Chile Forum

Earthquake Details
Magnitude 6.2
Date-Time
Wednesday, May 05, 2010 at 10:42:47 PM at epicenter
Location
18.023°S, 70.533°W
Depth
35 km (21.7 miles) set by location program
Region
OFFSHORE TARAPACA, CHILE
Distances
30 km (20 miles) W of Tacna, Peru
55 km (35 miles) NNW of Arica, Tarapaca, Chile

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

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.

Wimpy stuff...

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're pretty well set up not to suffer damage if we can avoid it anyway, but I definitely re-checked our emergency plan today.