What was cause of San Francisco earthquake in 1989?
What was the cause of the 1989 San Francisco earthquake? The Loma Prieta earthquake was triggered by the mighty San Andreas Fault, where the North American tectonic plate strikes northward while the massive Pacific plate slips southward. During the quake, the epicenter slipped up to 2.3 meters.
What was the damage in the 1989 San Francisco earthquake?
The earthquake killed 62 people and injured approximately 3,700. It caused an estimated $7.4 billion in direct damage and about $2.6 billion in uninsured property damage and in secondary economic impacts. Did the 1989 San Francisco earthquake cause a tsunami?
How many people died in the San Francisco earthquake in 1989?
On October 17, 1989, a magnitude 6.9 earthquake hit the San Francisco Bay Area, killing 67 people and causing more than $5 billion in damages. Despite the fact that the disaster was one of the most...
Why did the 1989 San Francisco earthquake happen?
What caused the 1989 earthquake in San Francisco? On October 17, 1989, the central coast of California was jolted by the Loma Prieta earthquake. The Loma Prieta earthquake was triggered by the mighty San Andreas Fault, where the North American tectonic plate strikes northward while the massive Pacific plate slips southward.
What scale was the earthquake in San Francisco 1989?
magnitude 6.9On October 17, 1989, the San Francisco Bay area was jolted by the Loma Prieta earthquake. The quake's epicenter was near Loma Prieta Peak in the Santa Cruz Mountains. The magnitude 6.9 quake was the most powerful the state had experienced in several years.
Did the Golden Gate Bridge collapse in 1989?
Loma Prieta Earthquake, October 17, 1989 Although the Golden Gate Bridge suffered no observed damage from the Loma Prieta quake, since the epicenter was located some 60 miles to the south, the earthquake became a catalyst for the extensive seismic retrofit program that the historic structure is undergoing today.
What magnitude was the 1906 earthquake compared to the San Francisco earthquake of 1989?
And yet, 83 years prior, an even larger earthquake struck the Bay Area and lasted much longer. The 1989 earthquake measured between 6.9 and 7.1 on the Richter Scale and the 1906 earthquake is estimated to measure between 7.9 and 8.3. To put it in perspective, the 1906 quake released 16-times more energy than in 1989.
How many people died in the 1989 quake?
63 killed1989 Loma Prieta earthquakeImage of collapsed Cypress freeway structure in Oakland, CaliforniaSanta Cruz Oakland SalinasLandslides1,000–4,000Foreshocks5.3 ML June 27, 1988 5.4 ML August 8, 1989Casualties63 killed, 3,757 injured15 more rows
What was the strongest earthquake in California?
magnitude 6.0 earthquakeDozens of aftershocks followed, including some of magnitude 4.0 or greater. The magnitude 6.0 earthquake was the largest to hit the area since the magnitude 6.1 quake in 1994. Some viewers shared their reaction to the recent earthquake, many comparing it to the 1989 Loma Prieta earthquake in San Francisco.
What is the largest earthquake ever recorded in California?
California's Largest Recorded Earthquakes Since 1800, Ranked by MagnitudeMagnitudeDateLocation7.9Jan. 9, 1857Fort Tejon7.8April 18, 1906San Francisco7.4Mar. 26, 1872Owens Valley7.4Nov. 8, 1980W. of Eureka*12 more rows
What was the largest earthquake in San Francisco?
On April 18, 1906, at 5:13 a.m., an earthquake estimated at close to 8.0 on the Richter scale strikes San Francisco, California, killing an estimated 3,000 people as it topples numerous buildings.
What is the largest earthquake ever recorded?
Mw 9.5 earthquakeOn May 22, 1960 a great Mw 9.5 earthquake, the largest earthquake ever instrumentally recorded, occurred off the coast of southern Chile. This earthquake generated a tsunami that was destructive not only along the coast of Chile, but also across the Pacific in Hawaii, Japan, and the Philippines.
How large was the 1989 Loma Prieta quake on the Richter Scale?
6.9Caused by a slip along the San Andreas Fault, the quake lasted 10–15 seconds and measured 6.9 on the moment magnitude scale, or 6.9 on the open-ended Richter Scale. The quake killed 63 people throughout northern California, injured 3,757 and left some 3,000-12,000 people homeless.
Did the 1989 Loma Prieta earthquake cause a tsunami?
Abstract. We investigated the tsunami recorded at Monterey, California, during the 1989 Loma Prieta earthquake (MW=6.9). The first arrival of the tsunami was about 10 min after the origin time of the earthquake.
How long did the San Francisco earthquake last?
45 to 60 secondsThe great earthquake broke loose some 20 to 25 seconds later, with an epicenter near San Francisco. Violent shocks punctuated the strong shaking which lasted some 45 to 60 seconds.
Was there a 7.1 earthquake in California today?
A magnitude 7.1 earthquake struck southern California on July 5, 2019 at 8:20 p.m. local time (July 6 at 03:20 UTC). This event was centered near the July 4, 2019 magnitude 6.4 earthquake.
What was the magnitude of the San Francisco earthquake?
San Francisco Earthquake of 1989. On October 17, 1989, a magnitude 6.9 earthquake hit the San Francisco Bay Area, killing 67 people and causing more than $5 billion in damages. Author:
How many people died in the San Francisco earthquake?
On October 17, 1989, a magnitude 6.9 earthquake hit the San Francisco Bay Area, killing 67 people and causing more than $5 billion in damages. Despite the fact that the disaster was one of the most powerful and destructive quakes ever to hit a populated area of the United States, the death toll was relatively small.
Why is the San Francisco earthquake called the Loma Prieta earthquake?
The disaster is known as both as the San Francisco-Oakland earthquake and the Loma Prieta earthquake because it was centered near Loma Prieta Peak in the Santa Cruz Mountains. On October 17, the Bay Area was buzzing about baseball. The Oakland Athletics and San Francisco Giants, both local teams, had reached the World Series.
How much damage did the Watsonville earthquake do?
More than 30 percent of Watsonville’s downtown and 1 in 8 houses were destroyed.Total damages from the earthquake were estimated at more than $5 billion. In the quake’s aftermath, San Francisco and other communities enacted strict regulations requiring unreinforced masonry buildings to be retrofitted.
When was the Bay Bridge opened?
The San Francisco-Oakland Bay Bridge opened to traffic in November 1936, six months before the Golden Gate Bridge. 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.
What year was the Loma Prieta earthquake?
The 1989 Loma Prieta Earthquake. Revisiting the 1989 Loma Prieta earthquake serves as an important reminder to all residents of California that the geologic processes responsible for creating the beautiful natural landscape we enjoy can sometimes occur suddenly and violently so it’s important to be prepared. The anniversary of the Loma Prieta ...
Where was the magnitude of the Loma Prieta earthquake?
Magnitude established at 6.9 after consultation with monitoring stations around the world. The Loma Prieta quake was felt as far away as San Diego and western Nevada.
What is the magnitude of an earthquake?
Magnitude is a measure of an earthquake's size, but rather than being a direct measure of the level of ground shaking, it is a measurement of the strength of the seismic sound waves given off by the earthquake. A magnitude 8 earthquake radiates 30 times more energy of a magnitude 7 and 900 times the energy of a magnitude 6. Strong ground shaking for a magnitude 7 quake typically lasts about 15 seconds. It lasts a minute in a magnitude 8.
How long does a magnitude 8 earthquake last?
Strong ground shaking for a magnitude 7 quake typically lasts about 15 seconds. It lasts a minute in a magnitude 8.
What was the most significant damage to the Bay Bridge?
The most notable damage included the collapse of the elevated Cypress Structure section of Interstate 880 in Oakland, the collapse of a section of roadbed on the Bay Bridge, and extensive damage to downtown Santa Cruz and San Francisco's Marina District. The Bay Bridge was unusable for a month.
What is the boundary between the North American plate and the Pacific plate?
The San Andreas Fault is the boundary between the North American plate and the Pacific plate. Land west of the fault has been moving to the northwest relative to land on the east at an average rate of 2 inches per year for millions of year. This motion typically occurs in sudden jumps during large earthquakes.
What happened in 1989 San Francisco earthquake?
In the 1989 earthquake, the water-saturated unconsolidated mud, sand, and rubble suffered liquefaction, and the earthquake's vertical shock waves rippled the ground more severely. At the intersection of Beach and Divisadero Streets in San Francisco, a natural gas main rupture caused a major structure fire.
When did the San Andreas earthquake occur?
The Loma Prieta segment of the San Andreas Fault System had been relatively inactive since the 1906 San Francisco earthquake (to the degree that it was designated a seismic gap) until two moderate foreshocks occurred in June 1988 and again in August 1989.
How many people died in the Loma Prieta earthquake?
63 killed, 3,757 injured. The 1989 Loma Prieta earthquake occurred on California's Central Coast on October 17 at 5:04 p.m. local time. The shock was centered in The Forest of Nisene Marks State Park in Santa Cruz County, approximately 10 mi (16 km) northeast of Santa Cruz on a section of the San Andreas Fault System and was named for ...
What is the most studied fault in California?
The history of earthquake investigations in California has been largely focused on the San Andreas Fault System , due to its strong influence in the state as the boundary between the Pacific Plate and the North American Plate; it is the most studied fault on Earth. Andrew Lawson, a geologist from the University of California, Berkeley, had named the fault after the San Andreas Lake (prior to the occurrence of the 1906 San Francisco earthquake) and later led an investigation into that event. The San Andreas Fault ruptured for a length of 290 mi (470 km) during the 1906 shock, both to the north of San Francisco and to the south in the Santa Cruz Mountains region. Several long term forecasts for a large shock along the San Andreas Fault in that area had been made public prior to 1989 (the event and its aftershocks occurred within a recognized seismic gap) but the earthquake that transpired was not what had been anticipated. The 1989 Loma Prieta event originated on an undiscovered oblique-slip reverse fault that is located adjacent to the San Andreas Fault.
What station was on the air after the earthquake?
About an hour and 40 minutes after the quake, Fox affiliate KTVU resumed broadcasting, with their news anchors, Dennis Richmond and Elaine Corral reporting from the station's parking lot. KCBS-AM ( CBS News Radio) switched immediately to backup power and managed to stay on air despite a subsequent generator failure.
Where did the ML 5.3 earthquake occur?
The ML 5.3 June 1988 and the M L 5.4 August 1989 events also occurred on previously unknown oblique reverse faults and were within 3 mi (4.8 km) of the M6.9 Loma Prieta mainshock epicenter, near the intersection of the San Andreas and Sargent faults. Total displacement for these shocks was relatively small (approximately 4 in (100 mm) of strike-slip and substantially less reverse-slip) and although they occurred on separate faults and well before the mainshock, a group of seismologists considered these to be foreshocks due to their location in space and time relative to the main event. Each event's aftershock sequence and effect on stress drop was closely examined, and their study indicated that the shocks affected the mainshock's rupture process. Following the August 8, 1989 shock, in anticipation of an upcoming large earthquake, staff at the University of California, Santa Cruz deployed four accelerometers in the area, which were positioned at the UCSC campus, two residences in Santa Cruz, and a home in Los Gatos. Unlike other nearby (high gain) seismographs that were overwhelmed (driven off scale) by the large magnitude mainshock, the four accelerometers captured a useful record of the main event and more than half an hour of the early aftershock activity.
What was the worst earthquake in Oakland?
The worst disaster of the earthquake was the collapse of the double-deck Cypress Street Viaduct of Interstate 880 in West Oakland. The failure of a 1.25-mile (2.0 km) section of the viaduct, also known as the "Cypress Structure" and the "Cypress Freeway", killed 42 and injured many more.
Where
- The epicenter was on the San Andreas fault roughly 56 miles south of San Francisco and 10 miles northeast of Santa Cruz, near Mt. Loma Prieta in the Santa Cruz Mountains. The focal depth was 11 miles (typical California earthquake focal depths are 4 to 6 miles). Loma Prleta ruptured the southernmost 30 miles of the break that caused the 1906 San Fr...
How Big
- Magnitude established at 6.9 after consultation with monitoring stations around the world. The Loma Prieta quake was felt as far away as San Diego and western Nevada.
Aftershocks
- A magnitude 5.2 aftershock occurred approximately 2.5 minutes after the main shock. In the week following Loma Prieta, 20 aftershocks magnitude 4.0 or greater and more than 300 of magnitude 2.5 or greater were recorded. Thousands of aftershocks were recorded. The aftershock zone stretched 25 miles, from north of Los Gatos near Highway 17 to south of Watsonville near High…
Damage
- Damage and business interruption estimates reached as high as $10 billion, with direct damage estimated at $6.8 billion. 18,306 houses were damaged and 963 were destroyed. 2,575 businesses were damaged and 147 were destroyed. The most notable damage included the collapse of the elevated Cypress Structure section of Interstate 880 in Oakland, the collapse of …
Warning Signs
- Geologists had forecast a major earthquake in this area based on historical data, especially the lack of a major seismic event along the San Andreas fault since 1906 -- the 8.3 San Francisco earthquake. In the 83 years prior to the 1906 quake, seven damaging earthquakes of magnitude 6.5 or greater occurred. Only two have occurred since the San Francisco earthquake. Several 5.…
The Fault
- The San Andreas Fault is the boundary between the North American plate and the Pacific plate. Land west of the fault has been moving to the northwest relative to land on the east at an average rate of 2 inches per year for millions of year. This motion typically occurs in sudden jumps during large earthquakes. The Pacific plate moved 6.2 feet to the northwest and 4.3 feet upward over t…
Magnitude Defined
- Magnitude is a measure of an earthquake's size, but rather than being a direct measure of the level of ground shaking, it is a measurement of the strength of the seismic sound waves given off by the earthquake. A magnitude 8 earthquake radiates 30 times more energy of a magnitude 7 and 900 times the energy of a magnitude 6. Strong ground shaking for a magnitude 7 quake typi…
What If
- As devastating as Loma Prieta was, a magnitude 7.5 earthquake on the Hayward Fault in the East Bay could do $65 billion in damage.