Presentation on theme: "Done by: Zhu HuaYing 3A1 (31) Li ShiCheng 3A1 (16) Brian Teo Kian Peng 3A1(26) Han Xuyang 3O1 (003) Yu JiaKe 3O1 (29) Xu ZiHao 3O1 (27) SAN ANDREAS FAULT."— Presentation transcript:
Done by: Zhu HuaYing 3A1 (31) Li ShiCheng 3A1 (16) Brian Teo Kian Peng 3A1(26) Han Xuyang 3O1 (003) Yu JiaKe 3O1 (29) Xu ZiHao 3O1 (27) SAN ANDREAS FAULT
CONTENTS Introduction What is a fault? Where is it located? Motion occurred along the fault The Great San Francisco Earthquake Three segments of the fault. Economical Gains Myth about the San Andreas Fault Fun Facts about the San Andreas Fault Northern segment Central segment The next “Big One” Southern segment
INTRODUCTION The Pacific Plate (on the west) moves northwestward relative to the North American Plate (on the east), causing earthquakes along the fault The entire San Andreas fault system is more than 800 miles(1,300 km) long and extends to depths of at least 10 miles within the Earth The fault is a complex zone of crushed and broken rock from a few hundred feet to a mile wide. Many smaller faults branch from and join the San Andreas fault zone It is about 28 million years old.
WHAT IS A FAULT? A planar crack in a rock along which slippage has taken place. Most faults are small - even microscopic - and are not important. Some faults are a few miles long.
WHERE IS IT LOCATED? Passes through California, a densely populated state, thus major earthquakes can cause much destruction The boundary between the North American and Pacific lithospheric plates The plates move past one another at the speed of around 2.5 inches a year, about as fast as your fingernails grow. Fault line
MOTION OCCURRED ALONG THE FAULT Motion of Blocks on opposite sides of the San Andreas fault is right-lateral strike- slip. (horizontally) Under the influence of the plate movements, all land west of the fault on the Pacific Plate is moving slowly to the northwest All the land at the east of the fault is moving Southwest The rate of slippage averages approximately 33 to 37 millimeters annually across California.
THE GREAT SAN FRANCISCO EARTHQUAKE April 18, 1906 it attracted dramatic world attention Sudden displacement along the fault produced the Great San Francisco earthquake One of the most significant earthquakes.
THE NEXT “BIG ONE” Studies have shown the San Andreas Fault to be stressed to a level sufficient for the next “Big One”, an earthquake which might measure 7.0 or bigger on the Richter scale Believe the earthquake might occur near Southern Section which can cause great damage to a number of cities in California Information collected thus far has proved that the fault is ready for an earthquake, but is unable to determine when the triggering will happen Holes have been drilled deep into the fault to place machinery to track the movements of the San Andreas Fault and to predict when the earthquake will be triggered.
THREE SEGMENTS OF THE FAULT Northern segment The northern segment of the fault runs from Hollister, through the Santa Cruz Mountains, epicenter of the 1989 Loma Prieta earthquake. This is the approximate location of the epicenter of the 1906 San Francisco earthquake and it is about 300 km Central segment The central segment of the San Andreas fault runs in a northwestern direction from Parkfield to Hollister. The Parkfield segment is at the center of the San Andreas fault. Hardly 30 kilometers long, while the southern section of the fault and the parts through Parkfield experience earthquakes the rest of the central section of the fault exhibits a phenomenon called aseismic creep, where the fault slips slowly without causing earthquakes.
THREE SEGMENTS OF THE FAULT Southern segment The southern segment (known as the Mojave segment) begins near the Salton Sea at the northern terminus of the East Pacific Rise. It runs northward before it begins a slow bend to the west where it meets the San Bernardino Mountains. Then it crosses through the Cajon Pass and continues to run northwest along the northern base of the San Gabriel Mountains These mountains are a result of movement along the San Andreas Fault and are commonly called the Transverse Range After crossing through Frazier Park, the fault begins to bend northward. This area is referred to as the "Big Bend" and is thought to be where the fault locks up in Southern California as the plates try to move past each other This section of the fault has an earthquake-recurrence interval of roughly 140–160 years.
ECONOMICAL GAINS Flights and helicopter rides that allow people to view the San Andreas Fault more clearly from a vantage point As the San Andreas Fault moves, it has created mountains valleys and lakes, attracting tourists State parks are also constructed along the fault where people can go camping, bird watching, have picnics, etc.
MYTH ABOUT THE SAN ANDREAS FAULT One of the biggest myth about the San Andreas Fault is that one day, it will buckle, crack and cause California to slide into the sea Some are simply superstitious because of the large number of earthquakes Some people had “visions” of this This is impossible as California is firmly attached to America and the Pacific plate.
FUN FACTS ABOUT THE SAN ANDREAS FAULT Research has shown that the Southern segment, which stretches from Parkfield in Monterey County, California all the way down to the Salton Sea, is now capable of a Richter scale 8.1 earthquake An earthquake of that size on the Southern segment (which, at its closest, is 40 miles away from Los Angeles) would kill thousands of people in Los Angeles, San Bernandino, Riverside, and other areas, and cause hundreds of billions of dollars in property and economic damage The fault was first identified in Northern California by UC Berkeley geology professor Andrew Lawson in 1895 and named by him after a small lake which lies in a linear valley formed by the fault just south of San Francisco, the Laguna de San Andreas ( San Andreas Lake). The 2008 Sichuan earthquake in China
FUN FACTS ABOUT THE SAN ANDREAS FAULT In central California is the small town of Parkfield, which lies along the San Andreas Fault Seismologists discovered that this section of the fault consistently produces magnitude 6.0 earthquakes about every 22 years Following earthquakes in 1857, 1881, 1901, 1922, 1934, and 1966, scientists predicted an earthquake to hit Parkfield in 1993. It eventually struck in 2004, the Parkfield earthquake.
VIDEO CLIPS San Andreas Fault (Discovery Channel) Earthquake Country LA Chapter 3 San Andreas Fault
REFLECTIONS BY ZHU HUAYING This is an interesting topic as I can discover the resultant landform when two plates slide past each other. I personally think that it is more unique than constructive or destructive plate boundaries. The most famous San Andreas Fault gives me the chance to explore and learn by myself. The theories, the facts and fun facts.
REFLECTIONS BY LI SHICHENG I am responsible for the pictures so I learnt a lot about the geologic conditions and how the San Andreas fault looks like. I also had a deeper understanding about the movement of the two plates and how the fault affects the cities around it, positive and negetive.
REFLECTIONS BY BRIAN TEO KIAN PENG From this PowerPoint, I can understand the process behind the formation of faults better and can also better understand the different plate movements of the earth which gave rise to the many different landforms.
REFLECTIONS BY HAN XUYANG I have learn a lot from the production of the PowerPoint. I also have a better understanding of the San Andreas fault, its location, facts, the economical benefits that tourism there can bring about and the myths of the San Andreas fault.
REFLECTIONS BY YU JIAKE After this preparation for presentation, I learnt more about the San Andreas Fault. I also found that there are many ways to get information. Videos and information from internet attracted me so much that I am more interested in this subject now.
REFLECTIONS BY XU ZIHAO Through the process of presenting, I knew a lot of new things that I have never learnt before. For example, I never believed that I could have one foot on the plate of pacific and the other on the North-America, because I used to think that the movement of plates are all quite violent. What's more, during the presentation, I learnt the benefits of teamwork.