the offshore Tarapaca series up to 7.0ML (IRIS calculation) GUC didn't give an ML for that first one.

muzzy
That USG/EMSC 5.1 is mb

Peru have 4.8ML
25/03/2014 09:38:26 -17.80 -70.81 67 Km 4.8 ML III Tacna II Moquegua, Arequipa

www.igp.gob.pe...

5.1mb = 674 TTNT energy released
4.8ML = 239 TTNT energy released
435 TTNT difference, equal to another 4.97ML on top of the 4.8ML
That is why magnitude and type are important, and why all networks need to give the ML.
Mw seems to be the accepted standard after M6 because ML goes fuzzy, well OK, but these are borderline each side of M5
where is the ML???
What use is comparing Mw with mb and ML all in the same series

As I have only published one graph for the Chile series so far outside of ATS, I think I will go back and alter them to reflect this, ie all in ML, it will give a truer picture. This would bring the Mainshock in the offshore Tarapaca series up to 7.0ML (IRIS calculation) GUC didn't give an ML for that first one.

edit on 03000000838314 by muzzy because: (no reason given)

Muzzy, I think the reason all networks don't give a ML (Local Magnitude/Richter scale) is because it gives poor values for data gathered by stations more than 600 kms (370 miles) from an epicenter.

Unless there is real-time sharing of all local seismic network data, observatories can only give reliable magnitudes from stations they have access to, which may be too far away to give a ML.

It's not convenient. I think USGS only uses ML for small quakes, approximately 3.5 and smaller.

ETA: Muzzy, I know you and PM had posted a while back about how you calculated your energy equivalents. Any idea where that is? I was just wondering how you work out TNT for ML values, since it measures wave amplitude, not energy.

reply to post by Olivine

You may be right about the distance of stations, GSRAS always have mb (and sometimes Ms). Maybe mb should be the default magnitude type, which it is for the big networks I believe. However the country of origin networks rarely use mb.
Just want standardization, either mb, or ML or even Ms would do (China and LDEO seem to be the only ones who convert to Ms on a regular basis)

that formula that Puterman found was from Geofon (GFZ).
you need an excel spreadsheet to make it work
=(10^(4.8+($B2*1.5))/4184)/10^6 where the B2 is cell with the magnitude number in it , ie 5.1

I just found this by Googling "earthquake magnitude conversion"
good for individual calculations, it uses the same formula
alabamaquake.com...

having read that, I need to show that the TTNT ER is "radiated energy released" not "seismic moment"
That page doesn't specify what type of magnitude it is talking about though.

This one does, specifically ML, and its the same formula.
www.convertalot.com...

this from a pdf regarding Taiwan quakes
as I mentioned a few pages back the calculations vary region to region, based on the geology.
mb = (0.66 ± 0.03) ML + (1.69 ± 0.17)
Ms = (1.03 ± 0.06) ML - (0.53 ± 0.36)
Ms = (1.46 ± 0.08) mb - (2.52 ± 0.43)
ML = (1.268 ± 0.094) mb - (0.604 ± 0.485)

that first one might be handy

if it is used to convert that Peruvian 4.8ML to mb using + instead of ± it comes out as 5.2mb, which is 0.1 more than USGS's 5.1mb, but ...... on the scientific page they have a margin of error of 0.071 anyway.

might be straying off topic here, but it is relevant overall.
Been over this for years, never found a solution.

Its perhaps unsolvable, during my google search I found a couple of pdfs from scientific workshops discussing this very matter, all ended " ....... further discussion is required", they never have come to an agreement. One was from the Balkans, they can't even establish a standard within one region there!.

reply to post by muzzy


Excellent post, Muzzy.
Chalk full of resources that I am bookmarking now.

It is a mess. There just doesn't seem to be one standard solution. The Balkan comment made me giggle.

[/thread topic hijack]

Experts analyzing this flood of data are worried the increased seismic activity could be a sign the region is about to experience its first devastating quake in 137 years. The last event, a magnitude-8.5 quake in 1877, killed thousands of people and created a deadly tsunami that reached Hawaii and Japan.

"It is very unusual activity and we are trying to find out what is causing it," said Mario Pardo, deputy head of the seismology center at the University of Chile.

www.nbcnews.com...

Ok, so I see I am not the only one concerned here about all this seismicity. Gee, that's comforting.

Ahh, but wait...lookie here:

"We usually get around 10 earthquakes per day in this area [many of them very small], but now we have been getting up to 100 per day," he told NBC News via telephone from the country's capital Tuesday.

Pardo told NBC News that seismologists are particularly concerned about this cluster of quakes because press reports following the 1877 event said there was a similar "swarm" of tremors beforehand.

So there is even a known precedent for foreshocks here. How about that. And they said I was crazy.

The moderate sized quakes have slowed down in northern Chile at the moment, however small magnitude 2-4 earthquakes are still popping every 20 minutes or so.

I'm sure most of the people following this thread have seen member lostbook's thread concerning the situation in Chile, but if not, here is the link.

It's terrific that the seismologists in Chile are being up front about their concerns. This quote from a Reuters article sums up the observations made in this thread by TrueAmerican and others.

"This is already unusual," said Mario Pardo, a director at the University of Chile's seismic center, on Tuesday. "There are too many aftershocks to be only associated with the 6.7 quake."

Keep vigilant.


Well, crap, lol. I didn't see your post, TA.

reply to post by Olivine


lol, yeah, it's ok. We were probably writing them at the same time.

But note that we were on this before the news reports, before the experts, and before anyone. We rule!

EDIT: and oh, btw Oli, they just got NNA back up like 5 minutes ago. So I can see Peru again. For the moment.

reply to post by muzzy

Muzzy, at the end of that list of major quakes in your post you have a 9.0 in 1963.

As you didn't comment especially on this 9.0 I'm guessing that you were unsurprised by its inclusion in the list. Perhaps it's just ignorance on my part but it sure surprised me. I only know of two 9.0 or bigger events in the 1960s -- Chile's 9.5 in 1960 and Alaska's 9.2 in 1964, with the next closed being an 8.7 in the Rat Islands (Alaska) in 1965. So, your post is the first time I've heard of a 9.0 in 1963 anywhere in the world. I was under the impression that the biggest quake in the world that year was an 8.5 (some refs have it as an 8.6) in the Kuril Islands. Simply put, I didn't know there was a quake anywhere near a 9.0 in the region of Peru/Chile in 1963.

If you could provide a link to the pdf you used for reference I'd really appreciate it. (I couldn't find it in Tavera's huge, 547-page catalogue, so if it's there, please point me to the page.) I'd like to find out as much as possible about this event according to that pdf's data -- ie, the one you referred to, then dig around see what data other sources have on it. Granted, there may be some discrepancies in magnitudes published by various agencies but a quake anywhere around a mag 9.0 surely should show up in other lists as at least a high mag 8.

Thanks in advance,

Mike

reply to post by TrueAmerican

I guess one of the reasons ATS members like yourself get onto stuff like this odd series of events so quickly and suggest things the official experts don't want to come out and say, is that you are not beholden to any govt's or organization's current policy on what may or may not be said. And you don't have to worry about upsetting the "top experts" who can make it hard for researchers/scientists to get their next funding allocation. The pecking order, in other words.

reply to post by Olivine

Re that quote you posted, especially this part: "There are too many aftershocks to be only associated with the 6.7 quake."

That's pretty much what we've been saying for days. These "aftershocks" are not following the norms that aftershocks should. A 6.7 followed by so many in the 6 range? It's just not typical for aftershock activity.

In other words, that person is saying that probably, most of those aftershocks are not aftershocks at all. At least, not by normal definition.

JustMike
I guess one of the reasons ATS members like yourself get onto stuff like this odd series of events so quickly and suggest things the official experts don't want to come out and say, is that you are not beholden to any govt's or organization's current policy on what may or may not be said.

Actually, I have information that there is no such policy, and that came directly from... from... well, I can't say, sorry. I will not divulge my sources. But it was specifically stated to me that USGS scientists are under no gag orders like this, because I asked one of them that exact, specific question. They really just laughed. Somewhere we need to strike the appropriate boundary between conspiracy theory paranoia, and real fact. And as a matter of fact that's why I got into studying quakes and volcanoes for myself- cause I was tired of undue speculation, rumor, misunderstanding, and utter idiocy.

reply to post by JustMike


here is that pdf ECat_hipocPeru page 93
It seems there was an error converting it to Excel CSV, an X went in the Depth column and the 9.0 went in the Mag column, in fact there was no magnitude shown for this event, the 9.0 was actually the depth of it.
ID, SOURCE, TIME, LAT, LONG, DEPTH, MAG
PE38799, ISC, 26/04/1963 05:37:30, -16.6, -73.7, X, 9.0

I did look twice myself, and checked with Utsu but he didn't have it, not even as M8
I should have looked 3 times!
Thanks for noticing, I had been converting that catalog to csv and then kml ready to do a Peru maps page months ago and hadn't checked it for errors yet. My mistake.

reply to post by TrueAmerican

Thanks for your response. I didn't refer to USGS or in any way target them, but all the same I'm glad to hear that they can be free and open without any official policies restricting them. I just have my doubts that the freedoms USGS staff enjoy exist everywhere. Frankly I was more concerned with what the situation may be in the Sth American region we're looking at, as it's the focus of this thread.

But whatever. I was just giving my opinion. No-one is obliged to agree with me. However, I try to avoid posting idiocies in serious threads like this one and also prefer to avoid paranoia, so I hope my own comments didn't fall into those categories or the other negative ones you noted.

What bugs me is if a megathrust quake should occur in this thread's region of interest, either in the very near future or somewhere further down the line, we will doubtless see threads (here and on other sites) where the OP will claim the huge quake was caused by HAARP or a secret nuclear blast -- or some other half-baked "theory". Now, that's idiocy at its finest, and the disturbing thing is that not only do those absurd "causes" for huge quakes have their followers, they often seem impervious to all attempts to make them see reason.

Pardo of the University of Chile is quoted as saying

"We usually get around 10 earthquakes per day in this area (many of them very small), but now we have been getting up to 100 per day," he told NBC News via telephone from the country's capital Tuesday."

Only on the 2nd day (by date) (1st 24hrs by elapsed time)
I'm not doing it by the day, rather by the elapsed time, in 12 or 24 hour periods, but I went back and did a count, using local time as Prado was probably talking in that sense. This is off GUC's own data.
numbers count

reply to post by TrueAmerican

Whats with the secret squirrels?
If they are not afraid of the bosses, why won't they let you divulge their name/s?If they have signed a non disclosure document then they shouldn't be talking to you.

reply to post by muzzy

Well Muzzy, I'm relieved. I'm no expert on quakes but I was pretty worried that such a big one had occurred and I couldn't recall it! So I hunted through databases and still couldn't find it. Very glad it was just a glitch.

I guess that's one advantage of posting stuff we're working on. Extra eyes can help to pick up things and then we go back and check it again.

At least in this case, removing that one event doesn't make a huge difference in average interval (from 1471 up to 1950). About 37 years versus the original 33 if I've hit the right buttons on my calculator.

Thanks for the pdf. Interesting reading. I'm puzzled by a few of those huge quakes, though. Okay, for ones a few hundred years back any data on aftershocks is going to be very patchy, but with those two in 1868 (on the same day), there doesn't seem to be much by way of aftershocks. And in 1950, by which time they're listing quakes even down in the mid-3 range, we get this 8.6 on March 7th, but the next quake in the list isn't until March 10 (no magnitude given), and it's not all that close by. It looks like that huge quake didn't produce any obvious aftershocks at all. At least, not in the short term. I just wonder about what effects it had, and how deep it was.

A last thought: those two on Aug 13, 1868. (A Thursday, in case anyone wonders, what with it being on a 13th!) They're physically far enough apart (about 230 km) and the time between them of 23 minutes suggests they were, indeed, separate events and not just duplicate reports of one. That's a heck of an energy release in a pretty localized region in such a short space of time. Be interesting to compute what the total energy release would be equivalent to.

4.7 just hit central Peru, moderately deep at 138 km depth:

www.emsc-csem.org...

USGS will probably have that at about 4.5, if they have it at all.

Maybe nothing, or could be linked somehow to all this other activity with the Nazca Plate. I report. You decide.

And muzzy, I am the one not wanting to divulge the sources- they have said nothing about it, usually. It's just better that way.

And JustMike, relax. That wasn't directed in any way at you personally. It was a general statement.

reply to post by TrueAmerican

It's all good, man. I didn't take it badly. Hence the thumbs up I gave you after I thanked you for your response, to show I meant my thanks genuinely. But yeah, there's an awful lot of idiocy around.

Regarding that Peru quake: USGS have posted it and have it as a 4.9 at the moment.

M 4.9 - 38km SSE of Pucallpa, Peru
DYFI? - III

Time
2014-03-27 18:59:12 UTC+01:00
Location
8.682°S 74.385°W
Depth
141.0km

All USGS quake data quoted in this post is available via the USGS world quake map HERE

I see there's also been a 5.5 and 5.4 SW of Vinchina in Argentina. Very close together geographically but 20 minutes apart, so does appear to be two separate events.

M 5.5 - 63km SW of Vinchina, Argentina
PAGER - GREENShakeMap - VIIDYFI? - IV

Time
2014-03-28 00:50:52 UTC+01:00
Location
29.130°S 68.708°W
Depth
9.9km

M 5.4 - 72km SW of Vinchina, Argentina
DYFI? - I

Time
2014-03-28 01:10:37 UTC+01:00
Location
29.186°S 68.776°W
Depth
13.4km

I just checked EMSC. They give the same mags as USGS on these two Argentinian events, and agree with the timing. So, two events.

JustMike
reply to post by TrueAmerican

 

Thanks for your response.

I didn't refer to USGS or in any way target them, but all the same I'm glad to hear that they can be free and open without any official policies restricting them. I just have my doubts that the freedoms USGS staff enjoy exist everywhere. Frankly I was more concerned with what the situation may be in the Sth American region we're looking at, as it's the focus of this thread.

But whatever. I was just giving my opinion. No-one is obliged to agree with me. However, I try to avoid posting idiocies in serious threads like this one and also prefer to avoid paranoia, so I hope my own comments didn't fall into those categories or the other negative ones you noted.

What bugs me is if a megathrust quake should occur in this thread's region of interest, either in the very near future or somewhere further down the line, we will doubtless see threads (here and on other sites) where the OP will claim the huge quake was caused by HAARP or a secret nuclear blast -- or some other half-baked "theory". Now, that's idiocy at its finest, and the disturbing thing is that not only do those absurd "causes" for huge quakes have their followers, they often seem impervious to all attempts to make them see reason.

There are many ways to cause an earthquake and many things that can cause an earthquake. You should not be calling it idiocy, when it is basic science. It does not mean an earthquake was caused by HAARP when an earthquake happens. Earthquakes happened before that existed. But it is scientific fact that there are numerous ways to artificially generate an earthquake.

People should not be called idiots for pointing that out.

There was quite a shift in the location of activity (aftershocks) after that 5.8Ml (6.3Mw) on the 22nd, while GUC may not have the correct location of the strong aftershock the activity thereafter definitely moved to the north.
The next one 6.1ML (6.2Mw) shifted the activity again, even more to the NE.
Each one of these strong aftershocks 5.7-6.1ML seems to have its own little aftershock series, very much like the Cook Strait 2 x 6's in July/Ag 2013, however these were happening on a daily basis, whereas the Cook Strait ones were almost a month apart , and in reverse order CS = 5.7, 5.8, 6.5, 6.6 versus TC=7.0, 5.9, 5.7, 5.8, 6.1 (ALL ML)
perhaps an opposite order for opposite sides of the Pacific Plate?
As time goes on, the more this looks like a classic Mainshock and Aftershock series.........
offshore Tarapaca, Chile, 16/03/2014, 7.0ML (6.7Mw) and aftershocks

I have recalibrated the graphs to ML too. A truer picture of what was happening I believe

(click image for larger version, opens in new tab/window)

muzzy

As time goes on, the more this looks like a classic Mainshock and Aftershock series.........

At this point I am inclined to agree, and could be that Peru-Chile just dodged a bullet. I have not one single regret starting this thread though, and I still think something could be amiss. So I will tentatively and cautiously back away. But when I see seismicity like this anywhere that appears to break the rules, "I'll be back" with my alarm bells.