"Rules of the Road" while on Holy Sepulchre Cemetery Grounds
First I wish to thank the management of Catholic Church Oakland Diocese and Holy Sepulchre Cemetery for graciously granting permission to me to place this Earthcache on their property. You are more than welcome to visit and log this EC from their property, but they have asked me to let cachers know the following rules of behavior are require while on cemetery grounds (with the exception of the first these are their standard rules for vendors and contractors):
- No physical cache containers may be placed on this property.
- Sexual Harassment or Discrimination against any employee, customer, or other visitor.
- Stealing, removing or defacing property.
- Violation of safety rules or any form of unsafe behavior.
- Use of illegal drugs or alcohol on the premises.
- Cursing, fighting, threatening or disrupting employees, clients, or other visitors.
- Willful or careless destruction or damage, or improper use of property or assets.
- Solicitation or distribution of materials not related to the conducting of business.
Generally I know my cacher community, and we're a pretty well behaved lot. One other request on my part, please don't jump the fence onto the adjoining property.
For now this is the last in the series. I have my eye on a Strawberry Creek offset cache on the UC Berkeley campus, but I fear the bureaucracy and am not holding my breath about permission ever being given for that one.
About this Earthcache
If you got to GZ and look at a compass bearing of roughly 120 degrees (east by southeast) you will see a gully coming down the hill. You will notice that the upper portion of the gully is offset to the right relative to the lower part of the gully. This offset is associated with the "right-lateral strike slip" movement along the Hayward Fault. "Right-lateral" means that if your standing on one side of the fault facing the other side, the other side moves right relative to the side you are on. "Strike-Slip", let me break that down. In geology the strike is the compass bearing of a line created where a bedding plane, fault, or other planar feature intersects the horizontal. So, strike-slip is a fault with primarily horizontal movement.
Now you'll notice that in the middle of the offset you cannot see horizontal portion of the stream (where the fault is) because of the mass of vegetation growth, very uncharacteristic of elsewhere on the hill. The reason for the abundant growth is fresh water springs that occur due to the upwelling of groundwater caused by the fault. The grinding of the fault creates a zone of fine crushed rock called fault gouge. Fault gouge lacks the natural permeability of the surrounding rock. This low permeability gouge acts like a dam in a stream, causing the groundwater to backup behind it until it can spill over the top. That "top" is the ground surface and spilling over the top is a spring where water discharges to the ground surface. So all that vegetation you see is being "watered" by natural springs as a direct result of the fault. During the dry season when most of the grass is dry and brown, you can see linear sections of green grass on the hill due to the same natural springs.
About the Hayward Fault Series: This EC is first (from south to north) of a larger series of ECs all focusing on features of the Hayward Fault [this series is currently under construction, but individual ECs are being released sequentially to allow the largest number of cachers an opportunity for a FTF]. There is a final cache in the series (TBD) that can only be logged once you visited all the others in the series. Also, if you're interested in logging the final it is recommended you check out final in advance since observations you've made at this cache and other caches in the series will be helpful/required to log the final. Each of the ECs in the series contains slightly different information regarding the fault, with some overlap. Please see the Geotour for more information on this series (To be established).
About the Hayward Fault in General: The Hayward Fault is a splay off a the Calaveras Fault in the vicinity of San Jose, and the Calaveras Fault originates off the San Andreas Fault at a bend in the vicinity of Hollister (Figure of faults in the Bay Area http://i41.servimg.com/u/f41/16/31/61/01/haywar10.jpg ). The Hayward Fault starts in the vicinity of east of San Jose and extends at the foot of the East Bay Hills until disappears under San Pablo Bay at Point Pinole. The Hayward Fault is what is referred to as a right lateral strike-slip fault; this means that if standing on one side of the fault facing the other side of the fault, the opposite moves laterally (horizontally) to the right of the side your standing on.
Logging this Earthcache: As with all earthcaches you must answer a few questions, you will send these answers to me the cache owner. Feel free to log the cache at the same time you send me your answers. You will only here from me if you fail to send me the answers or I doubt that you actually went to the location. In your email please include the following:
1) The Name of the Cache
2) The toe of the slope is where you see the dramatic change in slope, about where the eastern fence is. What is the elevation of the stream offset above the toe of the slope?
3) Just eyeballing it, about how many feet is the upper and lower portions of the stream gully offset?