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Forensic Seismology

A cache by Jim Reeb Send Message to Owner Message this owner
Hidden : 10/26/2004
Difficulty:
4 out of 5
Terrain:
1.5 out of 5

Size: Size: small (small)

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Geocache Description:

An early morning Geocacher in northern Douglas County was startled by a bright flash and explosion. A meteorite had fallen.


Three seismic recording stations recorded the fall. You are the technician assigned to discover where the fall occurred and to recover the meteorite. You have gathered the following information:

Different types of seismic waves tend to move at different velocities. The fastest wave is the primary wave, or compressional wave, which is followed in time by the slower secondary wave, or shear wave. They are affected similarly by the materials they cross. As a result, there are relatively constant ratios between the velocities of different pairs of seismic wave types, no matter what kind of material they are passing through. P waves generally travel between 5.95 and 6.75 kilometers per second in the crust, depending on compressibility, rigidity, uniformity, and density of the materials traversed. S waves tend to move at velocities between 2.9 and 4.0 km/sec in the crust.

From previous information you know that P-Waves travel at 6.00 kps and S-Waves travel at 4.00 kps in the area of interest.

STATION LOCATION P-WAVE ARIVAL S-WAVE ARIVAL
GCG0M5 N39 30.840, W104 44.109 04:05:07.1673 04:05:07.4240
GCKPM8 N39 31.710, W104 47.901 04:05:07.2890 04:05:07.6065
GCJVMR N39 27.302, W104 46.119 04:05:07.5507 04:05:07.9990

Well, you are not allowed to actually take the fake meteorite but there is a container under it to log your find.

There are three Sacagawea coins, one for each of the first three teams to find the cache.

Unrealistic? Consider this: The plane impacts on the WTC towers were recorded several hundred kilometers away. When the towers collapsed, the impact of each floor hitting the one below it was recorded. When flight 93 crashed in rural Pennsylvania, seismology told the authorities that the plane was down and had crashed intact rather than exploding while in the air. There are 16,000 permanently installed stations around the world.

You can check your answers for this puzzle on Geochecker.com.

Additional Hints (Decrypt)


Uvagf: Akk kk.k03, Jlll ll.l95

Decryption Key

A|B|C|D|E|F|G|H|I|J|K|L|M
-------------------------
N|O|P|Q|R|S|T|U|V|W|X|Y|Z

(letter above equals below, and vice versa)



 

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Rendered From:Unknown
Coordinates are in the WGS84 datum

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