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Aftermath of 1906 San Francisco Earthquake
This hub is about one of the most significant earthquakes in history, “The 1906 San Francisco Earthquake.”
Most of us know what earthquakes are and the disastrous effects they can have depending on their magnitude, location of epicentre, population in that area, buildings and other industries, etc.
Before getting into details of the 1906 San Francisco earthquake, let us briefly look at what earthquakes are and how they occur.
What is an earthquake? How do they occur?
An earthquake is violent shaking of the ground or vibrations caused by rocks or blocks of earth or tectonic plates when they collide or slip past each other at a fault. The plane along which the movement takes place is called the fault plane. It can happen at any time during the day and at any day of the year.
The 1906 San Francisco earthquake happened as a result of a rupture on San Andreas Fault.
Seismogram, Seismographs & Richter scale
How are earthquakes measured?
Earthquakes are recorded using seismographs and the recording is called seismogram. The Seismogram has a heavy weight hanging over a firm base. When the earth shakes, the base of the seismograph shakes, but not the weight and this difference between the shaking part and the stable part is recorded as seismograms.
The size of an earthquake is measured from the seismogram and it is called the magnitude of the earthquake. The magnitude is measured from the amplitude of the seismic waves recorded on the seismogram.
The intensity of the earthquake is also measured by rating them on a Mercalli Intensity Scale.
The 1906 San Francisco earthquake was recorded on a seismograph in Germany.
How a Seismograph Works?
In this video here, you might have a question as to how the hanging weight is stationary! It is due to Inertia.
Inertia is the resistance an object has to the change in its state of motion.
The video is only a demonstration of how a seismograph works and not a real seismograph.
San Andreas Fault
San Andreas Fault:
I have discussed San Andreas fault here briefly, as this earthquake was caused as a result of a rupture on the San Andreas Fault.
San Andreas Fault is a continental transform fault and it forms part of the boundary between the Pacific plate and the North American Plate. Its length is about 800 to 810 miles and roughly ten miles deep and is the most famous fault (a planar crack in a rock along which slipping takes place) in the world. It extends from the Salton Sea in Imperial County to Cape Mendocino in Humboldt County.
The 1906 San Francisco Earthquake:
The 1906 San Francisco Earthquake is also called by other names seen below.
- The Great Quake and Fire
- The Great Shake
- The Great San Francisco Earthquake
1906 San Francisco Earthquake
A brief Outline:
The 1906 San Francisco earthquake is considered to be one of the most significant and worst earthquakes of all times in the United States and is estimated to have registered 8.25 on the Richter scale. This earthquake occurred on the 18th of April, 1906 early in the morning at 5:12 a.m. killing nearly 3000 people (estimate only, real figure still unknown).
The damage due to the shake was severe in many places that were along the fault line rupture. The epicentre of this earthquake was near San Francisco and a majority of the fatalities were in San Francisco while the rest were reported in the nearby areas.
More than 80% of San Francisco was destroyed as a result of the quake and the fire that broke out after the quake and made it
- One of the worst natural disasters in the history of United States
- The greatest loss for life due to a natural disaster in California’s history.
Losses and Damage:
- The cost of damage was estimated to be US$400 million that time (US$8.2 billion in today’s dollars)
- Insured losses were US$235 million that time (US$6 Billion in today’s dollars).
Besides San Francisco, cities of San Jose, Santa Cruz and Santa Rosa also saw huge destruction.
San Andreas Fault
Details of the earthquake (magnitude and geo location):
The estimated magnitude of the earthquake is between 7.7 and 8.25 on the Richter. The rating of the quake on the Rossi-Forel Scale is 9.
(Rossi-Forel Scale is an arbitrary numerical scale of intensity of seismic disturbances ranging from one for a barely perceptible tremor to 10 for an earthquake of the highest intensity)
The earthquake was caused as a result of the rupture on the San Andreas Fault. The length of the fault is about 810 miles and runs along the length of California from Cape Mendocino in the North to Salton Sea in the South. The rupture due to earthquake was along the northern region of the fault for a distance of about 290 miles and the surface displacement (offset) was about 20 to 28 feet (higher in the north 24-28 feet and lower in the south 8 -12 feet).
Photo Gallery - Few pictures of the 1906 San Francisco Quake
A strong foreshock occurred at 5:12 a.m. on the 18th of April 1906 and it was felt in the San Francisco Bay area. After 20 to 25 seconds this was followed by a great earthquake that lasted for about 40 to 45 seconds causing devastating destruction in San Francisco and surrounding cities. The quake was felt from Southern Oregon to South of Los Angeles and extended as far as Central Nevada internally.
Buildings collapsed, gas, sewers and most water lines broke, chimneys broke and fell, and many people were caught under the debris of collapsed buildings as they were still in bed and did not have enough time to leave the buildings. Broken gas lines led to fire that spread across the city of San Francisco. Brick walls collapsed and pavement were arched and fissured. Trees fell to the ground. The fire Chief Dennis T. Sullivan was also a victim of falling debris. Streets, railway lines and other facilities were destroyed and the whole city was reduced to rubble.
The damage caused by the fire was more than that of the quake. There were many aftershocks, in which some of them were severe.
Recent analysis by the United States Geological Survey (USGS) show that the epicentre was near Mussel Rock on the Coast of Daly City which is to the South of San Francisco, evidenced by a tsunami recorded by a tidal gauge at the San Francisco Presidio.
San Francisco Earthquake 1906 - Before and After Journey Down Market
Damage caused by fire:
- More than 30 fires broke out due to rupture of gas mains and they burned uncontrollably destroying 28,000 buildings (500 blocks), which account for more than 90% of the destruction due to earthquake.
- One of the largest fires was started accidentally in a house when a woman was preparing breakfast for her family and it is called the “Ham and Eggs Fire.” This fire burned for 24 hours and destroyed a 30 block area.
- Many fires were started by fire fighters who were not trained in the use of dynamites. They used the wrong dynamites and a result of that fire broke, when they were trying to demolish buildings to bring fire under control. This helped the fire spread and caused more than 50% of the building damage.
- The fire fighters did not have the required supply of water to put the fire off as most of the water mains were broken.
- Many scientific laboratories got burnt in the fire.
- The United States Army played a major role in protecting valuables and guarding buildings. They also helped the fire fighters with setting up dynamites to demolish buildings. They helped with feeding, sheltering and other help for the survivors.
1906 San Francisco
Loss due to the quake:
- Dead – More than 3000
- Homeless people– 225,000
- Buildings destroyed – 28,000
- Monetary loss – More than US$400 million in 1906 dollars
After effects and reconstruction:
Thousands of people were using ferries to cross the bay and move to nearby cities. More than 5000 relief houses were built that accommodated 20,000 people who were displaced. These houses were rented till their houses were rebuilt. Most people moved out within a year and the refugee camp was officially closed on the 30th of June 1908.
Reconstruction plans were immediately drawn to rebuild the city. American Psychologist William James, who was teaching at Stanford at that time, visited the quake site and was impressed by the positivity of the survivors, which he later mentioned in his book “Memories and Studies.” So many other people have also mentioned the fact that the survivors were very positive about the reconstruction of San Francisco to be larger and better than before.
China Town and Chinese Immigrants:
The Chinese population and other poor populations were attempted to be ridden off, but the Chinese rebuilt Chinatown to a modern one. Thousands of Chinese immigrants were able to claim residency and citizenship as their papers were all lost in the quake and fire as the City Hall got completely destroyed.
Nob Hill and Pacific Heights:
Nob Hill was a wealthy area and the mansions in that area were almost completely destroyed in the earthquake, and hence the residents moved to the west where there were cheaper lands and better weather. This also led to the development of the Pacific Heights. Mansions were constructed and most of them were completed by 1915, ready for the Panama-Pacific exposition.
It also celebrated the reconstruction of the city and since then the city memorialised the disaster of the quake at the Lotta’s Fountain (meeting point during disaster where people came searching for loved ones and to exchange information).
Donations by United States except San Francisco
Donation from Foreign Countries
When the news of this disaster spread all over the world, different countries sent in money for relief work. Even individual citizens and companies contributed towards this. Although it was not enough to get people back to their feet, it helped in some way to provide daily meals for them and build some tents.
Donations from United States approximate to a total of $8,228,482