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6.2 Arica

Posted: Thu May 06, 2010 1:38 am
by greg~judy
Earthquake Details
Magnitude 6.2
Wednesday, May 05, 2010 at 10:42:47 PM at epicenter
18.023°S, 70.533°W
35 km (21.7 miles) set by location program
30 km (20 miles) W of Tacna, Peru
55 km (35 miles) NNW of Arica, Tarapaca, Chile
A nice shake-up...
about 2245 here in Arica
strong enough to make g~j wonder :shock:
how long it would continue :?
how much stronger it might get :?
Not to worry... :)
Lights stayed on :)
Couple of weak aftershocks... within 15 min. 8)
wifi stopped for about 90 min. :(
Wondering if we were on the fringe
- of another bigger one down south :?:

Like the Doobie Bro's song...
Livin' on the Fault Line
Underneath us all
There's a world that we always forget 'til it moves us
Where the moon on the bay dances all alone

Ramone, he draw the razor swift, it slice the air
No more lovely dreams of those summer nights
Down in santo domingo
They laugh and play in the sleepy harbor town
So unaware of the danger that's around

Livin' on the fault line
Livin' on the fault line
Livin' on the fault line
Livin' on the fault line

No one can run when it finally comes down
Nobody knows what is stirrin' underground

Caruso stumbled
While the city tumbled down
The palace was in splinters
Theodore was leaving town

Re: 6.2 Arica

Posted: Thu May 06, 2010 6:23 pm
by greg~judy
No one else in the north felt this :?:
The Peruvian department of Tacna, bordering with Chile, is on alert after a strong earthquake measuring 6.5 on Ricther scale, the region's governor Hugo Ordonez said on Thursday.

The earthquake shook the region on Wednesday night, and on Thursday Ordonez said that after the first evaluation there were not reports of victims, however as a preventive measure they decided to suspend the school activities for 24 hours in the department.

Ordonez said that some electricity and telephone posts felt down, so there were blackouts and cut of the telecommunications for about two hours in Tacna city.

Ordonez said that there are also being inspected landslides in the highways jointing Tecna's capital with Tarata and Candarave.

The Geophysics Institute of Peru (IGP) said that the epicenter was located 59 kilometers west to Tacna with a depth of 39km. The earthquake was also felt in Chile and Bolivia.

Ordonez said that his office is working on a project of Early Alarm System to detect earthquakes and tsunamis in time. The project will have an initial investment of 3 million nuevos soles (1 million U.S. dollars). , the region's governor Hugo Ordonez said on Thursday.

Re: 6.2 Arica

Posted: Thu May 06, 2010 7:35 pm
by eeuunikkeiexpat
Wimpy stuff after you've been through an 8+ or ++ a 6.9 and too numerous to count 5+ aftershocks.

Re: 6.2 Arica

Posted: Thu May 06, 2010 8:46 pm
by greg~judy
Wimpy stuff...
No doubt... :!:

g~j were 800km away in Patagonia when your 8.8 went off...
From what we felt, that was close enuff, TYVM :)

But now, g~j are trying, as amateur earth scientists, to extrapolate the subjective effects of the P and S waves related to intensity and distance from epicenters.
Every tremor produces different types of seismic waves which travel through rock with different velocities: the longitudinal P-waves (shock- or pressure waves), the transverse S-waves (both body waves) and several surface waves (Rayleigh and Love waves). The propagation velocity of the seismic waves ranges from approx. 3 km/s up to 13 km/s, depending on the density and elasticity of the medium. In the Earth's interior the shock- or P waves travel much faster than the S waves (approx. relation 1.7 : 1). The differences in travel time from the epicentre to the observatory are a measure of the distance and can be used to image both sources of quakes and structures within the Earth. Also the depth of the hypocenter can be computed roughly.

In solid rock P-waves travel at about 6 to 7 km per second; the velocity increases within the deep mantle to ~13 km/s. The velocity of S-waves ranges from 2–3 km/s in light sediments and 4–5 km/s in the Earth's crust up to 7 km/s in the deep mantle. As a consequence, the first waves of a distant earth quake arrive at an observatory via the Earth's mantle.

Rule of thumb: On the average, the kilometer distance to the earthquake is the number of seconds between the P and S wave times 8. Slight deviations are caused by inhomogenities of subsurface structure. By such analyses of seismograms the Earth's core was located in 1913 by Beno Gutenberg.
We only have our own (admittedly narrow) input so far...
g~j wonder if allchileans in Iquique felt this event...
Then, a subjective report will be appreciated to assist our theories :wink:
Please report...
- time of initial tremor
- length of tremor
- rate on fear factor of 1-->10
Sorry, if I knew how to do a fancy questionnaire like Rune...
I would make it easier for y'all
Whilst we await the valued input of any Northern Allchileans...
g~j will open another bottle of Gato...
hold our glasses tightly...
and wait for more aftershocks 8)

Re: 6.2 Arica

Posted: Thu May 06, 2010 9:17 pm
by Steph
Definitely felt it here in Iquique - first time I have actually felt the energy waves in the air... a little disarming at first. The length of the tremor was the longest I have felt, but I am sure those down south think this is nothing, so I won't go overboard with my sense of alarm ;). Plenty of shake rattle and roll, but no power or internet cut. We're pretty well set up not to suffer damage if we can avoid it anyway, but I definitely re-checked our emergency plan today.

Re: 6.2 Arica

Posted: Thu May 06, 2010 9:35 pm
by greg~judy
Thanx steph...
We're pretty well set up not to suffer damage if we can avoid it anyway, but I definitely re-checked our emergency plan today.
g~j too... :!:
Our house is rock solid...
But... we are only 1+ km. from the beach
And only 20m. elevation.
Two choices when the tsunami hits...
Grab the big paddle board and head west :splash:
Or jump on g~j's tandem bike...
and peddle our butts east :whizz:
But yer right...
g~j updated our emerg. plan :D

Re: 6.2 Arica

Posted: Thu May 06, 2010 9:51 pm
by Steph
we're pretty close to the beach (a few hundred metres if that), but relatively well elevated. According to the municipal map, we are on the very edge of the tsunami zone, so we figure we have 2 choices too, up to the second floor and hope for the best, or grab the 3 kids (aged 5, 6 and 8) and run up the hill... Was grateful that the internet wasn't down last night, checked shoa immediately, felt like forever for the event to come up, and frankly, i wasn't sure whether to believe them when they said no tsunami warning... but there were no sirens, so i bunked down with my kids and attempted to sleep...

Re: 6.2 Arica

Posted: Sat May 08, 2010 10:33 am
by Stoph
Steph - Can you post a link to shoa? I gather it's a place to check for emergency info re: earthquakes, tsunamis?
Here in Antofagasta some think we are overdue. I'd like to know where to check for accurate info.

Re: 6.2 Arica

Posted: Sat May 08, 2010 11:04 am
by Steph
Stoph, Shoa has the tusnami warnings for coastal chile, and the USGS is the best (as far as I know) for info on earthquakes.

Shoa: click on the button that says información de Tsunami...

USGS: ... merica.php

Re: 6.2 Arica

Posted: Sat May 08, 2010 11:52 am
by greg~judy
Thanx for that SHOA link Steph...
Looking at the Tsunami Flood Charts...
For Arica - looks like our house@20m elevation on the north end of town is OK :D
Looking at Iquique... a much different picture.
Looks like a major portion of the city could be inundated :shock:
Those living in cities along the coast might do well to take a look at these topos
i.e. where your residence is placed, with regards an extreme event...
And have your emergency routes/kits planned :?: