Much of the Marina is built on former landfill, and is susceptible to soil liquefaction during strong earthquakes. This phenomenon caused extensive damage to the entire neighborhood during the 1989 Loma Prieta earthquake . Damage to the Marina District following the 1989 Loma Prieta earthquake.
Full Answer
Why was the Marina District vulnerable to earthquakes?
Much of the Marina is built on former landfill, and is susceptible to soil liquefaction during strong earthquakes. This phenomenon caused extensive damage to the entire neighborhood during the 1989 Loma Prieta earthquake.
Why was damage in the Marina District of San Francisco most extensive?
The Marina District was the part of San Francisco most heavily damaged in the 1989 Loma Prieta earthquake because it was built on uncompacted, sandy ground in an area with a shallow water table.
Why most of the damages in the Loma Prieta earthquake was concentrated in the Marina District?
During the 1989 Loma Prieta Earthquake, the soils underlying the Marina District amplified the ground motion as in 1906 and caused the liquefaction of the superficial sandy materials that were used to fill the old lagoon in 1915. Damage in the Marina District was concentrated along the edges of the old lagoon.
Why is San Francisco so vulnerable to earthquakes?
San Francisco is very vulnerable to earthquakes. Its three notable faults, covered below, are right-lateral strike-slip faults. This is a type of shearing force where the right block moves toward the fault and the left block moves away. Millions of Bay Area residents live near active fault zones.
Why was the Marina district so heavily damaged?
San Francisco's Marina district suffered extensive damage. Built on an area where there was no underlying bedrock, the liquefaction of the ground resulted in the collapse of a number of structures. Additionally, gas mains and pipes burst, sparking fires.
What's the worst earthquake in California?
In 1994, a 6.7 earthquake hit near Northridge, Calif. Its peak G-force acceleration was the highest ever recorded with modern instrumentation in a North American city. In 1989, a 6.9 earthquake hit Loma Prieta, Calif. It felled Bay Area freeway interchanges, interrupted a World Series and caused $10 billion in damage.
Why was the Marina District of San Francisco heavily damaged in the 1906 earthquake and the 1989 Loma Prieta quake quizlet?
There is total damage; objects are thrown into the air. Why was the Marina District of San Francisco heavily damaged in the 1906 earthquake and the 1989 Loma Prieta quake? Liquefaction and foundation failures were common.
What made the 1989 Loma Prieta earthquake so much worse in the Marina District in San Francisco?
San Francisco's Marina district was particularly hard hit because it had been built on filled land (comprising loose, sandy soil), and the unreinforced masonry buildings in Santa Cruz (many of which were 50 to 100 years old) failed completely.
Which places suffered the most damage as a result of the Loma Prieta earthquake?
The Nimitz Freeway, in Oakland, California, experienced catastrophic damage during the 1989 Loma Prieta Earthquake. Entire sections of the upper deck of the freeway collapsed directly on the lower deck, instantly crushing more than two dozen cars and their occupants.
Why is California so vulnerable to earthquakes?
Since the formation of the San Andreas Fault system 25-30 million years ago, the juxtaposition of the Pacific and North American plates has formed many faults in California that accommodate lateral motion between the plates.
Why is California vulnerable to earthquakes?
The driving force of earthquakes in California is movement along the San Andreas Fault and the many associated faults within the San Andreas Fault System that form the tectonic boundary between the Pacific and North American tectonic plates.
Where along a fault are you most likely to see a large earthquake quizlet?
Gravitational attraction between the Moon and the Earth. Where along a fault are you most likely to see a large earthquake? The area on the fault that has not moved in a long time. Not all earthquakes are preceded by foreshocks.
Why was the 1906 San Francisco earthquake so destructive?
The quake was caused by a slip of the San Andreas Fault over a segment about 275 miles long, and shock waves could be felt from southern Oregon down to Los Angeles. San Francisco's brick buildings and wooden Victorian structures were especially devastated.
What was the damage of the San Francisco earthquake?
More than 3,000 people perished and more than 28,000 buildings were destroyed in the disaster. Additionally, some 250,000 of San Francisco's residents were made homeless. Damages were estimated at around $500 million (in 1906 dollars).
What was the most damaging factor in the 1906 San Francisco earthquake?
Despite the devastation caused by the earthquake, most of the damage to the city was caused by another factor: fire. According to Allen, shaking from the earthquake knocked over wood-burning stoves, the main source of heat for homes at the time.
What was the worst natural disaster in San Francisco?
Earthquakes On April 18, 1906, a 7.9 magnitude earthquake struck the coast of Northern California and absolutely devastated San Francisco. It is estimated that 80% of the city was destroyed by the earthquake and subsequent fires. Over 3,000 people lost their lives that day.
What was the area of the Marina District in the 19th century?
The area in the 19th century prior to the 1906 earthquake consisted of bay shallows, tidal pools, sand dunes, and marshland similar to nearby Crissy Field. Human habitation and development came in the mid to late 19th century in the form of a sandwall and ...
What happened to the Marina in Loma Prieta?
This phenomenon caused extensive damage to the entire neighborhood during the 1989 Loma Prieta earthquake .
What is the neighborhood of San Francisco?
Neighborhood of San Francisco in California, United States. Marina District. Neighborhood of San Francisco. The Palace of Fine Arts, a replica of the one built for the Panama–Pacific International Exposition, is a landmark of the Marina District. Nickname (s):
Where is the Marina District?
Area codes. 415/628. The Marina District is a neighborhood located in San Francisco, California. The neighborhood sits on the site of the 1915 Panama–Pacific International Exposition, staged after the 1906 San Francisco earthquake to celebrate the reemergence of the city. Aside from the Palace of Fine Arts (POFA), ...
When did humans start habitation?
Human habitation and development came in the mid to late 19th century in the form of a sandwall and of a road from the nearby Presidio to Fort Mason. Most of the sand dunes were leveled out and a hodgepodge of wharves and industrial plants was built extending from what is now Laguna Street to Steiner Street.
Where is the Academy of Art University?
San Francisco's Academy of Art University has a campus housing building at the Southern edge of the neighborhood on Lombard Street.
When was Lombard Street redeveloped?
This major redevelopment was completed in the 1920s. In the 1930s, with the completion of the nearby Golden Gate Bridge, Lombard Street (now Highway 101) was widened, and soon developed into a strip of roadside motels .
What is the most significant evidence of liquefaction in the Marina District?
The most significant evidence that liquefaction had occurred in the Marina District was from the sand boils. Throughout the entire district, the liquefied sand was under such significant pressure from the shaking that it erupted through the ground surface. The composition of these sand boils was important in understanding which composition of soil and type of hydraulic fill underwent the most significant amount of liquefaction. Most of the sand boils were “fine grained gray sand, commonly containing shells.” [6] This would indicate that the post-1906 earthquake fill, which was dredged from the Bay floor, underwent the most intense liquefaction in the area. Fewer sand boils were composed of larger brown sand and contained pieces of charred wood. [7] The larger grain size and brown color indicates that these sand boils came from the dune sand placed during the original filling of the district.
Why was the Marina District under water?
The reason the Marina District underwent such high levels of liquefaction during the Loma Prieta earthquake can be traced back to its soil composition. Prior to the late nineteenth century, much of the modern-day Marina District was underwater in the San Francisco Bay. Several stages of fill were placed in this area, beginning around the 1870s to create the Marina District. Much of the fill consisted of “uncompacted fine sands and silty sands.” [4] The first fill stage occurred from 1870 to 1900 using dune sand, and “consisted primarily of placement of loosely dumped fill around the perimeter of the small Marina bay and in the perimeter marshes.” [4] A seawall was also constructed during this phase to create an enclosed harbor on the shore of the district. [4]
What is the blow count of Loma Prieta?
Standard penetration tests (SPT) of the Marina District showed a blow count range of N1 roughly equal to seven to twelve blows per foot in the fill zones. [4] Natural alluvial deposits in surrounding regions showed an N1 range of fifteen to twenty-five and higher blows per foot. [4] These natural deposits with higher blow counts did not liquefy during the earthquake. The relatively low blow count in the liquefaction zones indicates that decreasing density and stiffness in soils correlates with a higher liquefaction potential.
What type of damage did liquefaction cause?
Another type of destruction attributed to liquefaction was the cracks, settlement, and lateral movement that occurred in the pavement and sidewalks. The size and shape of the cracks in the pavement indicated how the subsurface soil behaved when it liquefied. Lateral cracks in the pavement indicated shearing induced by the horizontal displacement of liquefied soil. [7] In other areas, the liquefied soils underwent significant compression, which resulted in the sidewalks being thrust up into tent-like shapes. [7] Most of the cracks occurred in the areas of hydraulic fill, and generally showed less than one hundred millimeters in settlement or lateral movement. [7] Additionally, the largest of the cracks were located along the border between the 1912 hydraulic fill zone and the older fill and beach deposit zones. [7] Thus, the higher degree of liquefaction in the hydraulic fill relative to the older fill and beach deposits lead to damaging differential settlement of the pavement. This means that the variable soil composition of the Marina District played a significant role in the liquefaction damage that occurred.
What is liquefaction in San Francisco?
Liquefaction is a serious hazard that much of the San Francisco Bay Area faces. To determine the areas at risk for liquefaction, one must look at the soil composition and saturation level. Liquefaction is most likely to occur in fully saturated sandy soils. [1] During earthquake conditions, the shaking of the ground causes the soil to behave like a very viscous liquid, and creates a large and sudden reduction in the soil’s ability to support foundations of structures. [1] Liquefied soils also pose a great risk to dams and retaining walls as they apply a high pressure against the structure, causing them to tilt and even slide. [1]
What happens to the soil when it shakes?
When the soil liquefies to this degree, it has the ability to flow and can no longer support the load of structures on top of it. This can cause serious damage to infrastructure, as seen in San Francisco Marina District during the 1989 Loma Prieta earthquake.
Where was the Loma Prieta earthquake?
[6] The epicenter was located on the San Andreas fault line in the Santa Cruz Mountains, over sixty miles south of the Marina District. [6] The shaking lasted roughly twenty seconds and had a Magnitude of 6.9. Thousands of aftershocks occurred over the following week. [6] It is estimated that the earthquake caused upwards of ten billion dollars in damage, and remains one of the costliest single natural disasters in United States history. [6] The earthquake caused significant liquefaction in the Marina District, which caused sand boils, lateral spreading, settlement, bearing failures, pavement damage, foundation damage, and damage to buried utilities throughout the district. [4]
How many people died in the Nepal earthquake?
Scientists are now analysing seismic data in an effort to understand the strongest earthquake to hit Nepal in more than 80 years, which has left more than 3,000 people dead.
How deep is the clay in Kathmandu?
The heavily populated Kathmandu valley has a 300-metre-deep layer of clay beneath it.
What causes solid ground to turn into quicksand?
This occurs when vibrations cause solid ground to turn in to something like quicksand.
Which plate is Nepal on?
Nepal straddles the fault line between two of these plates; the Indian and the Eurasian plates. These are being forced up against and under each other, at a rate of about 5cm each year.
Is Nepal a poor country?
Nepal is one of the poorest countries in the world and little of this earthquake preparation work had been done.
Can buildings be swallowed by the Earth?
As a result, buildings and roads can be swallowed by the earth.
Overview
The Marina District is a neighborhood located in San Francisco, California. The neighborhood sits on the site of the 1915 Panama–Pacific International Exposition, staged after the 1906 San Francisco earthquake to celebrate the reemergence of the city. Aside from the Palace of Fine Arts (POFA), all other buildings were demolished to make the current neighborhood. The Marina curr…
Location
The area is bounded to the east by Van Ness Avenue and Fort Mason; on the west by Lyon Street and the Presidio National Park; on the south by Cow Hollow and Lombard St, which bisects the southern edge of the Marina District. The northern half of the Marina is a shoreline of the San Francisco Bay, and features the Marina Green, a park adjacent to the municipal boat marina from which the neighborhood takes its name.
History
The area in the 19th century prior to the 1906 earthquake consisted of bay shallows, tidal pools, sand dunes, and marshland similar to nearby Crissy Field. Human habitation and development came in the mid to late 19th century in the form of a sandwall and of a road from the nearby Presidio to Fort Mason. Most of the sand dunes were leveled out and a hodgepodge of wharves and industri…
Attractions
The neighborhood is most famous for the Palace of Fine Arts, which until 2013 housed the Exploratorium, a hands-on science museum and children's educational center, and which takes up much of the western section of the neighborhood. The Palace is the only building left standing in its original location within the 1915 Exposition fairgrounds. The grounds around the Palace are a year-round attraction for tourists and locals, and are used as a location for weddings and weddi…
Government and infrastructure
The San Francisco Police Department Northern Station serves the Marina District.
Education
It is in the San Francisco Unified School District (SFUSD) and is within the Sherman Elementary School attendance area. As of 2018 Sherman has about 20 teachers.
See also
• A16
External links
• "Strangers in the night – Bars, cheap sex, and boozy anthropology". San Francisco Bay Guardian.
• Google maps