Throughout the state, there are more than 100 active faults that
have produced earthquakes resulting in widespread damage and
deaths. In Southern California alone, since 1933, there have been
23 significant quakes of magnitude 5.9 or greater. The San
Andreas Fault, the major fault line running through California,
is expected to be the source for a major earthquake. It was the
source for the earthquake that leveled San Francisco in 1906.
Water infrastructure is vulnerable to earthquakes:
* In the Sacramento-San Joaquin Delta, man-made levees
dating back to 1850 are identified as at risk when a major
earthquake hits.
* The U.S. Geological Survey (USGS) estimates a magnitude
7.8 temblor on the southern portion of the San Andreas Fault will
cause major damage to infrastructure, including water lines and
dams.
A panel of experts in Southern California also has identified the
following risks as a result of a major earthquake:
* Likely major damage to the main aqueducts bringing water
to Southern California from Northern California and the Colorado
River. Repairs may be hampered due to damaged roads and
large-scale fires.
* In the following days after a major quake, there may be
no water available due to infrastructure breaks and loss of
power. After that, repairs will bring supplies online slowly.
Water districts and agencies have prepared earthquake
preparedness and emergency plans to address the emergency.
Also, groundwater basins will be used as emergency reservoirs to
make up the water shortages when imported supplies are
unavailable.
Nearly every resident of California has experienced an
earthquake. Even the youngest schoolchildren have the safety
procedure drilled into them: duck under a table, hold on, and
pray that it’s only a small one. Barring a truly catastrophic
quake, the situation usually ends there. You go on with your
day as if nothing had happened, the near catastrophe completely
forgotten. Most people assume that the danger ends after the
last remnants of the tremor share the ground. But there is a
much more sinister side effect of earthquakes that affects
daily life around California and much of the rest of the world:
contaminating the groundwater supply.
Sterling Construction Company, Inc. today announced that its
subsidiary, Road and Highway Builders, LLC, has been awarded a
$135 million heavy civil contract by the City of Los Angeles
for the construction of the North Haiwee Dam No. 2 in Inyo
County, CA. …The project will also involve the rerouting of
the Los Angeles Aqueduct, which supplies clean drinking water
to the city of Los Angeles, to allow for the appropriate
tie-ins for the dam construction.
Democratic lawmakers and advocates are urging Joe Biden to back
legislation proposing unprecedented investment in America’s
ailing water infrastructure amid the country’s worst crisis in
decades that has left millions of people without access to
clean, safe, affordable water. Boil advisories, leaky lead
pipes, poisonous forever chemicals, bill arrears and raw sewage
are among the urgent issues facing ordinary Americans and
municipal utilities after decades of federal government
neglect, which has brought the country’s ageing water systems
hurtling towards disaster. … Water supplies and
sanitation have been disrupted over and over in recent decades
– in Louisiana, Puerto Rico, California, Ohio and elsewhere …
Consider California’s water systems. That they are not designed
for what is coming seismically is no secret. Southern
California still imports most of its water, and all of that
imported water has to cross the San Andreas fault to get to us.
None of those crossings has been engineered to work after the
San Andreas breaks, and the Los Angeles Department of Water and
Power has estimated that it will take 18 months to repair all
of them. -Written by seismologist Lucy Jones, the founder of
the Dr. Lucy Jones Center for Science and Society and the
author of “The Big Ones.”
Although the 1971 San Fernando earthquake and the near failure
of the Lower Van Norman Dam have given rise to construction
improvements … the overwhelming majority of California dams
are decades past their design life span. And while earthquakes
still loom as the greatest threat to California’s massive
collection of dams, experts warn that these aging structures
will be challenged further by a new and emerging hazard:
“whiplashing shifts” in extreme weather due to climate change.
Tens of thousands of large dams across the globe are reaching
the end of their expected lifespans, leading to a dramatic rise
in failures and collapses, a new UN study finds. These
deteriorating structures pose a serious threat to hundreds of
millions of people living downstream…. In 2017, a
spillway collapsed at the 50-year-old Oroville Dam in
California’s Sierra Nevada foothills. It caused the evacuation
of around 180,000 people. The 770-foot dam is the highest in
the U.S. and, after repairs to the spillway, remains critical
to the state’s water supply.
Rancho California Water District’s Vail Dam Seismic and
Hydrologic Remediation Project was selected to apply for
funding as part of approximately $5.1 billion in Water
Infrastructure Finance and Innovation Act (WIFIA) loans
provided by the U.S. Environmental Protection Agency (EPA).
WIFIA loans provide financing assistance to help pay for water
infrastructure projects in the United States.
Has California overshot the runway? … There was a time
when our dams and aqueducts that allowed us to change the
course plotted by nature by not letting water be restricted to
water basins by physical barriers were considered a candidate
for of their wonders of the world. When it came to freeways, we
were the envy of the land. That was then and this is now. The
list of aging infrastructure that needs addressing is
staggering.
The Federal Emergency Management Agency has calculated the risk
for every county in America for 18 types of natural disasters,
such as earthquakes, hurricanes, tornadoes, floods, volcanoes
and even tsunamis. And of the more than 3,000 counties, Los
Angeles County has the highest ranking in the National Risk
Index.
Local utilities are looking for new ways to make Southern
California earthquake safe, and one way is by replacing aging
water pipes. The new pipes could help keep the water flowing
after a big one hits. LADWP is replacing critical areas along
its 7,000 miles of water pipes in Los Angeles with earthquake
resilient pipes to ensure water is still flowing after the
shaking stops.
The COO and assistant general manager of the Metropolitan Water
District of Southern California, where Pasadena sources a
significant amount of its water, will be discussing ways to
strengthen the water system against “catastrophic scenarios”
ranging from earthquakes and floods to climate change
and shifting regulations.
The Department of Water Resources recently published a summary
report of a comprehensive needs assessment of safety at
Oroville Dam. It comes after the reconstruction of the
spillways that were damaged and failed in 2017.
A 19-month study of the safety of the Oroville Dam project has
found no “unacceptable risks.” The Department of Water
Resources released its Comprehensive Needs Assessment on Oct.
30, and notes its findings generally agree with those of an
Independent Review Board and a regular five-year review by the
Federal Energy Regulatory Commission…
A team of experts released their findings Monday, concluding
that no urgent repairs are needed right now on the Oroville
Dam. The report goes on to say that the largest earthen dam in
America is safe to operate. However, the Oroville Dam is not
completely in the clear.
Assessments and evaluations of the Castaic Dam spillway in Los
Angeles County began Wednesday as part of a statewide effort to
reduce risks from major earthquakes or extreme weather events
to State Water Project infrastructure.
Last year, the U.S. Army Corps of Engineers, which maintains a
database of all the nation’s dams and their risk levels, raised
the risk classification for the Mojave Dam in San Bernardino
County, California, to high. The 200-foot-high earthen dam was
built in 1971 and, if it fails, threatens communities as far
away as 140 miles.
Hundreds of years ago, a giant lake — Lake Cahuilla — in
southern California and northern Mexico covered swathes of the
Mexicali, Imperial, and Coachella Valleys, through which the
southern San Andreas Fault cuts. … If the lake over the San
Andreas has dried up and the weight of its water was removed,
could that help explain why the San Andreas fault is in an
earthquake drought?
It all started with a 2002 state law demanding quake-resilient
water delivery. Nearly $5 billion later, San Francisco has
retrofit the system from Hetch Hetchy to the city, just now
crossing the finish line on the shore of Lake Merced.
Reclamation has identified a significant seismic risk problem
at Shasta Dam that may preclude the enlargement of Shasta Dam
in a safe manner. … In addition … modeling disclosed by
Reclamation to NRDC (see last page of this link) indicates that
enlarging Shasta Dam would reduce the water supply for State
Water Project contractors by an average of 14,000 acre feet per
year.
Valley Water this week began draining Anderson Reservoir in
preparation for a seismic retrofit of the body’s dam in east
Morgan Hill, but Gov. Gavin Newsom also vetoed a state Assembly
bill that would have expedited the project that the water
district has been planning for more than 10 years.
Santa Clara County’s largest reservoir will soon be nearly
empty, and will stay that way for the next 10 years. Under
orders from federal dam regulators, the Santa Clara Valley
Water District will begin a project to drain Anderson Reservoir
on Thursday, the first step in a $576 million effort to tear
down and rebuild its aging dam.
Anderson Reservoir will be closed to boating, fishing and all
recreational activities for the next several years starting
Oct. 1. That’s when the local water district will begin
draining the lake in order to begin construction on a new
discharge tunnel and seismically retrofitted dam.
Between February and July 2020, the East Bay Municipal
Utility District completed work on more than 20 community
infrastructure projects totaling $49 million. The projects
include rehabilitated neighborhood water storage tanks, miles
of new water distribution pipelines designed to withstand
earthquakes, and a new photovoltaic system to generate energy
from the sun.
Though they are not native to the Anderson Reservoir, the
steelhead population is in decline, making the local watershed
particularly important to preservation efforts.
A fish rescue has taken place in the South Bay, where the
Anderson Dam retrofit project is about to get underway. Using
nets and buckets, a team with the Valley Water District scooped
up Central California Coast steelhead in upper Coyote Creek to
save the fish and help the species survive.
The consolidation of multiple agencies into SCV Water makes
local coordination in emergencies much easier than in the past.
Partnerships with other agencies to the north and south of us
mean there are backup plans for dry years and places to store
excess water in wet years.
Valley Water biologists will be rescuing federally threatened
Central California Coast Steelhead and other sensitive fish
from Coyote Creek next week and relocating them to a more
suitable environment in the Coyote watershed.
On Tuesday, the Bureau of Reclamation submitted the B.F. Sisk
Dam Safety of Dams Modification Report to Congress. This is
Reclamation’s largest project under the 1978 Safety of Dams
Act, and when complete, will modernize the structure to reduce
risk to water supply and downstream communities in an
earthquake.
The Anderson Reservoir in Morgan Hill held back by a 240-foot
dam built in 1950 could be rebuilt following the State
Assembly’s passage of AB 3005 in June. … The project would
cost about $576 million but still needs to pass through the
State Senate.
Reps. Grace F. Napolitano (D-CA-32) and Linda T. Sánchez
(D-CA-38) announced that the FY2021 Energy and Water
Appropriations bill is providing $384,900,000 as part of the
U.S. Army Corps of Engineers’ Dam Safety and Seepage Program.
Valley Water has many critical projects in various stages of
development, including flood protection projects,
infrastructure improvements and work to protect our
environment. But our top priority remains an effort to retrofit
and strengthen Anderson Dam, home to Santa Clara County’s
largest reservoir, so it can safely withstand a strong
earthquake.
The City Council heard a report on the possibility of
rehabilitating the Lake Wohlford Dam, which was first
constructed in 1895 as part of Escondido’s local water system,
to address seismic deficiencies rather than replacing the dam
altogether.
In an effort to move forward a $576 million Anderson Dam
Seismic Retrofit Project, the California State Assembly passed
AB 3005 on June 8, the Expedited Dam Safety for Silicon Valley
Act, facilitating the construction of the project. Assemblyman
Robert Rivas (D-Hollister, Calif.), who wrote the bill, says
the overwhelming vote of bipartisan support shows the
importance in fixing the dam.
Two agencies are studying the feasibility of supplementing a
seismic safety project planned for B.F. Sisk Dam with a second
component that would increase the capacity of San Luis
Reservoir. … While the dam safety project involves raising
the crest of the earthen structure as much as 12 feet, as well
as seismic reinforcements, it does not, in itself, increase
capacity in the reservoir.
Three months after federal dam safety regulators ordered
Anderson Reservoir, the largest reservoir in Santa Clara
County, to be drained due to earthquake concerns, new details
are emerging on what will happen to all that water, the fish
that depend on it, and the water supply for Silicon Valley.
In recognition of National Dam Safety Awareness Day, Andy
Mangney who serves as the Field Engineering Branch Chief
overseeing DSOD’s dam inspection and monitoring program, took
some time to answer questions about what DSOD is doing to
protect Californians.
In May, Cyclone Amphan made landfall in Bangladesh and eastern
India. The category 5 storm forced around 3 million people to
flee their homes. With this scenario in mind, a group of
disaster experts published guidelines for political leaders and
emergency managers so that they can prepare before the storms
hit.
The 2008 financial market crash was called a “black swan” event
— an extreme catastrophic event that was not anticipated. We
hope that when a catastrophic dam failure occurs in the United
States it will not be called a black swan, since there is
already strong evidence that the combination of aging and
poorly maintained infrastructure and climate extremes could be
very deadly.
As part of an effort to modernize Pyramid Dam located in Los
Angeles County, the Department of Water Resources (DWR)
recently completed assessments for the dam’s gated and
emergency spillways. The Pyramid Dam Modernization Program is
now entering the investigations phase, which includes
structural and hydraulic analyses for the gated spillway and
erodibility analysis for the emergency spillway.
Bureau of Reclamation employees from its Technical Service
Center were able to use visual and digital technology as they
worked remotely to complete and transmit the 60% design
specifications and drawings for the B. F. Sisk dam safety
modification. This modification, estimated to cost $1.1
billion, is the largest in the history of Reclamation’s Dam
Safety Program.
The US Bureau of Reclamation is to resume a seismic safety
modification project at Boca Dam near Truckee in California
today, following its seasonal closure in November 2019, with
social distancing guidelines recommended by the Centers for
Disease Control and Prevention and other COVID-19 precautions
to be followed during construction.
No one knows exactly how this coming fire season will shake
out, but experts and fire officials agree the COVID-19 pandemic
will make an already hard job much tougher.
California has evacuation plans for earthquakes, floods,
mudslides and, of course, wildfires, but what if one of those
disasters occurs as the state is dealing with the coronavirus
outbreak when everyone is being urged to stay home? State and
local officials are trying to figure that out.
The Bureau of Reclamation and the California Department of
Water Resources are conducting exploratory work, including
clearing, excavation and controlled blasting of rock material
in the Basalt Hill area near B.F. Sisk Dam, located between Los
Banos and Gilroy, between 6 a.m. to 8 p.m. during April and
May. The exploratory findings on Reclamation lands will help
identify size and quality of granular material for the planned
Safety of Dams Modification project.
The Retrofit Project would mitigate earthquake hazards
currently threatening the Redwood Valley County Water
District… The county said the project would replace
approximately 10,577 feet of main water lines, include
installation of around 3,300 feet of new water main lines, and
replace 146 water services lateral connections. The project
will cost an estimated $6,200,000, including construction
support and contingency.
U.S. Rep. Grace Napolitano has convinced the U.S. Army Corps of
Engineers to spend $393.2 million to fix the Whittier Narrows
Dam, but she still has to persuade Congress to appropriate the
money. With other congressional members at her side on Friday,
Napolitano, D-El Monte, began her effort with a tour of the dam
near Lincoln Avenue in Montebello.
Valley Water in Santa Clara, Calif., doesn’t fully agree with a
Feb. 20 directive from the Federal Energy Regulatory Commission
(FERC) to drain its Anderson Dam as the water district waits to
begin upgrades to the structure near the Calaveras Fault.
A federal order to drain Silicon Valley’s largest drinking
water reservoir has thrown the region into disarray, with
multiple agencies pointing fingers at each other and some local
leaders fearful their cities could run out of water, not this
summer but the following one.
Silicon Valley water officials assured the public Tuesday they
have enough water to avoid shortages this summer, even after
federal regulators announced that Anderson Reservoir, the
region’s largest, must be completely drained beginning this
fall because of the risk its dam might collapse in a major
earthquake.
In a dramatic decision that could significantly impact Silicon
Valley’s water supply, federal dam regulators have ordered
Anderson Reservoir, the largest reservoir in Santa Clara
County, to be completely drained starting Oct. 1. The 240-foot
earthen dam, built in 1950 and located east of Highway 101
between Morgan Hill and San Jose, poses too great of a risk of
collapse during a major earthquake, the Federal Energy
Regulatory Commission, which regulates dams, has concluded.
The 3.5 magnitude earthquake that hit early Friday morning near
Interstate 5 was only a mile away from Castaic Dam. That’s
important, because the dam has one of the lowest safety ratings
in Los Angeles County — due to seismic vulnerabilities.
Plans to replace the Lake Wohlford dam are now on hold as
Escondido investigates other, less expensive options because
the projected cost of the project has escalated to more than
$50 million. It was nearly 13 years ago when state inspectors
determined that the top quarter of the dam might liquefy in the
event of a major earthquake…
An audit of 650 California dams considered hazardous found that
only a small fraction have completed emergency plans required
after the Oroville Dam spillway collapsed three years ago and
forced the evacuation of nearly 200,000 people.
The preferred alternative to address seismic safety concerns at
the structure, commonly known as San Luis Dam, involves raising
the crest of the dam by 12 feet, adding shear keys to prevent
slippage and construction of downstream berms to strengthen the
structure… Work on the project is expected to begin in August
2021
The vast majority of California’s major dams aren’t adequately
prepared for an emergency. Three years after the near-disaster
at Oroville Dam, only 22 state-regulated dams have finalized
emergency plans — out of 650 major dams that are required by
law to have plans in place — according to a report issued
Thursday by State Auditor Elaine Howle.
Climate change is already affecting water management across the
state. Small rural communities with ongoing drinking water
challenges are especially vulnerable to greater extremes
brought on by a warming climate. We talked to Jan Coppinger, a
special district administrator from Lake County, about how the
county’s small water systems have dealt with an especially
devastating string of natural disasters.
San Francisco Supervisors on Tuesday unanimously declared a
State of Urgency, calling on the city to expand its Emergency
Firefighting Water System to ensure the entire city is
protected in the event of a major earthquake or fire.
Currently, the water system only covers about one third of the
city, leaving neighborhoods in the city’s west and south sides
vulnerable.
California is on track to build a $1 billion dam and create a
giant reservoir at Pacheco Pass that will dwarf the existing
reservoir and dam near Highway 152 east of Gilroy, with
construction beginning in 2024. New evidence from an
independent nationwide study of dam safety suggests a new
incentive for the project—safety…
In response to concerns about power outages, wildfires and the
water used to put them out, local water officials unveiled
details of an emergency plan Tuesday, explaining how SCV Water
is prepared for emergencies.
The U.S. Army Corps of Engineers announced that it has changed
its risk characterization of the Mojave River Dam from low to
high urgency of action. The earthen dam was built in the 1970s
near the San Bernardino Mountains northeast of Los Angeles. It
was designed for flood control and is usually dry.
As part of a statewide effort to reduce seismic and hydrologic
risk to State Water Project facilities, the California
Department of Water Resources’ Castaic Dam Modernization
Program begins this week with an assessment of a stream release
structure at Castaic Dam in Los Angeles County.
Effects from the two July 2019 Ridgecrest, CA earthquakes were
observed in several USGS continuous groundwater-level
monitoring sites in California, Nevada, and Arizona.
Valley of the Moon is a small community of 27,000 people tucked
away not far from Sonoma. It’s quiet normally, but the general
manager of their water district has become quite the opposite.
“I will not be the guy who didn’t say he did everything he
could to get water to his people,” said Alan Gardner, general
manager of Valley of the Moon Water District.
The 2018-2019 Sonoma County Grand Jury report, issued in July,
addresses several areas of concern that county residents and
governments should be aware of, and prepare for. One of them is
found in the “water report,” a 17-page document that poses the
question, “Will there be water after an earthquake?”
Can artificial intelligence save the L.A. water supply from a
big earthquake? USC researchers have embarked on an innovative
project to prove that it can. Using federal funds, experts at
the USC Center for Artificial Intelligence in Society (CAIS)
are working with Los Angeles city officials to find solutions
for vulnerable plumbing. The goal is to make surgical
improvements to strategic pipelines to keep water flowing after
shaking stops.
Today, the California Department of Water Resources began
assessment work on Pyramid Dam’s spillways in Los Angeles
County as part of a statewide effort to reduce seismic and
hydrologic risk to State Water Project facilities spanning 705
miles throughout California.
It’s only 8 inches in diameter, and each segment ranges from 10
to 18 feet. But EBMUD’s quake-resistant pipes may well prove to
be a true lifeline, keeping the water flowing when the next big
quake hits along the Hayward fault.
Lake Temescal in Upper Rockridge sits atop the Hayward Fault,
which passes underneath the right abutment of the manmade
lake’s aged dam. Experts agree that creep has been observed
near Lake Temescal Dam, but disagree on whether this indicates
the area is at risk of suffering major damage during a strong
quake.
The twin earthquakes that rattled Southern California last
month caused up to $5.2 billion in damages to the China Lake
Navy base, according to estimates in a report released
Wednesday by the base. The report cites extensive damage among
the nearly 3,600 facilities at the base, including 1,341
buildings, as well was infrastructure like water supplies and
power.
Mediterranean climates, like California’s, typically follow
boom and bust cycles, marked by a predictable shift between
cold and wet and hot and dry. But the changing climate will
amplify that pattern with weather that is, at times, wetter and
at other times hotter.
The recent Ridgecrest earthquakes jolted less than 50 miles
away from Lake Isabella, where the Isabella Dam is in the midst
of a $600 million improvement project by the US Army Corps of
Engineers. How did the dam fare during the earthquakes, and how
much longer until the upgrades will be complete?
Nearly two dozen government officials met Wednesday to discuss
options for one of the state’s most important and imperiled
water sources. Scoggins Dam was built in the early 1970s to
hold back water from the Tualatin River to form Hagg Lake. In
recent years, it has been classified as a seismically at-risk
dam that needs to be modified in order to reduce downstream
hazards in the event of a large earthquake.
The magnitude 7.1 quake that split open the floor of the Mojave
Desert on July 5 shook up life far beyond its epicenter. In
Death Valley National Park — some 70 miles away from where the
earthquake was centered — 10-foot waves erupted inside Devils
Hole, a 10-foot-wide and 25-foot-long pool that is the sole
home to the endangered Devils Hole pupfish.
An earthquake doesn’t have to happen in your neighborhood or
city, or even your region, for it to have an impact, especially
on Southern California’s water supply. According to UCLA
Professor Jon Stewart, the three main water systems that bring
water to Southern California each cross the San Andreas Fault
at least once.
The East Bay Municipal Utility District now has a back-up plan
that includes filling water tanks to capacity during Red Flag
Warnings… Portable generators would go in cities like
Berkeley, Castro Valley, and San Ramon starting on Aug. 1.
Other Bay Area water agencies also have plans in place.
Residents of a small Southern California desert community hit
hard by this month’s big earthquakes no longer need to boil tap
water. San Bernardino County authorities announced Wednesday
the boil-water notice for Trona and neighboring areas has been
lifted and citizens do not need to rely on bottled water.
If PG&E shuts down power as part of its plan to prevent
fires in northern California, the water will keep flowing in
the Valley, thanks to Zone 7 Water Agency’s preparations. …
Zone 7 has two plants for water treatment and distribution …
Both have backup generators in case power stops. Each has
a three-day supply of fuel, but the agency also has contracts
with other generator suppliers who can each roll out at least
three days of juice.
The updated guide contains dozens of best practices, grouped
into 15 main categories, that water and wastewater systems can
implement to reduce security risks to their IT and OT systems.
Each recommendation is accompanied by links to corresponding
technical resources.
New research shows that the extreme weather and fires of recent
years, similar to the flooding that has struck Louisiana and
the Midwest, may be making Americans sick in ways researchers
are only beginning to understand.
The Grand Jury’s main critique was that the water district’s
prediction that water service could be restored within three
days is too optimistic. The report suggests that two weeks to
six months without reliable water service is a more realistic
estimate in the aftermath of a major earthquake.
The East Bay Municipal Utility District is replacing an aged
and faulty 3,000-foot water pipeline that would most likely
rupture during a major earthquake and cut off water service to
residents for weeks, if not months. The current pipeline has
averaged a major break each year for the last 30 years,
with increasing regularity, as this land has continued to shake
and shift.
The U.S. Geological Survey said the chance of a quake larger
than Friday’s 7.1 temblor is less than 1% and the chance of a
magnitude 6 or higher is down to 6%. … Trona, which has about
1,800 residents, lost power until Monday and remained without
water on Wednesday.
The quakes left a majority of the town without water or natural
gas service over the weekend. Pacific Gas & Electric restored
gas service Monday afternoon, but water services remains out.
San Diego faces a hidden earthquake threat — to its water
supply. A quake, even one so far away that nobody in San Diego
feels it, could force mandatory water-use restrictions. That’s
because most of San Diego’s water comes from hundreds of miles
away through threads of metal and concrete that connect us to
distant rivers and reservoirs.
Officials in two damaged desert communities worked Sunday to
repair roads and restore utilities following the largest
earthquake in Southern California in nearly two decades. …
Friday’s quake sparked several house fires, shut off power,
snapped gas lines, cracked buildings and flooded some homes
when water lines broke.
Since the turn of the 20th century, the Colorado River and its
tributaries have been dammed and diverted to sustain the growth
of massive cities and large-scale farming in the American
Southwest. Attempts to bend the river system to humanity’s will
have also led to all kinds of unintended consequences. In
Colorado’s Paradox Valley, those unintended consequences take
the form of earthquakes.
After a disaster, Sonoma Water will try to restore service as
quickly as possible. The agency already has installed isolation
valves so that it can cut off water around breaks and has some
emergency water reserves in place. It estimates that water
service could be restored in as few as three days after a
moderate earthquake. The grand jury concluded that was an
overly rosy prediction.
Del Puerto Water District and Central California Irrigation
District have developed the reservoir project without many
public concerns rising to the surface. That was until Patterson
city staff members showed up for Wednesday’s meeting. Maria
Encinas, a city management analyst, asked about a risk
assessment for adjacent communities like Patterson. A failure
in the dam on Del Puerto Creek, on the west side of Interstate
5, would appear to flood part of the city of 23,700, including
perhaps the downtown area in Patterson.
Federal engineers are raising alarms that a “significant flood
event” could breach the spillway of Southern California’s aging
Prado Dam and potentially inundate dozens of Orange County
communities from Disneyland to Newport Beach. After conducting
an assessment of the 78-year-old structure earlier this month,
the U.S. Army Corps of Engineers announced that it was raising
the dam’s risk category from “moderate” to “high urgency.”
By monitoring tiny changes to the Earth’s gravitational field,
the GRACE satellites have been pinpointing the distribution of
fresh water on our planet for almost two decades. But as Marric
Stephens explains, a new follow-on mission is also helping with
plans for a space-based gravitational-wave detector
The construction doubled the previous width of the dam from the
top to the bottom of the buttress, which was previously
susceptible to seismic activity. New valves and pipelines were
also included to control the lake level and allow for quicker
drainage in the event of an emergency.
In 2017, a swarm of seismic activity occurred near California’s
Long Valley Caldera in the Mammoth Mountain area. During the
same period of seismic activity, the area had high levels of
flooding due to snowmelt. The 2016-2017 winter brought heavy
snow that created one of the largest snowpacks ever recorded in
California’s history. A record amount of snowfall occurred in
the same region this year, raising the question of whether the
same occurrence will happen in 2019.
A spring surge of meltwater, seeping through vertically tilted
layers of rock, caused a seismic swarm near California’s Long
Valley Caldera in 2017, according to research presented at the
2019 SSA Annual Meeting. The unusual event prompted U.S.
Geological Survey researcher Emily Montgomery-Brown and her
colleagues to look back through 33 years of seismic and water
records for the region. They found that rates of shallow
seismicity were about 37 times higher during very wet periods
versus dry periods.
Work to protect Lake Gregory from a disastrous earthquake is
done. And, just in time for summer. Crews recently finished
retrofitting the 80-year-old seismically unsound dam that
protects the lake, at the heart of Crestline, bringing an end
to years of traffic, noise and other impacts — current and
potential — on the unincorporated mountain community.
Dozens of computer coding teams from around San Joaquin County
were tasked to create an app in roughly seven hours. The issue:
following the destruction caused by the malfunction of the
Oroville Dam in February 2017 and the evacuation of more than
180,000 people, could there be an app that can track dam
leakage, seismic activity and other structural impacts and
communicate with the appropriate individuals to help deter
another disaster?
Oregon’s dam safety regulations are getting an overhaul, for
the first time in nearly a century. A bill pending in the
Legislature would rewrite the laws governing construction,
inspections and enforcement authority for hundreds of
state-regulated dams. The bill would increase the state’s power
to force owners of aging, dangerous dams to do maintenance and
make repairs. And it would require state approval and oversight
of all new dam construction and removal of old dams.
Just months before the Woolsey Fire, Las Virgenes Mutual Water
District had joined CalWARN, a mutual assistance system set up
for water utilities. General manager Dave Pedersen had heard
about it from a neighboring agency. Before dawn Nov. 9, the
district requested emergency generators. Within a few hours,
they had gotten a response.
Southern California gets much of its water supply from Northern
California – so what will happen if the “Big One” – a major
earthquake – cuts that supply off? KVCR’s Benjamin Purper
finds out in this report.
Scientific monitoring in the Pacific Ocean, using buoys to take
seawater temperatures, screeched to a halt when the government
recently shut down for 35 days. But those efforts to monitor El
Nino, the warming of the equatorial Pacific Ocean that affects
global weather patterns, are just some of the shutdown’s
impacts on science that Kevin Trenberth describes.
A coalition of environmental groups has called on California
members of Congress to prioritize the San Luis (B.F. Sisk)
Dam seismic remediation over federal funding for new California
dams. San Luis Dam is in a very seismically active area.
Independently reviewed risk assessments for Reclamation have
shown that a large earthquake could lead to crest settlement
and overtopping of the dam, which would result in large
uncontrolled releases and likely dam failure.
The earthquakes hit just days after last year’s
near-catastrophe at Oroville Dam, when the spillway cracked
amid heavy rains and 188,000 people fled in fear of flooding.
The timing of the two small tremors about 75 miles north of
Sacramento was curious, and frightening.
At 8:29 a.m. on Nov. 30, part of the rock slab underneath the
Pacific Ocean 7 miles north of Anchorage, Alaska, shifted,
causing a magnitude 7 earthquake. As Anchorage was preparing
for the day, the quake ripped apart roads, shattered windows
and ruptured water and gas lines in and around the city.
A leading earthquake expert says San Diego should consider
accelerating replacement of aging water pipes and completing a
comprehensive inventory of local buildings, especially
structures made of unreinforced brick. … She [Dr. Lucy
Jones] said the water system is typically a city’s most
vulnerable point in an earthquake because shifting ground
cracks pipes, potentially depriving a recovering community of
its crucial water supply.
A ballot measure that would give San Francisco the money to
start rebuilding the Embarcadero seawall was approved by voters
Tuesday by a comfortable margin. Proposition A, which needed a
two-thirds vote to pass, had nearly 82 percent support, with
206,446 ballots tabulated.
The San Andreas fault begins its dangerous dance through
California at the Salton Sea, at a spot that seismologists long
have feared could be the epicenter of a massive earthquake. …
A muddy spring mysteriously has begun to move at a faster pace
through dry earth — first 60 feet over a few months, and then
60 feet in a single day, according to Imperial County
officials.
In recent decades, San Franciscans have embraced the reborn
Embarcadero waterfront as kind of front yard, and at noon on a
weekday it crowds with tourists, skateboarders, entrepreneurs
and other locals. But underneath wheels and feet, three and a
half miles of seawall is cracking and crumbling, vulnerable to
rising waters or a major earthquake.
Tom Heaton thought it was crazy when, back in the 1970s, he
first heard about the concept of an earthquake early warning
system. Japan’s high-speed rail system already was using the
technology to slow down trains before shaking from a distant
earthquake hit. But the more the young Caltech scientist did
his calculations, the more he dreamed of bringing the system to
California.
Automated alerts from the fledgling West Coast earthquake early
warning system are ready to be used broadly by businesses,
utilities, schools and other entities but not for mass public
notification, officials said Wednesday.
More than a dozen years have passed since the U.S Army Corps of
Engineers became concerned about water seeping through the
auxiliary dam at Isabella Lake — not to mention the possibility
of a massive earthquake leveling the earthen structure.
“We will be able to reproduce earthquake motions with the most
accuracy of any shake table in the world,” said Joel Conte, the
UC San Diego structural engineer who is overseeing the project.
“This will accelerate the discovery of the knowledge engineers
need to build new bridges, power plants, dams, levees,
telecommunication towers, wind turbines, retaining walls,
tunnels, and to retrofit older structures. …”
As an earthquake warning system becomes a reality for more
Californians, a big question arises: What can you do if you
know shaking is coming to you? … 8. Beneath a dam Get to
high ground.
Along the California coast and across the world, dozens of
deep-sea ocean sensors are a first line of defense that warns
officials when a devastating tsunami is coming. When an
earthquake strikes, the sensors capture the movement of the
ocean waters, giving authorities precious time to alert
residents to move to higher ground.
After toiling away in the remote hills east of Interstate 680
on the Alameda-Santa Clara county line for seven years,
hundreds of construction workers have finally finished the
largest dam built in the Bay Area in 20 years. The 220-foot
tall dam at Calaveras Reservoir — as high as the roadway on the
Golden Gate Bridge soars above San Francisco Bay — replaces a
dam of the same size, built in 1925.
San Francisco water officials were inspecting for earthquake
damage Monday at a dam under construction in the South Bay
after a small temblor shook the area the night before.
California’s nascent earthquake early-warning system had
another successful run Tuesday night when a 4.4 magnitude
temblor hit the La Verne area. The quake was too small to cause
much damage but was felt over a wide area.
Horror tales from recent earthquakes overseas are moving people
in Seattle, Portland and along the Pacific Northwest coast to
give a crap about where to crap after a major earthquake. It’s
not something we typically discuss in polite company, but
disaster planners say that when water and sewage service fails,
finding a place to poop is a big deal.
Research suggests the magnitude 6.0 earthquake that rocked
California wine country in 2014 may have been caused by an
expansion of Earth’s crust because of seasonally receding
groundwater under the Napa and Sonoma valleys.
On the ground once marked by devastation, a new city is rising.
The 1989 Loma Prieta earthquake battered the gritty South of
Market district, damaging the Embarcadero Freeway that walled
off downtown San Francisco from the bay and left city leaders
with a choice: Do they repair and retrofit it, or envision
something bolder?
Scientists have long held out hope that major earthquakes might
be predictable from their “foreshocks” — the smaller tremors
that often occur right before a major quake. But a new study
suggests that the foreshock theory is, well, shaky.
When a catastrophic earthquake hits California, buildings will
topple and potentially hundreds could be killed. But what gets
less attention is the wrenching aftermath of such a huge
temblor, which could leave whole neighborhoods torched by fires
uninhabitable and hundreds of thousands of people without a
home.
Lassen Peak had been rumbling for days. Glowing hot rocks
bounded down the slopes. Lava was welling up into a freshly
created crater. Then, on this day 103 years ago, it exploded in
a way California would never forget.
The town of Mammoth Lakes, in California’s eastern Sierra
Nevada, is generally known for two things: epic skiing in
winter, thanks to the very high elevation of its ski mountain;
and volcanic activity, because the mountain is a simmering
volcano. It’s normal to hike or ski around Mammoth and smell
the sulfurous gases venting from gurgling magma deep under the
mountain. That magma is also a rich source of geothermal power.
A swarm of small earthquakes hit a town near the U.S.-Mexico
border Saturday and continued into Sunday. Dozens of quakes
were reported in and around Ocotillo Wells in Imperial County,
six of them larger than a magnitude 3, according to the U.S.
Geological Survey.
A magnitude 4.2 earthquake struck about 3 miles northwest of
the Geysers geothermal field Wednesday evening and was followed
by a series of aftershocks, the U.S. Geological Survey said.
… The Geysers region, about 90 miles north of San
Francisco, is one of the most seismically active regions in the
United States.
Seismologist Lucy Jones said on Twitter that the temblor
occurred in a “complex part” of the San Andreas fault under the
San Bernardino Mountains and was not far from the epicenter of
a 1986 quake that measured 5.9 magnitude.
The water is rising. Closures are lifting. And enthusiasm is
building. After more than a decade of planning, construction
and disappointing water levels, Lake Perris is on its way to
being the recreational paradise it was before fears that its
dam would collapse in an earthquake significantly curtailed
activities.
Why was an earthquake in Virginia felt at more than twice the
distance than a similar-sized earthquake in California? The
answer is one that many people may not realize. Earthquakes
east of the Rocky Mountains can cause noticeable ground shaking
at much farther distances than comparably-sized earthquakes in
the West.
The U.S. Geological Survey over the last year has recorded
dozens of weak and shallow earthquakes near Oroville Dam and
its spillways. And nearly all the tremors — including a
magnitude-0.8 quake recorded Wednesday — share the same
designation: “Chemical explosion.”
Property values are soaring to stratospheric levels. The tech
economy is booming, fueling fast-paced development and spending
on home renovations that ranks among the nation’s highest. But
at a time of unparalleled prosperity in the Bay Area, there is
growing concern that the region is not using more of its
largesse to prepare for its greatest natural threat: a major
earthquake.
Eight hundred deaths, 18,000 people injured, more than $82
billion in property damage and business losses, and 400 fires
that would claim more lives and permanently alter the urban
landscape of the San Francisco Bay region.
As is often said, it’s not a matter of if, but of when, a large
earthquake strikes the heart of one of California’s most
densely populated regions. State officials and local agencies
know the clock is ticking, and mile by mile, pipe by pipe, work
crews are replacing or retrofitting water lines throughout much
of the Los Angeles and San Francisco Bay areas. Upgrades have
also been made in the Sacramento-San Joaquin Delta …
A landmark report by the U.S. Geological Survey estimates that
at least 800 people could be killed and 18,000 more injured in
a hypothetical magnitude 7 earthquake on the Hayward fault
centered below Oakland. … More than 400,000 people could
be displaced from their homes, and some East Bay residents may
lose access to clean running water for as long as six months.
Sailors arriving in San Francisco in the 19th century used two
giant redwood trees perched on a hill to help guide their ships
into the bay. The redwoods were felled for their lumber at
around the time of the gold rush, but San Francisco now has a
new beacon: Salesforce Tower, the tallest office building in
the West.
Earthquake activity in California’s Channel Islands shouldn’t
be all that surprising. After all, earthquakes created the
Channel Islands. In fact, mountains throughout California are
generally creations of earthquakes, seismologist Lucy Jones
said.
The 5.3 magnitude off the coast of Southern California didn’t
do damage on the mainland, but it appears have caused some
earth movement on Santa Cruz Island.
The Bay Area’s deeply unequal cities, home to mansions and
shacks alike, are linked by one thing: thirst. Banding
together, the region’s water agencies on Tuesday unveiled the
latest upgrades to a vast network that connects six million
people and provides mutual aid in a crisis, such as an
earthquake or severe drought.
A number of cities big and small in Southern California are
taking steps to identify seismically vulnerable buildings for
the first time in a generation, acting in part on the
devastating images of earthquake damage in Mexico and elsewhere
around the world.
California’s seismic construction requirements are designed to
protect the lives of those inside. But even with the most
modern codes, building to the state’s minimum requirements
would leave even new buildings severely damaged in a major
earthquake — to the point of being a complete loss.
The Marin Municipal Water District will spend $400,000 to
protect a key treatment plant in case of a big earthquake. The
district’s San Geronimo Water Treatment Plant in Woodacre
provides half of the water supply to the county, but two
circular clarifiers were built prior to current seismic
standards and stand vulnerable to a large temblor.
Mexico City got a substantial warning before the shaking from a
distant earthquake arrived Friday — some 30 to 60 seconds
broadcast over loudspeakers from an earthquake early warning
system. It was another success for Mexico City’s earthquake
warning system — one which California, Oregon and Washington
state still lack, and one that is an ongoing target for
elimination by President Trump.
Nearly three-quarters of San Francisco voters would support a
bond measure of up to $500 million to improve the city’s
disintegrating seawall, a piece of infrastructure that is
largely unseen but that experts say is of vital importance in
protecting the city against major earthquakes as well as sea
level rise.
If an earthquake similar to the one in 1906 shook the San
Francisco Bay Area, nearly 69,000 houses would likely be
uninhabitable and more than 200,000 people could be displaced,
according to a new report.
In a fast-growing Inland Empire churning out new housing
tracts, the city of Redlands is a throwback to an older, more
regal era. The college town is graced by historic mansions, old
orange groves and a vintage downtown that stands in deep
contrast to the region’s big-box shopping centers and
drive-thru eateries.
There’s been a shakeup in Riverside’s earthquake preparation
plans. Riverside Public Utilities signed a 90-day,
$45,000, contract with “earthquake lady” Lucy Jones in
November.
California earthquakes are a geologic inevitability. The state
straddles the North American and Pacific tectonic plates and is
crisscrossed by the San Andreas and other active fault systems.
The magnitude 7.9 earthquake that struck off Alaska’s Kodiak
Island on Jan. 23, 2018 was just the latest reminder of major
seismic activity along the Pacific Rim.
The strong earthquake off the coast of Alaska on Monday caused
1-foot waves in Devils Hole, a water-filled cave that’s home to
critically endangered pupfish in Death Valley National Park.
New data from state geologists show that an earthquake fault
runs below Rodeo Drive and Beverly Hills’ shopping district,
heightening the known seismic risk in an area famous for
Cartier, Gucci, Prada and other luxury brands. The California
Geological Survey’s final map has the Santa Monica fault zone
cutting through the so-called Golden Triangle, running between
Santa Monica and Wilshire boulevards.
A magnitude-7.9 earthquake in the Gulf of Alaska triggered
minimal tsunami activity Tuesday morning, but if the event
occurred 100 miles to the north, it might have unleashed a
monster tidal wave.
This month’s tragic mudslides in Montecito, California are a
reminder that natural hazards lurk on the doorsteps of many
U.S. homes, even in affluent communities. Similar events occur
every year around the world, often inflicting much higher
casualties yet rarely making front-page headlines.
South Reno has been shaking, ever so gently, for six days now.
If you live there — near Galena High School or where the Mount
Rose Highway goes below the I-580 — you likely haven’t felt
much, if anything. But earthquake detecting instruments in the
area have picked up more than 230 small temblors since late
last Thursday.
Scenic hill slopes can be inspiring – or deadly, as we are
seeing after the disastrous debris flows that have ravaged the
community of Montecito, California in the wake of heavy rains
on Tuesday, Jan. 9, 2018. … As mountains rise, erosion tears
them down. And Southern California’s mountains are rising fast,
squeezed up by the action of the region’s active faults.
Per EBMUD’s standard response protocols after an earthquake,
staff conducted inspections of the water treatment plants,
wastewater treatment plant, and other critical facilities.
t was a sharp jolt but also a warning of something much more
violent that could be coming. An estimated 9.8 million people
felt a magnitude 4.4 earthquake that rumbled across the Bay
Area early Thursday, the U.S. Geological Survey reported.
An earthquake centered in the Berkeley-Oakland area shook the
Bay Area at 2:39 a.m. Thursday, according to the U.S.
Geological Survey. The 4.4 shaker, near the Claremont Hotel in
the East Bay Hills, was along the Hayward Fault about 8 miles
deep, the USGS said.
A series of small earthquakes broke Wednesday and early
Thursday about eight miles northeast of Julian, causing shaking
that was felt across a wide area of the county, the U.S.
Geological Survey said
The San Jacinto fault may not be shaking yet, but it’s
trembling. And if it goes, according to one study, it could
rupture along with the San Andreas fault–producing a
catastrophic earthquake.
When the Big One hits California – and seismologists say
it’s not if, but when – there might not be blaring sirens or
vibrating phones giving people a precious few seconds to
prepare. … California’s earthquake warning system, long
discussed and partially built, remains incomplete and in limbo.
The 7.1 magnitude earthquake that shattered buildings and left
more than 200 dead in and around Mexico City is another
powerful reminder of what could happen when — not if — another
major temblor strikes the Bay Area.
Scientists say it’s possible for Southern California to be hit
by a magnitude 8.2 earthquake. Such a quake would be far more
destructive to the Los Angeles area because the San Andreas
fault runs very close to and underneath densely populated
areas. … The aqueducts that bring in 88% of Los Angeles’
water supply and cross the San Andreas fault all could be
damaged or destroyed, [Lucy] Jones said.
San Diego’s Rose Canyon fault is capable of producing a
magnitude 6.9 earthquake that could kill 2,000 people and
inflict $40 billion in property damage, according to a
preliminary study sponsored by the Earthquake Engineering
Research Institute. … The shaking would break scores of
water and sewer lines, possibly causing wastewater to spill
into San Diego and Mission Bays.
One day, next to the traffic map and weather forecast on your
smartphone, seismologist Thomas H. Jordan envisions an app that
you can check to see when the chances of a major earthquake in
California rise. Jordan, director of the Southern California
Earthquake Center, is quick to make clear this is not an
earthquake prediction.
For years, scientists have drawn up terrifying scenarios of
widespread destruction and chaos that would come to Southern
California when a catastrophic earthquake hits. … While epic
flooding is different from a powerful temblor, both natural
disasters fundamentally alter daily life for months or years.
A pair of earthquakes struck Northern California Tuesday
morning, including a magnitude 3.0 shaker off the coast of San
Francisco, according to the U.S. Geological Survey.
Congress has been pushing back against cuts in seismic safety
funding proposed in President Trump’s budget. First, a
congressional panel voted last week to keep funding a West
Coast earthquake early warning system that could have been shut
down under the proposed budget.
Engineers will use UC San Diego’s shake table to subject a
two-story structure to the forces produced by the 6.7
Northridge earthquake to look for ways to design tall wood
buildings that can survive big temblors.
The historically restless Mammoth Lakes area has experienced
more than 150 tiny and small earthquakes over the past week,
including a magnitude 3.0 temblor that hit at 7:13 p.m. on
Monday, says the USGS.
Elected officials from both parties have supported an
earthquake early warning system for the West Coast that, after
years of work, was scheduled to begin its first limited public
operation next year. … One of the system’s biggest proponents
is a Republican congressman who has an influential role in
shaping the budget of the U.S. Geological Survey.
Experts can’t predict earthquakes, but they can warn you that
they’re coming. For a dozen years, West Coast scientists
working with the United States Geological Survey have been
developing an earthquake early warning system — called
ShakeAlert — that could provide anywhere from a few seconds to
a few minutes of warning not only about the shaking that’s
imminent but also about its intensity.
California’s Mediterranean climate, with its wet winters and
dry summers, brings enviable weather to the Golden State but
also earthquakes, according to UC Berkeley research.
In 2015, Steven Horowitz was watching one of the summer’s big
blockbuster action flicks, San Andreas. In the movie, the San
Andreas fault shifts, triggering a magnitude 9.6 earthquake in
San Francisco. Disaster ensues — and for the rest of the movie
we watch as all of the West Coast’s greatest landmarks are
destroyed one by one in an epic, computer-generated spectacle.
New research released this week found that a fault under the
heart of San Diego can produce stronger and more frequent
earthquakes than previously thought. It’s the second study in
recent months pointing to heightened quake risks in the San
Diego area.
President Trump’s budget would eliminate federal funding for an
earthquake early warning system being developed for California
and the rest of the West Coast which, if enacted, probably
would kill the long-planned effort. The budget proposal for the
year ending in September 2018 also seeks to eliminate U.S.
funding for critical tsunami-monitoring stations in oceans and
reduce funds for a next-generation weather forecasting system.
New earthquake sensing stations are being installed in the
ground, software is being improved, and operators are being
hired to make sure the system is properly staffed, Caltech
seismologist Egill Hauksson said at a joint meeting of the
Japan Geoscience Union and American Geophysical Union.
The budget deal reached in Congress this week penciled in $10.2
million for an earthquake early warning system for California
and the rest of the West Coast for the budget year that ends in
September.
The Santa Monica City Council on Tuesday passed the nation’s
most extensive seismic retrofitting effort, which will require
safety improvements to as many as 2,000 buildings suspected to
be vulnerable in an earthquake.
The Newport-Inglewood fault has long been considered one of
Southern California’s top seismic danger zones because it runs
under some of the region’s most densely populated areas, from
the Westside of Los Angeles to the Orange County coast.
After all, California was soaked with ridiculous amounts of
rain this winter and then over the past week, dry, warm
weather, with temps in the 80s recorded in some places, has
baked the state. Could these extreme conditions trigger seismic
activity?
The discovery of missing links between earthquake faults shows
how a magnitude 7.4 earthquake could rupture in the same
temblor underneath Los Angeles, Orange and San Diego counties,
a new study finds.
The Scripps Institution of Oceanography has re-characterized
the Newport-Inglewood and Rose Canyon faults, saying that they
represent a single system that could produce a magnitude 7.3
quake if their offshore segments ruptured. Scientists also say
that the quake could hit 7.4 if the southern section of the
system, which cuts through parts of San Diego, also broke.
Southern California could be overdue for a major earthquake
along the Grapevine north of Los Angeles, according to a
sobering new study by the U.S. Geological Survey. The research
found earthquakes happen there on average every 100 years.
In its annual national earthquake outlook, the U.S. Geological
Survey reported Wednesday that a large portion of Oklahoma and
parts of central California have the highest risk for a
damaging quake this year: between 5 and 12 percent. The outlook
is published in the journal Seismological Research Letters.
Water Education for Latino Leaders is convening a statewide
educational water conference in Sacramento for California local
elected officials.
Local elected officials can make a difference for all
Californians by taking the necessary steps to understand the
dynamic of California water to assure adequate clean water for
our communities, protect our natural resources and our local
economies. WELL’s hope is to facilitate understanding towards
comprehensive long-term water policies that will sustain
California’s economy and quality of life.
The Water Education Foundation is an organizing partner.
San Francisco voters will be asked to allow $350 million to be
spent on a first round of improvements for the city’s crucial
but fragile Embarcadero seawall, officials said Monday.
A swarm of more than 250 small earthquakes have struck since
New Year’s Eve near the California-Mexico border,
causing unease among residents and attention from
scientists.
A magnitude 5 earthquake Wednesday morning jolted The Geysers
region of Northern California, a rural area about 70 miles
north of the San Francisco Bay Area.
