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The Loma Prieta Earthquake of 1989 and Its impact

The Loma Prieta Earthquake of 1989 and Its impact

October 17, 1989, at precisely 5:04:5 (PDT) stands as a memorable moment to California residents. This very moment saw the occurrence of the very powerful earthquake which led to many experiencing quite severe losses. With the epicentre of the Earthquake being in the Santa Cruz Mountains, the earthquake with a magnitude of 6.9 managed to bring quite a number of activities around the region at a standstill.



The cause of the Loma Prieta Earthquake

As with other such natural occurrences, earth movements along some specific geographic region were the cause of the earthquake. The San Andreas Fault system was the major target for the geologists seeking to establish the exact cause. Coming between the Pacific Plate and the North American Plate, the fault is quite significant for those undertaking geological studies relating to earthquakes and earth movements. Prior to Loma Prieta, there was the San Francisco Earthquake that had occurred in the 1906. the San Francisco earthquake was attributed to a 470 kilometre rapture along the San Andreas Fault that lead to shock in the form of massive earth tremors being distributed in the north and south of the Santa Cruz Mountains, which again were the Epicentre. The Loma Prieta terminated the long period of peace following the movements on an oblique-slip reverse fault which geologists established was lying adjacent to the San Andreas Fault.



What happened during the Loma Prieta Earthquake?

The Santa Cruz Mountains were the actual epicentre of the earthquake. Following this establishment, geologists coined the name Loma Prieta, which is essentially a name picked from the Loma Prieta Peak of the Santa Cruz Mountains. For close to quarter a minute, very heavy shaking was experienced in the Santa Cruz Mountains. Apparently, geologists were able to make out the difference in the intensity of the earthquake as a result of the varying soil profile around the mountain. The Cypress Street Viaduct, which lie in a less rocky terrain, were for instance more affected due to the tremors being more severe and longer. Again, it was established that the San Andreas Fault had something to do with the occurrence of the Loma Prieta earthquake.

Peak horizontal accelerations, which were as high as 0.26g, were recorded at the San Francisco Bay. At the Santa Cruz Mountains, the peak horizontal accelerations were at 0.6g. The seismologists' and geologists' investigations lead to the knowledge that ruptures in the San Andreas Fault leading to the Loma Prieta occurred bilaterally, a thing that actually reduced the intensity of the movement. With a unilaterally occurring rupture the earthquakes usually get to be felt at double intensity.



What damages resulted from the earthquake?

Deaths and Injuries

Soon as the earth movements subsided, it was established that 50 lives had been lost in the instance. More than 3700 people incurred injuries in the instance, a number from which six extra lives were lost and from which some sustained long lasting scars and injuries. By the time the air was being cleared out, 63 lives were reported to have been lost. The Cypress Street Viaduct which is least rocky was worst hit. With about 40 lives being compromised in the instance, the area basically came up as one that was hardest hit. The 115 metre San Francisco-Oakland Bay Bridge went tumbling down, with just a single life being lost. Other areas where the Loma Prieta earthquake hit quite hard was the Pacific Garden Mall and the Bluxome Street.


Damages on buildings, businesses and other structures

On the day that Loma Prieta occurred, more than 2500 business men had to seek other sources of income as a result of their business locations being hit by the earthquake. On the same day, more than 11000 homes were damaged thus resulting in such a large number of the residents living around the Santa Cruz Mountains being rendered homeless.

Right at the epicentre of the earthquake, forty buildings were damaged. Major bridges and roads connecting the areas in California were also not left out. An example is the bridge that linked the mainland and Moss Landing. The pair of bridges located near Watsonville had their structures compromised hence required rectification in order for travellers to resume using them without qualms.

A power blackout was experienced upon the occurrence of the Loma Prieta, with more than 1.3 million people reporting to having been affected by the lack of power. Most people has their power restored by midnight though some people still complained of lack of power 48 hours after the occurrence of the earthquake. The loss of power also meant that broadcast services were inaccessible for a period of time. Radio and television broadcasts were inaccessible during this period, though some stations, such as KGO-TV and KCBS were still covering the occurrence of the earthquake.

The financial impact of the earthquake was barely anticipated. With such strength, the Loma Prieta was able to damage quite a substantial amount of wealth in this region. The damage was estimated at a cool $6 billion. This figure stands the largest amongst the figures associated with such damage. With most people having nowhere to turn to following the damage of their living apartments and residential areas, the United States government had to act promptly. $1.1 billion was released from the national treasury following the ascent of the then standing US president, George Bush.