According to Dan Muhs et. al. in the Quaternary Science Reviews 105 (2014)
pages 209-238:
The late Quaternary uplift rates for the northern Channel Islands are about
0.15 m/1,000 years.
By contract, the Western Transverse Range is uplif rate is about 1.5 m/1,000
years or ten times faster.
I met Dan Muhs once on an IPCO boat to the islands, and he explained how the
action of the “Big Bend” in the San Andreas Fault aided by the Garlock Fault
creates this unusual action of the tectonic plates.
Fascinating stuff! The article may still be in the One Drive under CHIS
Uplift rates Muhs 2014.
- Tara Brown
On Aug 2, 2020, at 10:03 AM, thusone (Redacted sender "thusone" for DMARC)
<dmarc-noreply@xxxxxxxxxxxxx> wrote:
Amazing advances in science! This story doesn’t do the math or mention
rising water levels; only sinking land levels, and not uniformly everywhere.
Shirley Johnson
ThusOne@xxxxxxx <mailto:ThusOne@xxxxxxx>
The study revealed sinking coastal hotspots in San Diego, Los Angeles, Santa
Cruz, and San Francisco. These cities have a combined population of 4 to 8
million people, who will be increasingly exposed to rapid land subsidence and
a greater risk of flooding in the coming decades.
“We have ushered in a new era of coastal mapping at greater than 1,000 fold
higher detail and resolution than ever before,” said study co-author
Manoochehr Shirzaei. “The unprecedented detail and submillimeter accuracy
resolved in our vertical land motion dataset can transform the understanding
of natural and anthropogenic changes in relative sea-level and associated
hazards.
...
Natural processes can cause land subsidence such as tectonics, sediment
loading, and soil compaction. Subsidence can also be caused by human
activities including groundwater extraction and oil and gas production
….
The current study measured the entire 1,350-kilometer long coast of
California from 2007 to 2018, compiling thousands of satellite images over
time to make a vertical land motion map with unprecedented resolution
The four metro areas that are most affected by land subsidence are San
Francisco, Monterey Bay, Los Angeles, and San Diego.
“The vast majority of the San Francisco Bay perimeter is undergoing
subsidence with rates reaching 5.9 mm/year,” said study lead author Em
Blackwell. “Notably, the San Francisco International Airport is subsiding
with rates faster than 2.0 mm/year.”
“The Monterey Bay Area, including the city of Santa Cruz, is rapidly sinking
without any zones of uplift. Rates of subsidence for this area reach 8.7
mm/year. The Los Angeles area shows subsidence along small coastal zones, but
most of the subsidence is occurring inland.”
The study is published in the journal Science Advances
<https://advances.sciencemag.org/>.
https://www.earth.com/news/californias-coast-is-vanishing-due-to-land-subsidence/
<https://www.earth.com/news/californias-coast-is-vanishing-due-to-land-subsidence/>
