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I have been on earthquake alert lists for years and the trend I have noticed lately is that some of these earthquakes are being reported as occurring much deeper than the usual range. Last week the range was 0 - 60km deep; the 60km being unusual.
This week there has been one recorded at 81km deep in southern Alaska and the new depth range so far is 0 - 100km. I am including the 100km deep earthquake alert below.
I think this is a significant trend.
Sent: Mon 6/02/08 12:29 AM
== PRELIMINARY EARTHQUAKE REPORT ==
Region: ALASKA PENINSULA
Geographic coordinates: 58.672N, 156.644W
Magnitude: 3.3 Ml
Depth: 100 km
Universal Time (UTC): 2 Jun 2008 04:19:50
Time near the Epicenter: 1 Jun 2008 20:19:50
Local standard time in your area: 2 Jun 2008 04:19:50
Location with respect to nearby cities:
2 km (1 miles) SSE (155 degrees) of King Salmon, AK
20 km (13 miles) ESE (112 degrees) of Naknek, AK
22 km (14 miles) E (101 degrees) of South Naknek, AK
474 km (295 miles) WSW (237 degrees) of Anchorage, AK
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Interesting, Polly, but I have to admit to some ignorance about earthquakes.
Does a deeper quake have an impact on the severity of damage above ground?
What would you speculate about the cause of the deeper quakes? Changes in the Earth? Deeper tunneling by those that live underground?
Please keep us posted.
That's what my initial question was after I read your post.
"I think this is a significant trend."
Why?
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If you think about the earth's crust and then the upper mantle which lies beneath, these deeper earthquakes are occurring in the upper mantle. The crust is usually under 50 km deep. If the mantle is repeatedly shifting, the crust on top would be subject to eventual reactive adjustment, even more so it would seem than if the quake was still located in the crust. Does that make sense?
We hear about surface technology and space technology being used to enhance earthquake activity. Well, it causes me to wonder what is going on underground which is adding to the stress of earth movement.
Here is another alert which came through this afternoon. Again, this one is being reported at 100km deep.
Sent: Mon 6/02/08 4:03 PM
== PRELIMINARY EARTHQUAKE REPORT ==
***This event supersedes event AT00243539.
Region: CENTRAL ALASKA
Geographic coordinates: 63.596N, 149.524W
Magnitude: 4.3 Ml
Depth: 100 km
Universal Time (UTC): 2 Jun 2008 19:36:39
Time near the Epicenter: 2 Jun 2008 11:36:39
Local standard time in your area: 2 Jun 2008 19:36:39
Location with respect to nearby cities:
35 km (22 miles) W (260 degrees) of Denali National Park, AK
39 km (24 miles) NW (307 degrees) of Cantwell, AK
46 km (29 miles) SSW (205 degrees) of Healy, AK
163 km (101 miles) SSW (213 degrees) of Fairbanks, AK
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Yikes! Depth - 191km
Sent: Wed 6/04/08 1:30 PM
== PRELIMINARY EARTHQUAKE REPORT ==
Region: HOKKAIDO, JAPAN REGION
Geographic coordinates: 41.568N, 139.058E
Magnitude: 5.6 Mw
Depth: 191 km
Universal Time (UTC): 4 Jun 2008 17:03:05
Time near the Epicenter: 5 Jun 2008 02:03:05
Local standard time in your area: 4 Jun 2008 17:03:05
Location with respect to nearby cities:
141 km (88 miles) W (262 degrees) of Hakodate, Hokkaido, Japan
161 km (100 miles) WNW (301 degrees) of Aomori, Honshu, Japan
222 km (138 miles) NNW (337 degrees) of Akita, Honshu, Japan
659 km (410 miles) N (355 degrees) of TOKYO, Japan
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Holy cow! Polly, do you happen to know if there have ever been quakes this deep before?
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I don't recall any, GR. That is why I am making an issue of this trend now. I became used to seeing the same small range of depths of earthquakes over the years in the email alerts and then this trend began recently which stuck out for me.
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This earthquake was reported at 604km. I have been going by USGS's data as far as depth is concerned and my noticing that the depths of earthquakes has increased lately. There is often a difference in depth between USGS's data and EMSC's data but in this case they are close in the depth reported.
USGS data:
== PRELIMINARY EARTHQUAKE REPORT ==
***This event supersedes event AT00349239.
Region: FIJI REGION
Geographic coordinates: 17.761S, 179.659W
Magnitude: 5.7 Mb
Depth: 604 km
Universal Time (UTC): 15 Jun 2008 01:13:11
Time near the Epicenter: 15 Jun 2008 13:13:11
Local standard time in your area: 15 Jun 2008 01:13:11
Location with respect to nearby cities:
598 km (371 miles) NW (308 degrees) of NUKU'ALOFA, Tonga
3185 km (1979 miles) W (265 degrees) of PAPEETE, Tahiti, French Polynesia
ADDITIONAL EARTHQUAKE PARAMETERS
________________________________
event ID : US 2008thaf
EMSC data:
http://www.emsc-csem.org/index.php?page=home
Summary:
Magnitude
mb 5.6
Region
FIJI REGION
Date time
2008-06-15 at 01:13:10.9 UTC
Location
17.73 S ; 179.68 W
Depth
600 km
Distances
205 km E Suva (pop 199,455 ; local time 13:13 2008-06-15)
172 km SE Labasa (pop 33,397 ; local time 13:13 2008-06-15)
148 km SE Savusavu (pop 7,922 ; local time 13:13 2008-06-15)
What comes to mind is more deep, ugly goo from humanity's subconscious is surfacing for review. icon_escape
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[size="3"]hmmm, I wonder how these deeper quakes will affect the DUMB's?
perhaps [/size][size="3"]when TSHTF [/size][size="3"]the surface really will be a safer place to be?
Simon[/size]
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