A look at earthquakes from the beginning of man's first writings to the present, including how scientists over history have measured, predicted and mapped earthquakes.
1,675 words (approx. 6.7 pages), 10 sources, 2001, $ 54.95
Abstract This paper analyses earthquakes from the beginning of man's first writings on the topic to today's time. The paper starts with Greek philosopher's notes on them and continues all the way to today's scientists, who have broken down earthquakes to seismic waves. The paper also discusses the history of scientists tracking ability of the earthquake, detailing the birth of the Richter scale. The paper goes into great scientific detail about how earthquakes are measured, predicted and mapped.
Abstract Much as the science has progressed, it cannot, to this day, predict earthquakes with accuracy. This ten-page paper discusses earthquakes in general, the origins of its predictions, methods of predictions and any new technologies that might be associated with them. The paper concludes by discussing the impact of earthquakes on the real estate business of Los Angeles and San Francisco.
Abstract An analysis of how both minor and major faults can lead to earthquakes. The paper includes a summary of the background of the Bay Area and explains how not all the earthquakes are found in the regions where the major faults lie and notes there are also unmapped faults. The paper discusses how the area not only demonstrates historical significance with regard to earthquake activity, but it is a region of the nation that has recurring earthquakes on a daily basis, though small in scale.
From the Paper "There are seven major faults in the San Francisco Bay Area. These faults become active through the "strike slip motion" of the Pacific and North American tectonic plates ("Working"). Research contends that, Although most of the present-day seismicity in Bay Area generally follows the major faults (San Andreas, Hayward-Mission Creek, Concord-Calaveras, and Antioch faults), a significant fraction occurs in the large (8 km) right-step-over region between the Calaveras and Concord faults and along the Mt. Lewis seismic zone. In addition, numerous earthquakes locate in the regions between the major faults and seismic zones and appear to lie on either the minor faults or on unmapped faults ("Bay Area"). Although these major faults have historically played a role in the major earthquakes that have affected the San Francisco Bay Area, scientists now conclude that at any time minor faults could create..."
Abstract The paper provides a report for the people of Fairbanks Alaska regarding earthquakes. The paper looks at why Alaska has so many earthquakes and concludes that another is inevitable It also looks at options for minimizing the damage caused by earthquakes.
From the Paper "Earthquakes are usually connected with fault lines. Fault lines are areas in which tectonic plates are moving more frequently then other areas(Hobbs 272). Although techonic plates are moving everywhere they are usually not moving fast enough for anyone to realize. Earthquakes occur when techonic plates achieve a high enough velocity to cause the ground to actually shake."
Abstract This paper presents a review of historical accounts of the 1750 London earthquakes. It looks at issues that must be considered in reading the original reports of the earthquakes and the differences in interpretations in the reports.
From the Paper "Perhaps the most significant distinction that can be made between thes econdary reports of Lecky and Langford and that of Speck is that the former attribute the prediction of the third earthquake to a crazy soldier and a lunatic trooper ..."
Abstract This paper gives a detailed first person account of the earthquake in Santa Clarita, California from the eyes of a public information officer. It describes the policies such as: activating the Emergency Alert System, restoring power and more. It details the responses that were received by disaster relief personnel and how several organizations of emergency workers were able to deal with this crisis.
From the Paper "On Thursday the 15th of last month, at 7:31 a.m., an earthquake of 5.9 Moment Magnitude struck Southern California. The epicenter was near Santa Clarita, a small suburban community about twenty miles north of Los Angeles along the I-5 freeway. I am the Public Information Officer for the Emergency Response Office for the City of Santa Clarita. The following is an account of the five days following that earthquake."
Abstract This paper discusses how Alaskans are used to numerous earthquakes, but the 2002 disaster in Fairbanks' hinterland pointed to the necessity of attending to immediate human results then quickly repairing road infrastructure. The state's insurance industry works collaboratively with state emergency planning towards properties rebuilt according to regulations meant to fortify structures.
From the Paper "Earthquakes in the area of Fairbanks, Alaska represent an important case in terms of how the dangers of earthquakes are evaluated, in responses to their accompanying losses, and also the intended response to future earthquakes. For instance, the March 1964 'Great Alaska Earthquake' had a strong impact on groundwater thousands of miles distant, in more than 700 ground wells in the continental United States to show water-level changes including one of 12-feet in a well in South Dakota; a well in Australia, for that matter, fluctuated by more than 2 feet after the same disaster. "
Abstract This paper examines the causes and predictors of earthquakes in the earth's surface. It discusses various factors and examines which of the factors act as the most reliable predictor of earthquakes. The paper then looks at how to measure earthquake strength and particularly discusses the advantages of the Richter scale and the Mercalli scale.
Table of Contents:
Earthquake Causes and Predictors
The Most Reliable Predictor of Earthquakes Measuring Earthquake Strength
From the Paper "If the concern is strictly over the amount of damage a quake can cause, and that is truly the goal of early prediction of earthquakes, then the Mercalli scale would be more effective. Unfortunately, this data is only available after the fact. A consistent Mercalli reading over time can provide a more effective means of protecting against an earthquake, or against damage to humanity. The magnitude of the quake provided by the Richter scale is more effective in building up over time recordings of the occurrence of major quakes for the sake of data and catastrophic protection."
Abstract Western British Columbia is situated near an active subduction zone. The most densely populated part, the Lower Mainland, is actually sitting on the subduction zone. This paper explains that this dynamic geological setting subjects the region to frequent seismic activity and is, in large part, responsible for a higher risk of destructive earthquakes in comparison to other parts of Canada. While the principal city of Vancouver and its surroundings have not experienced a damaging earthquake so far, large earthquakes with nearby epicenters have been strongly felt, and there is paleoseismic evidence for very large earthquakes in the late Holocene. Hazards associated with earthquakes are discussed in detail, and recommendations are given on how to minimize the impacts of a megathrust earthquake and its accompanying hazards. Paper contains 6 figures and charts.
From the Paper "Western British Columbia is situated at a dynamic geological setting which causes it to be the most seismically active in Canada and makes it one of the few sites around the world capable of producing a megaquake of a magnitude of ~9. While such a quake has not hit the region in settled time, paleoseismic evidence, oral history traditions and Japanese records date such a quake as having occurred in 1700. There is also evidence which point to these megathrust events as happening at irregular intervals which range from 200 to 800 years. Vancouver lies at the north end of a seismically active region which extends down into Washington State and has its end south of the Puget Sound. Areas directly off the coast of Vancouver Island and all along the Juan de Fuca plate and Cascadia Subduction Zone are very seismically active. The impact of an earthquake over 6 in magnitude with an epicenter near the Lower Mainland would be devastating on the region, if it occurs off the coast of Vancouver Island, even greater damages would be incurred by tsunami. While new building codes to increase safety structures are due to be released in 2005, it may be too late, as a large quake could hit the region any time, and we have no way to predict such quakes."
Abstract This paper discusses the Northridge earthquake that hit the San Fernando Valley area of Greater Los Angeles on January 17, 1994. The paper specifically reviews the economic impact of the earthquake, as well as the psychological aftermath for the residents of the area. It also discusses the news coverage of the earthquake and general related information.
Table of Contents:
Introduction
Economic Impact
Northridge Earthquake General Information
Northridge Earthquake News Coverage
Suicides Due to the Northridge Earthquake Psychological Distress Following the Northridge Quake
From the Paper "While the earthquake itself didn't result in an increased rate of suicides, the same publication (Prehospital and Disaster Medicine) with mostly the same authors (Bourque, Shoaf, et al, 2002) shows that there was additional psychological distress on the day of the quake. On an average day in LA County there are an estimated 60-80 deaths associated with "cardiovascular events" (IHD, "ischemic heart disease" - heart attacks - and atherosclerotic cardiovascular disease ACD). Meanwhile, in the 16 days preceding the January 17 Northridge quake deaths associated with IHD and ACD averaged 73 per day; on the day of the quake, 125 IHD / ACD death occurred. But for the rest of the month of January following the 17th, the average dropped to 57 deaths per day attributed to IHD and ACD."
Abstract The paper reveals that one earthquake is felt on our fragile planet every thirty seconds! The paper then describes how earthquakes happen, their costly and destructive results and how they are measured. The paper relates that while earthquakes cannot be predicted, it is possible for us to limit the damage and impact they have, by building structures using earthquake resistant designs and ensuring that the interiors of our buildings are safe from falling objects. The paper concludes that ultimately, what is important is to educate people about earthquake safety.
From the Paper "One earthquake is felt on our fragile planet every thirty seconds. There is a 100% chance that somewhere, today, an earthquake is shaking the ground. We have no way of predicting how and when an earthquake will strike. We can only say that it might. No one can say for sure if the tremors that are felt will be enough to kill and wreak havoc. What we can be sure of is that earthquakes are perhaps the most powerful and destructive forces of nature. We should all know the facts and what if anything we can do to be prepared for such a catastrophe."
Abstract This paper on April 18, 1906, San Francisco, California was hit by one of the most devastating earthquakes recognized by man, affecting 430 kilometers of the famous San Andreas fault ranging from northwest of San Juan Bautista to Cape Mendocino, reducing the city into a pile of rubble. The author points out that casualties from the earthquake were severe, with almost 500 deaths in San Francisco and 166 deaths reported in surrounding areas; people wandered about in a state of devastation, shock, helplessness, and sorrow, and thousands were evacuated by the Navy from the city in what was one of the largest evacuations in history. The paper reports that seismology has led to predictions about earthquakes in other areas in the U.S., including Boston and other regions of the East Coast and middle America.
Table of Contents
Geology of the Earthquake The Human Toll and Economy
Rebuilding a Great City
From the Paper "The total length of the earthquake was felt for about 290 miles, the largest ever recorded. The magnitude of the earthquake was estimated between 7.7 and 7.9. Because seismology and the study of earthquakes were limited during the early 1900s, an accurate assessment of the magnitude is not possible. There are some accounts that suggest that the earthquake was as great as 8.3, but these are largely unproven. Before this earthquake, little scientific effort was dedicated to seismic research. After the earthquake however scientists took an active interest in the area of seismography and government issued investigations into earthquakes became quite commonplace."
Abstract This paper begins with a description of the destruction caused by the 1995 earthquake in Kobe, Japan and then takes a look at why the region suffered such extensive damage. The paper describes how the traditional Japanese home is constructed as well as how commercial buildings and transportation-related structures are typically constructed and explains why these structures could not withstand the force of the earthquake. The paper also points out the need to adopt newer methods of construction in order to make the homes and buildings safer and more capable of withstanding earthquakes.
From the Paper "In 1990, the Japanese Meteorological Agency made a list of 18 regions that experienced seismic activity of less than 3 on the Richter scale. The regions on this list were considered "earthquake-proof". On January 17, 1995, to the surprise of the researchers involved, Kobe, Japan, one of the locations on the safe list, was struck by one of the most severe earthquakes known to mankind at 5:46 a.m. (Japanese Standard Time) (See Figures 1 &2). The magnitude of this earthquake measured 6.9 on the Richter scale and 7.2 on the Japanese Meteorological Agency scale. As a result of this earthquake, 5470 people were killed, 33,000 more were injured and a total of 310,000 local residents were left homeless. Water mains and gas lines were badly damaged. Survivors of the earthquake were left without many of the essentials for everyday life. Eventually, citizens were informed that they could be without water and gas systems for two months or more. Several larger structures including transportation systems, office buildings, and bridges were also damaged during the earthquake (Figure 3). As of April 22, 1995, $110 billion had been spent trying to restore Kobe to livable conditions. "
Abstract Analysis of January 1994 Southern California earthquake. Focal depth of 6.7 magnitude quake. Blind thrust type quake. The fault involved (Oak Ridge system, Pico thrust). Types of damage from the quake (liquefacation, lateral spreading, landslides, differential compaction). Greter damage to Santa Monica. Comparison to 1971 Sylmar earthquake. Retrofitting & engineering codes.
From the Paper "1994 Northridge Earthquake
The 1994 Northridge Earthquake occurred at 4:30:55 AM PST on January 17, 1994. It was measured as a magnitude 6.7 on the Richter scale. This quake occurred along the Northridge Thrust, a fault that is also known as the Pico Thrust. It was centered about 20 miles northwest of Los Angeles and approximately 1 mile south?southwest of Northridge. This quake was a blind thrust type quake.
This particular fault dips to the south at an almost 45 degree angle. As a result, quakes along this fault and similar thrust faults falsely appear far removed from the surface trace. This particular fault forms the ridge slightly to the south of its trace, paralleled by the Santa Clara River and California Sate Highway 126. It begins near the town of Piru in the east and ends just..."
Abstract Analysis of the October 1989 Northern California earthquake. Creation of the 7.1 magnifude quake by a slip in the San Andreas fault line. Depth of the quake. Occurrence of aftershocks and their magnitude. Areas of devastation; why some areas suffered greater damage than others. Landslides. Probability of a repeat high magnitude earthquake.
From the Paper "1989 Loma Prieta Earthquake
The 1989 Loma Prieta Earthquake occurred at 5:04 PM on Tuesday, October 17, 1989. It was measured as a magnitude 7.1 on the Richter scale, a device utilized for measuring earthquake strength. It lasted about 20 seconds and was centered approximately 60 miles south of San Francisco. The tremor could be felt as far south as San Diego and as far east as Western Nevada. This earthquake was pinpointed along the San Andreas Fault line, long considered one of the most dangerous and active portions of the fault.
The famed San Andreas fault line runs along a northwesterly direction about 800 miles from the Gulf of California up to Cape Mendocino just north of San Francisco. This particular fault has been the source of many large quakes, including the 7.0 1838 quake on the..."
