Misplaced Pages

#668331

85-471: In 1988 and 1989, two earthquakes at M =5.3 and 5.4 respectively occurred at Lake Elsman that transferred stress that led to the 1989 M =6.9 1989 Loma Prieta earthquake . Construction of the Austrian Dam was completed in 1950. Beneath the reservoir are the remains of the settlements of Austrian Gulch and Germantown. The dam is more than 900 feet (270 m) long and 180 feet (55 m) high. The dam

170-459: A crack down the front of the building. Many homes were dislodged if they were not bolted to their foundations. There were structural failures of twin bridges across Struve Slough near Watsonville. In Moss Landing, the liquefaction destroyed the causeway that carried the Moss Beach access road across a tidewater basin, damaged the approach and abutment of the bridge linking Moss Landing spit to

255-566: A crucial link to rescue workers. Widespread search operations were organized to find possible victims inside the remains of fallen structures. As many as six teams of dogs and their handlers were at work identifying the large number of damaged buildings that held no victims. The quake claimed one life in Watsonville : a driver who collided with panicked horses after they escaped their collapsed corral. In other Santa Cruz and Monterey county locations such as Boulder Creek and Moss Landing ,

340-476: A large slide and one person was killed by a rockfall along the coast. Other areas with certain soil conditions were susceptible to site amplification due to the effects of liquefaction , especially near the shore of San Francisco Bay (where its effects were severe in the Marina District ) and to the west of the epicenter near rivers and other bodies of water. Minor lateral spreading was also seen along

425-476: A number of structures were damaged, with some knocked off of their foundations. Many residents slept outside their homes out of concern for further damage from aftershocks, of which there were 51 with magnitudes greater than 3.0 in the following 24 hours, and 16 more the second day. The earthquake damaged several historic buildings in the Old Town district of Salinas , and some were later demolished. Damage to

510-668: A section of the double-deck Nimitz Freeway in Oakland was the site of the largest number of casualties for the event, but the collapse of human-made structures and other related accidents contributed to casualties occurring in San Francisco, Los Gatos , and Santa Cruz. The history of earthquake investigations in California has been largely focused on the San Andreas Fault system because of its strong influence in

595-453: A substantial increase in noise was measured in the frequency range 0.01–10 Hz. The measurement instrument was a single-axis search-coil magnetometer that was being used for low frequency research. Precursor increases of noise apparently started a few days before the earthquake, with noise in the range 0.01–0.5 Hz rising to exceptionally high levels about three hours before the earthquake. The Fraser-Smith et al. report remains one of

680-531: A thing. McCarver: I guess Dave Parker ... Michaels: Well, heh, I don't know if we're on the air or not, and I'm not sure I care at this particular moment but we are. Well, folks, that's the greatest open in the history of television! Bar none! McCarver: Opened with a bang! Pacific plate The Pacific plate is an oceanic tectonic plate that lies beneath the Pacific Ocean . At 103 million km (40 million sq mi), it

765-816: Is a transform boundary with the North American plate along the San Andreas Fault , and a boundary with the Cocos plate . The south-eastern side is a divergent boundary with the Nazca plate forming the East Pacific Rise . The southern side is a divergent boundary with the Antarctic plate forming the Pacific–Antarctic Ridge . The western side is bounded by the Okhotsk microplate at

850-536: Is located adjacent to the San Andreas Fault. Since many forecasts had been presented for the region near Loma Prieta, seismologists were not taken by surprise by the October 1989 event. Between 1910 and 1989 there were 20 widely varying forecasts that were announced, with some that were highly specific, covering multiple aspects of an event, while others were less complete and vague. With a M6.5 event on

935-494: Is not seen in the Santa Cruz Mountains. Three scenarios were presented that might explain this disparity. The first is that the geometry of the San Andreas Fault goes through a transition every several thousand years. Secondly, slip type could vary from event to event. And lastly, the 1989 event did not occur on the San Andreas Fault. While the effects of a four-year drought limited the potential of landslides ,

SECTION 10

#1732775634669

1020-697: Is the largest tectonic plate. The plate first came into existence as a microplate 190 million years ago, at the triple junction between the Farallon , Phoenix , and Izanagi plates . The Pacific plate subsequently grew to where it underlies most of the Pacific Ocean basin. This reduced the Farallon plate to a few remnants along the west coast of the Americas and the Phoenix plate to a small remnant near

1105-750: The Central Coast of California. 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 the nearby Loma Prieta Peak in the Santa Cruz Mountains . With an M w magnitude of 6.9 and a maximum Modified Mercalli intensity of IX ( Violent ),

1190-874: The Drake Passage , and destroyed the Izanagi plate by subduction under Asia. The Pacific plate contains an interior hot spot forming the Hawaiian Islands . The north-eastern side is a divergent boundary with the Explorer plate , the Juan de Fuca plate and the Gorda plate forming respectively the Explorer Ridge , the Juan de Fuca Ridge and the Gorda Ridge . In the middle of the eastern side

1275-945: The Kuril–Kamchatka Trench and the Japan Trench . The plate forms a convergent boundary by subducting under the Philippine Sea plate creating the Mariana Trench , has a transform boundary with the Caroline plate , and has a collision boundary with the North Bismarck plate . In the south-west, the Pacific plate has a complex but generally convergent boundary with the Indo-Australian plate , subducting under it north of New Zealand forming

1360-548: The Salinas River rail bridge and subsequent repairs led to reduced traffic on the Monterey Branch Line , which contributed to the discontinuance of freight rail services in western Monterey County. The San Francisco–Oakland Bay Bridge suffered severe damage, as a 76-by-50-foot (23 m × 15 m) section of the upper deck on the eastern cantilever side fell onto the deck below. The quake caused

1445-586: The State office of Emergency Services issued (for the first time in Bay Area history) short term advisories for a possible large earthquake, which meant there was "a slightly increased likelihood of an M6.5 event on the Santa Cruz Mountains segment of the San Andreas fault". The advisories following the two Lake Elsman events were issued in part because of the statements made by WGCEP and because they were two of

1530-749: The Tonga Trench and the Kermadec Trench . The Alpine Fault marks a transform boundary between the two plates, and further south the Indo-Australian plate subducts under the Pacific plate forming the Puysegur Trench . The southern part of Zealandia , which is to the east of this boundary, is the plate's largest block of continental crust. Hillis and Müller are reported to consider the Bird's Head plate to be moving in unison with

1615-524: The Transbay Tube between the date of the earthquake and December 3 that same year. 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. Built in

1700-463: 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

1785-520: The Asian oceanic trenches. The oldest part disappearing by way of the plate tectonics cycle is early- Cretaceous (145 to 137 million years ago). The Pacific plate originated at the triple junction of the three main oceanic plates of Panthalassa , the Farallon , Phoenix , and Izanagi plates , around 190 million years ago. The plate formed because the triple junction had converted to an unstable form surrounded on all sides by transform faults , due to

SECTION 20

#1732775634669

1870-647: The Cypress Street Viaduct in Oakland) the intensity of the shaking was more severe and lasted longer. The strong motion records also allowed for the causative fault to be determined – the rupture was related to the San Andreas Fault System. While a Mercalli Intensity of VIII ( Severe ) covered a large swath of territory relatively close to the epicenter (including the cities of Los Gatos, Santa Cruz, and Watsonville ) farther to

1955-527: The East Bay, and near the shore of Monterey Bay , where a non-destructive tsunami was also observed. Because it happened during a national live broadcast of the 1989 World Series , the annual championship series of Major League Baseball , taking place between Bay Area teams San Francisco Giants and the Oakland Athletics , it is sometimes referred to as the "World Series earthquake" , with

2040-516: The Emergency Broadcast System to the public after the quake because the engineering department at KNBR experienced major technical malfunctions and difficulties. The malfunctions during the aftermath of the earthquake caused confusion as to whether an earthquake would cause the Emergency Broadcast System to activate. KNBR began using an emergency generator, hooking up the signal from a command center right after their nearby studio

2125-424: The Oakland side of the bridge to shift 7 in (18 cm) to the east, and caused the bolts of one section to shear off, sending the 250-short-ton (230 t; 500,000 lb; 226,800 kg) section of roadbed crashing down like a trapdoor. Traffic on both decks came to a halt, blocked by the section of the roadbed. Police began unsnarling the traffic jam, telling drivers to turn their cars around and drive back

2210-560: The Pacific plate, but Bird considers them to be unconnected. The northern side is a convergent boundary subducting under the North American plate forming the Aleutian Trench and the corresponding Aleutian Islands (see also: Aleutian Arc ). The Pacific plate is almost entirely oceanic crust , but it contains some continental crust in New Zealand, Baja California , and coastal California . The Pacific plate has

2295-575: The San Juan Bautista segment, or an M7 event on the San Francisco Peninsula segment, United States Geological Survey (USGS) seismologist Allan Lindh's 1983 forecasted rupture length of 25 miles (40 km) (starting near Pajaro Gap, and continuing to the northwest) for the San Juan Bautista segment nearly matched the actual rupture length of the 1989 event. An updated forecast was presented in 1988, at which time Lindh took

2380-585: The Santa Cruz Historic Building Survey. The four oldest were built in 1894, the five oldest withstood the 1906 San Francisco earthquake. Immediately, a number of civilians began to free victims from the rubble of Ford's Department Store and the Santa Cruz Coffee Roasting Company – both buildings had collapsed inward on customers and employees alike. Two police officers crawled through voids in

2465-469: The Santa Cruz Mountains was about 15 seconds, but strong ground motion recordings revealed that the duration of shaking was not uniform throughout the affected area (because of different types and thicknesses of soil ). At sites with rocky terrain, the duration was shorter and the shaking was much less intense, and at locations with unconsolidated soil (like the Marina District in San Francisco or

2550-661: The Santa Cruz Mountains, pieces of concrete fell from a parking structure at the Sunnyvale Town Center , a two-level shopping mall in Santa Clara County. More moderate damage resulted from the August 8, 1989, shock (intensity VII, Very strong ) when chimneys were toppled in Cupertino , Los Gatos, and Redwood Estates . Other damage included cracked walls and foundations and broken underground pipes. At

2635-425: The affected area, many people had left work early or were staying late to participate in after work group viewings and parties. As a consequence the normally crowded freeways contained unusually light traffic. If traffic had been normal for a Tuesday rush hour , injuries and deaths would certainly have been higher. The initial media reports failed to take into account the game's effect on traffic and initially estimated

Lake Elsman - Misplaced Pages Continue

2720-630: The cable cars. Amtrak intercity rail service into Oakland from the California Zephyr continued, but the Coast Starlight was temporarily suspended north of Salinas because of damage to the Southern Pacific 's Coast Line . The earthquake changed the Bay Area's automobile transportation landscape. Not only did the quake force seismic retrofitting of all Bay Area bridges, it caused enough damage that some parts of

2805-403: The championship games of the year being referred to as the "Earthquake Series". Rush-hour traffic on the Bay Area freeways was much lighter than normal because the game, being played at Candlestick Park in San Francisco, was about to begin, and this may have prevented a larger loss of life, as several of the Bay Area's major transportation structures suffered catastrophic failures. The collapse of

2890-681: The collapse of buildings along the Pacific Garden Mall in Santa Cruz, and five people were killed in the collapse of a brick wall on Bluxome Street in San Francisco. When the earthquake hit, the third game of the 1989 World Series baseball championship was about to begin. Because of the unusual circumstance that both of the World Series teams (the San Francisco Giants and Oakland Athletics ) were based in

2975-636: The collapse of the Cypress Street Viaduct on the Nimitz Freeway ( Interstate 880 ), where the upper level of a double-deck portion of the freeway collapsed, crushing the cars on the lower level, and causing crashes on the upper level. One 50-foot (15 m) section of the San Francisco–Oakland Bay Bridge also collapsed, leading to a single fatality, Anamafi Moala, a 23-year-old woman. Three people were killed in

3060-434: The damage. That same day, survivor Buck Helm was freed from the wreckage, having spent 90 hours trapped in his car. Dubbed "Lucky Buck" by the local radio, Helm lived for another 29 days on life support , but then died of respiratory failure at the age of 58. Although the freeway reopened in stages between 1997 and 1999, it was not fully rebuilt until 2001 so that it would comply with safety and reinforcement standards. In

3145-468: The death toll at 300, a number that was corrected to 63 in the days after the earthquake. After the earthquake occurred, a group led by Antony C. Fraser-Smith of Stanford University reported that the event was preceded by disturbances in background magnetic field noise as measured by a sensor placed in Corralitos , about 4.5 miles (7 km) from the epicenter. From October 5, they reported that

3230-444: The debris, found one victim alive and another dead inside the coffee house. Santa Cruz beach lifeguards assisted in moving the victims. Police dogs were brought in to help locate other victims. A woman was found dead inside Ford's. The civilians who were helpful initially, were soon viewed by police and fire officials as a hindrance to operations, with frantic coworkers and friends of a coffee house employee thought to be trapped under

3315-416: The development of a kink in one of the plate boundaries. The "Pacific Triangle", the oldest part of the Pacific plate, created during the initial stages of plate formation, is located just east of the Mariana Trench . The growth of the Pacific plate reduced the Farallon plate to a few remnants along the west coast of the Americas (such as the Juan de Fuca plate ) and the Phoenix plate to a small remnant near

3400-415: The distinction of showing one of the largest areal sections of the oldest members of seabed geology being entrenched into eastern Asian oceanic trenches . A geologic map of the Pacific Ocean seabed shows not only the geologic sequences, and associated Ring of Fire zones on the ocean's perimeters, but the various ages of the seafloor in a stairstep fashion, youngest to oldest, the oldest being consumed into

3485-490: The earthquake struck at approximately 5:04 PDT, sportscaster Tim McCarver was narrating taped highlights of Game 2, which had been played two days prior across the Bay Bridge in Oakland. Television viewers saw the video signal begin to break up, heard McCarver repeat a sentence as the shaking distracted him, and heard McCarver's colleague Al Michaels exclaim, "I'll tell you what, we're having an earth – ." At that moment,

Lake Elsman - Misplaced Pages Continue

3570-629: The earthquake. In Santa Cruz , close to the epicenter, 40 buildings collapsed, killing six people. At the Santa Cruz Beach Boardwalk, the Plunge Building was significantly damaged. Liquefaction also caused damage in the Watsonville area. For example, sand volcanoes formed in a field near Pajaro as well as in a strawberry field. The Ford's department store in Watsonville experienced significant damage, including

3655-681: The edge of the freeway. Nearby residents and factory workers came to the rescue, climbing onto the wreckage with ladders and forklifts and pulling trapped people out of their cars from under a four-foot gap in some sections. 60 members of Oakland's Public Works Agency left the nearby city yard and joined rescue efforts. Employees from Pacific Pipe drove heavy lift equipment to the scene and started using it to raise sections of fallen freeway enough to allow further rescue. Local workers continued their volunteer operation nonstop until October 21, 1989, when they were forced to pause as U.S. President George H. W. Bush and California Governor George Deukmejian viewed

3740-399: The epicenter resulted from liquefaction of soil used to create waterfront land. Other effects included sand volcanoes , landslides and ground ruptures. Some 12,000 homes and 2,600 businesses were damaged. The Federal Emergency Management Agency (FEMA) turned people who were homeless prior to the earthquake away from homeless shelters and provided shelter for those with homes prior to

3825-400: The four deaths, one family lost their infant son who choked on dust while trapped for an hour inside their collapsed apartment. The Marina district was built on a landfill made of a mixture of sand, dirt, rubble, waste, and other materials containing a high percentage of groundwater . Some of the fill was rubble dumped into San Francisco Bay after the 1906 San Francisco earthquake, but most

3910-438: 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 . The San Francisco Fire Department selected civilians to help run fire hoses from a distance because the nearby hydrant system failed. Since the bay was only two blocks from the burning buildings, water from the bay was pumped by the fireboat Phoenix , to engines on

3995-512: 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. The June 27, 1988, shock occurred with a maximum intensity of VI ( Strong ). Its effects included broken windows in Los Gatos, and other light damage in Holy City , where increased flow was observed at a water well . Farther away from

4080-507: The late 1950s and opened to traffic in 1957 (as SR 17), the Cypress Street Viaduct, a stretch of Interstate 880, was a double-deck freeway section made of nonductile reinforced concrete that was constructed above and astride Cypress Street in Oakland. Roughly half of the land the Cypress Viaduct was built on was filled marshland and the other half somewhat more stable alluvium . Because of new highway structure design guidelines –

4165-415: The local ABC station in San Francisco, was off the air for about 15 minutes, while KRON-TV (at the time the region's NBC affiliate) was off the air for about half an hour, and KGO-AM ( ABC News Radio ) was off the air for about 40 minutes. 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

4250-413: The mainland and cracked the paved road on Paul's Island. In the Old Town historical district of the city of Salinas, unreinforced masonry buildings were partially destroyed. Following the quake, an estimated 1.4 million people experienced power losses that were mainly due to damaged electrical substations . Many San Francisco radio and television stations were temporarily knocked off the air. KGO-TV ,

4335-547: The meantime, traffic was detoured through nearby Interstate 980 , causing increased congestion. Instead of rebuilding Interstate 880 over the same ground, Caltrans rerouted the freeway farther west around the outskirts of West Oakland to provide better access to the Port of Oakland and the San Francisco–Oakland Bay Bridge, and to meet community desires to keep the freeway from cutting through residential areas (at

SECTION 50

#1732775634669

4420-449: The most expensive natural disasters in U.S. history at the time. Private donations poured into aid relief efforts and on October 26, President George H. W. Bush signed a $ 1.1 billion ($ 2.7 billion today) earthquake relief package for California. Four people died in San Francisco's Marina District, four buildings were destroyed by fire, and seven buildings collapsed. Another 63 damaged structures were judged too dangerous to live in. Among

4505-480: The most frequently cited claims of a specific earthquake precursor; more recent studies have cast doubt on the connection, attributing the Corralitos signals to either unrelated magnetic disturbance or, even more simply, to sensor-system malfunction. The earthquake caused severe damage in some very specific locations in the Bay Area, most notably on unstable soil in San Francisco and Oakland . Oakland City Hall

4590-400: The next morning. Large cracks in Oakland's runway and taxiway reduced the usable length to two-thirds normal, and damage to the dike required quick remediation to avoid flooding the runway with water from the bay. Oakland Airport repair costs were assessed at $ 30 million (equivalent to $ 77 million today). San Francisco Municipal Railway (Muni) lost all power to electric transit systems when

4675-491: The next several hours, some of it picked up and broadcast nationally over their respective networks, as well as on CNN , in a manner anticipating later major catastrophes such as the 1994 Los Angeles earthquake and the 9/11 terror attacks ). Power was restored to most of San Francisco by midnight, and all but 12,000 customers had their power restored within two days. The quake caused an estimated $ 6 billion (equivalent to $ 15 billion today) in property damage, becoming one of

4760-675: The north into the San Francisco Bay Area , both on the San Francisco Peninsula and across the bay in Oakland . No surface faulting occurred, though many other ground failures and landslides were present, especially in the Summit area of the Santa Cruz Mountains. Liquefaction was also a significant issue, especially in the heavily damaged Marina District of San Francisco , but its effects were also seen in

4845-486: The north, portions of San Francisco were assessed at intensity IX ( Violent ). At more than 44 miles (70 km) distant, the San Francisco Bay Area recorded peak horizontal accelerations that were as high as 0.26 g , and close to the epicenter they peaked at more than 0.6 g . In a general way, the location of aftershocks of the event delineated the extent of the faulting, which (according to seismologist Bruce Bolt ) extended about 24 miles (40 km) in length. Because

4930-471: The occurrence of an event at the location that was forecast by the WGCEP in 1988 was coincidental. The contrasting characteristics of the 1906 and 1989 events were examined by seismologists Hiroo Kanamori and Kenji Satake . The significant amount of vertical displacement in 1989 was a key aspect to consider because a long-term sequence of 1989-type events (with an 80–100-year recurrence interval) normally result in regions with high topographic relief , which

5015-415: The office of the Los Gatos City Manager, a window that was cracked had also been broken in the earlier shock. Also in Los Gatos, one man died when he fell or jumped through a window and impacted the ground five stories below. The Loma Prieta earthquake was named for Loma Prieta Peak in the Santa Cruz Mountains, which lies just to the east of the mainshock epicenter. The duration of the heaviest shaking in

5100-402: The open gap in time; the 1980 Mercury Zephyr plunged over the edge and smashed onto the collapsed roadbed. The driver, Anamafi Moala, died, and the passenger, her brother, was seriously injured. Caltrans removed and replaced the collapsed section, and re-opened the bridge on November 18. To assist with transportation during Bay Bridge repairs, Bay Area Rapid Transit ran 24-hour service in

5185-429: The opportunity to assign a new name to the San Juan Bautista segment – the Loma Prieta segment. In early 1988, the Working Group for California Earthquake Probabilities (WGCEP) made several statements regarding their forecasts for the 225 mi (360 km) northern San Andreas Fault segment, the 56 mi (90 km) San Francisco Peninsula segment, and a 18.8–22 mi (30–35 km) portion of that segment which

SECTION 60

#1732775634669

5270-501: The quake hit, but otherwise suffered little damage and no injuries to operators or riders. Cable cars and electric trains and buses were stalled in place – half of Muni's transport capability was lost for 12 hours. Muni relied on diesel buses to continue abbreviated service until electric power was restored later that night, and electric units could be inspected and readied for service on the morning of October 18. After 78 hours, 96 percent of Muni services were back in operation, including

5355-498: The region's freeway system had to be demolished. Damage to the region's transportation system was estimated at $ 1.8 billion (equivalent to $ 4.4 billion today). The 1989 World Series featured the Oakland Athletics and the San Francisco Giants in the first cross-town World Series since 1956 . Game 3 of the series was scheduled to begin at San Francisco's Candlestick Park on October 17 at 5:35 PDT, and American television network ABC began its pre-game show at 5:00 PDT . When

5440-466: The requirement of ductile construction elements – instituted following the 1971 San Fernando earthquake , a limited degree of earthquake reinforcement was retrofitted to the Cypress Viaduct in 1977. The added elements were longitudinal restraints at transverse expansion joints in the box girder spans, but no studies were made of possible failure modes specific to the Cypress Viaduct. Caltrans has since received widespread backlash for not thoroughly studying

5525-438: The rubble continuing their efforts in the dark. Police arrested those who refused to stop searching. This became a political issue in the following days. The body of a young woman coffee worker was found under a collapsed wall late the next day. During the first few days following the quake, electric power to most Santa Cruz County subscribers was out, and some areas had no water. Limited phone service remained online, providing

5610-414: The rupture took place bilaterally, the duration of strong shaking was about half of what it would have been had it ruptured in one direction only. The duration of a typical M6.9 shock with a comparable rupture length would have been about twice as long. Gregory Beroza , a seismologist with Stanford University , made several distinctions regarding the 1906 and 1989 events. Near Loma Prieta, the 1906 rupture

5695-437: The shock was responsible for 63 deaths and 3,757 injuries. 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. Damage was heavy in Santa Cruz County and less so to the south in Monterey County , but effects extended well to

5780-424: 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

5865-473: The shore, and from there sprayed on the fire. The apartment structures that collapsed were older buildings that included ground-floor garages, which engineers refer to as a soft story building . In Santa Cruz, the Pacific Garden Mall was severely damaged, with falling debris killing three people, half of the six earthquake deaths in Santa Cruz and Monterey Counties. Some 31 buildings were damaged enough to warrant demolition, seven of which had been listed in

5950-447: The shores of San Francisco Bay and to the south near Monterey Bay. Other ground effects included downslope movement, slumps , and ground cracks. Fifty-seven of the deaths were directly caused by the earthquake; six further fatalities were ruled to have been caused indirectly. In addition, there were 3,757 injuries as a result of the earthquake, 400 of which were serious. The highest number of deaths, 42, occurred in Oakland because of

6035-533: The signal from Candlestick Park was lost. The network put up a green ABC Sports "World Series" technical difficulties telop graphic while it scrambled to repair the video feed (the broadcast cameras and mics were powered by the local power supply), but audio from the stadium was restored after thirteen seconds via a telephone link: Al Michaels: Well, heh, I don't know if we're on the air... We are in commercial, I guess. Jim Palmer : Yes, yes, we hear you. Tim McCarver: I guess... Michaels: I don't hear

6120-620: 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

6205-409: 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. KCBS later won a Peabody Award for their news coverage, as did KGO-TV. KNBR-AM (the designated station for the Bay Area's Emergency Broadcast System at the time) failed to communicate a catastrophe with the activation and instructions of

6290-602: The steep terrain near the epicenter was prone to movement, and up to 4,000 landslides may have occurred during the event. The majority of landslides occurred to the southwest of the epicenter, especially along road cuts in the Santa Cruz Mountains and in the Summit Road area, but also along the bluffs of the Pacific Coast, and as far north as the Marin Peninsula. Highway 17 was blocked for several weeks by

6375-432: The structure. When the earthquake hit, the shaking was amplified on the former marshland, and soil liquefaction occurred. When the earthquake struck, the freeway buckled and twisted before the support columns failed and the upper deck fell on the lower deck. Forty-two people were crushed to death in their cars. Cars on the upper deck were tossed around violently, some of them flipped sideways, and some were left dangling at

6460-455: The three largest shocks to occur along the 1906 earthquake's rupture zone since 1914. The M L 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

6545-535: The time the original viaduct was constructed, West Oakland was predominantly occupied by African- and Hispanic-Americans). Street-level Mandela Parkway now occupies the previous roadbed of the Cypress structure. Immediately after the earthquake, Bay Area airports were closed so officials could conduct a visual inspection and damage assessment procedures. San Jose International Airport , Oakland International Airport and San Francisco International Airport all opened

6630-404: The way they had come. Eastbound drivers stuck on the lower deck between the collapse and Yerba Buena Island were routed up to the upper deck and westward back to San Francisco. A miscommunication made by emergency workers at Yerba Buena Island routed some drivers the wrong way; they were directed to the upper deck where they drove eastward toward the collapse site. One of these drivers did not see

6715-537: Was damaged in the Loma Prieta quake. The performance of Austrian Dam during that earthquake reinforces concerns about damage to the tops of earth dams by earthquakes. This Santa Clara County, California -related article is a stub . You can help Misplaced Pages by expanding it . 1989 Loma Prieta earthquake On October 17, 1989, at 5:04 p.m. local time, the Loma Prieta earthquake occurred at

6800-473: Was evacuated after the earthquake until a US$ 80 million (equivalent to US$ 197 million today) seismic retrofit and hazard abatement work was completed in 1995. Many other communities sustained severe damage throughout the region located in Alameda , San Mateo , Santa Clara , San Benito , Santa Cruz and Monterey counties. Major property damage in San Francisco's Marina District 60 mi (97 km) from

6885-404: Was more shallow, had more strike-slip, and occurred on a fault that was near vertical. The 1989 event's oblique-slip rupture was at 10 km and below on a fault plane that dipped 70° to the southwest. Because much of the slip in 1989 occurred at depth and the rupture propagated up dip, Beroza proposed that the overlying San Andreas Fault actually inhibited further rupture and also maintains that

6970-719: Was referred to as the southern Santa Cruz Mountains segment. The thirty year probability for one or more M7 earthquakes in the study area was given as 50%, but because of a lack of information and low confidence, a 30% probability was assigned to the Southern Santa Cruz Mountains segment. Two moderate shocks, referred to as the Lake Elsman earthquakes by the USGS, occurred in the Santa Cruz Mountains region in June 1988 and again in August 1989. Following each event,

7055-429: 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 because of when and where they occurred relative to the main event. Each event's aftershock sequence and effect on stress drop was closely examined, and their study indicated that

7140-471: Was sand and debris laid down in preparation for the 1915 Panama-Pacific International Exposition , a celebration of San Francisco's ability to rebound after its catastrophe in 1906. After the Exposition, apartment buildings were erected on the landfill. In the 1989 earthquake, the water-saturated unconsolidated mud, sand, and rubble suffered liquefaction , and the earthquake's vertical shock waves rippled

7225-456: Was severely shaken during the quake, when most of the KNBR staff were at Candlestick for the World Series. The Mayor of San Francisco, Art Agnos , later came on the air and provided an update on the earthquake. (All four network-affiliated TV stations (KRON, KGO, KTVU and CBS affiliate KPIX ) would recover enough to broadcast continuous breaking news coverage of the aftermath of the quake for

#668331