Rockslide environs

Mission Peak Regional Preserve

(southeast of Fremont, south of Oakland, CA)

September 3, 2007


     

(Above) The lower rift, with the lower breakoff on the left (looking north)
(The aluminum tube, in the photos on this page, is 1.83 m [6'] long -- it was often much needed [with both hands], to traverse this terrain)
(Below) The cliff face left by the rockslide of March 22, 1998 (looking east), with the lower rift visible at top center
(hilltop elevation, about 564 m [1,850'])



(Above & below) View down the 1998 rockslide, from the bottom of the lower breakoff (looking west into Fremont)
The picture above looks across the Hayward Fault (maybe, a split from the San Andreas Fault, which is said to be about 30 million years old) -- this ridge of sandstone & other sedimentary rock may have been pushed up sideways by the Hayward Fault's movement



(Above) The lower rift (looking east), with the lower breakoff on the left
(Below) The lower rift (looking north), with the lower breakoff GPS receiver visible at the lower left, & the antenna of its connected power station at right


     

(Left) The fenced-off GPS receiver on the lower breakoff, connected by a conduit to (right) its solar power station, with a yagi antenna pointed to a USGS receiver in Menlo Park (looking north) -- in this picture, the GPS receiver is barely visible, near the left-hand edge of the hillside horizon


(Above) The upper rift, with the upper breakoff on the left (looking north)


(Above) The GPS receiver on the upper breakoff (looking west), connected by conduit to (below) the upper power station (looking south), which also has a GPS receiver, & another antenna pointed at Menlo Park



(Above) With the upper power station at right, the antenna of the lower power station is visible at left, just above the top fence wire (looking southwest) -- note the other rifts developing, there


(Above) Trees around the brook from Laurel Spring (looking south from the upper power station), with the Santa Cruz mountains in the background
(Below) Laurel Spring, and the woods below it
(Still flowing well, after no significant rain since spring, & a relatively dry winter -- maybe it has water ducted to it, through the rock strata, from the Mission Peak [elevation 767 m (2,517')] ridge, to its east)







http://en.wikipedia.org/wiki/Mission_Peak_Regional_Preserve#Geology

http://en.wikipedia.org/wiki/Image:Mission_peak_landslide.jpg

http://vulcan.wr.usgs.gov/Projects/ActiveLandslides/AGUPoster2000/LaHusenReid_AGUPoster2000.html

http://web.umr.edu/~rogersda/hazard_mitigation_techniques/landslides/fremont/MP.htm