There is no physical container at the cache site as this is an EarthCache!
Do not attempt this cache at night! Observations should always be done during the day with optimal lighting.
Please be respectful of the area and it’s residents, big or small!
Always practice CITO!
In order to log this EarthCache as found, you must answer the questions below and submit the answers to me via Geocaching.com's messaging feature, or through email.
For this EarthCache, we will be observing the cliffs of Shelter Cove and the effects that the San Andreas Fault could have on them.
The San Andreas Fault and Shelter Cove
The location of the San Andreas fault in the Shelter Cove area of Northern California has been the subject of a long debate within the geological community, even though surface ruptures were reported near Shelter Cove in 1906 during the earthquake that devastated San Francisco. Several subsequent geologists have questioned whether these ruptures represented a true fault slip or simply shaking causing the gravity driven deformations found in the area. After all, another fault is located offshore of Shelter Cove. That being said, most of the length of the San Andreas fault is on land, but much of it can be found off shore, north of Point Arena. A straight line can be drawn from its location offshore to the north, directly intersecting Shelter Cove and it's cliffed coasts, giving credence to this hypothesis.
This hypothesis is still unproven, yet compelling. A diagram of the hypothesized length of the San Andreas fault can be found in the gallery.
Faults
Massive faults within Earth's crust form by the action of plate tectonics, with the most massive forming the boundaries between plates, like subduction zones. Energy release associated with rapid movement on active faults is the cause of most earthquakes, including the San Andreas fault. The San Andreas fault is know as a lateral strike-slip fault.
Cliffed Coasts
A cliffed coast is a type of coast where the erosion from ocean waves has formed steep cliffs. This is in contrast with a flat or alluvial coast. On a rocky cliffed coast wave action is not the only force that drives coastline retreat. General weathering and erosion of the bedrock is just as important.
Mass Wasting
Mass wasting is the geologic process in which soil, sand, regolith, and other forms of rock move down a slope, usually as a solid, continuous or in-continuous mass, mostly under the force of gravity, but frequently with characteristics of a flow as in debris flows and mudflows. In extremely large instances of mass wasting, the rocks and other sediments can look as if they flow like water.
Scree
Scree is a collection or pile of broken rock fragments of varying sizes at the base of a cliff or other steep rock face that has built up through periods of rockfalls.
LOGGING REQUIREMENTS:
Please answer the following questions, to your best ability, using the information above. When you feel you have them answered correctly, send me your answers via the Geocaching websites messaging feature, or through email. Any "Found It" logs without the requirements being sent in, will be deleted.
Please include the GC code of this cache and the number of people in your party in your message.
1) Observe the cliffs along the beach. About how tall are they?
2) If the hypothesis above is correct and the San Andreas Fault actually does dissect this cliff, and an earthquake occurred, do you think any mass wasting would result?
3) Are there currently any signs of mass wasting along this cliff? If so, what are they?
4) This IS a requirement!
Please post or send me a photo of yourself or a personal object as proof you were at the site. Your face does not have to be included within the picture.
I hope you enjoyed this EarthCache, and most of all, I hope you learned something new!
Sources: Wiki, geology.com, britannica.com, Nationalgeographic.org, geoscienceworld.org, Personal Knowledge of Earth Science and Geology
CAA4JN