Stevens Creek Main Branch above Waterwheel Creek, Initial Recon

A short hike upstream along Stevens Creek from the confluence of Waterwheel Creek.

I found I could get down into the creek channel between Branch D and Waterwheel Creek. Was able to get about 0.1 miles up the canyon before I ran out of time and had to turn back. From that point onward, the canyon appears to get more rugged with a series of landslides triggered by recent earthquakes.

I would like to return and explore more of the canyon once I do some exploring upstream. With recent rains, the water may be flowing again, so this may have to wait until next fall.

In GaiaGPS, you can download and install the bedrock geology layer and it's striking the difference in the rock types on either side of the San Andreas fault. One side of the canyon is all dark colored Mesozoic rocks of volcanic origin that were formed along island arcs that were pushed up onto the west edge of North America. The other side is light colored Miocene marine sedimentary rocks that were pushed up along the Southern California coast and then transported hundreds of miles north by the fault movement. Standing on the canyon here, those different rock types are right in front of you!

A nice find from the OsmAnd Wikipedia layer, not only does this area contain tectonic blocks, speleothems, but it's also the epicenter of a little known earthquake!

OsmAnd WIkipedia layer:
https://wiki.openstreetmap.org/wiki/OsmAnd#Strong_Wikipedia_Integration

1838 San Andreas earthquake:
https://en.wikipedia.org/wiki/1838_San_Andreas_earthquake
https://youtu.be/mDLw9tCSRSQ

Paleo-Seismic Evidence of the 1890 and 1838 Earthquakes on the Santa Cruz Mountains Section of the San Andreas Fault, near Corralitos, California:
https://pubs.geoscienceworld.org/ssa/bssa/article-abstract/104/1/285/331810/Paleoseismic-Evidence-of-the-1890-and-1838?redirectedFrom=fulltext

San Francisco's 1906 quake was third of a series on San Andreas Fault:
https://pages.uoregon.edu/digital/uonews-archive//archive/news-release/2014/2/san-franciscos-1906-quake-was-third-series-san-andreas-fault.html

Geologic Analysis Of The Monte Bello Ridge Mountain Study Area paper:
https://fbdroch.com/book/environmental-geologic-analysis-of-the-monte-bello-ridge-mountain-study-area-santa-clara-county-california

From that paper:
"TECTONIC BLOCKS - Large angular to rounded, commonly elliptically shaped masses of relatively hard rocks surrounded by a clay-rich, sheared matrix. Occurs within shear zones and fault gouge. In the shear zones of the Franciscan rocks, these blocks range from "fist size" to masses more than one mile long."

USGS National Map Viewer w/ Hill Shade:
https://apps.nationalmap.gov/viewer/

About the USGS HTMC:
https://www.usgs.gov/programs/national-geospatial-program/historical-topographic-maps-preserving-past

View/download maps on the TopoView site:
https://ngmdb.usgs.gov/topoview/

Section of single track Canyon Trail built in 1990:
https://www.trailcenter.org/newsletter/2000/winter2000/winter2000-19f.htm

Future plan: I want to try to hike along the top of the ridge between the Canyon Trail and Stevens Creek between the Table Mtn. and Grizzly Flat trails. I'm hoping there might be some exposed sedimentary rock outcrops up there that might show if this block has been tilted in the past.

More to come...
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