Thursday, May 8, 2008
Day Three, May 7, 2008
Students Amy Martin and Laura Akelyte from the Model Secondary School for the Deaf contributed to today’s blog.
Portuguese Bend Landslide
The day started out cloudy, a little sunny, and cool. On our bus ride we passed oil pumps right in the middle of an urban area. We learned that years of pumping oil from the ground had removed so much oil that many square miles of land surface has dropped down. We talked about this more later in the day at the La Brea Tar Pits.
At our first stop Suzanna Sullivan, a student at University of Massachusetts, and Dr. Michele Cooke talked about landslides and several ways the county government is trying to prevent them. We realized we were all standing on a huge landslide, called the Portuguese Bend, which is famous among geologists all over the world. Houses have been destroyed because the land here has moved over 100 feet! People want to save the houses so they have tried different ways to stop the land from sliding. We saw drainage channels along the road to channel rain water so it does not go into the ground, but is sent to the ocean. The water and sewer pipes in the area need constant fixing. You can see in the picture how the pipes are on top of the ground. The ground movement from the gigantic Portuguese Bend landslide causes the pipes break if they are burried. They talked about people own expensive houses on landslide areas that they cannot sell because buyers know the location is dangerous. Another contributing factor to the landslides is how the ocean erodes sand from the shore at the 'toe', or bottom of the landslide, and so the land above, unsupported, then can slide on down the slope . One prevention for this is to place big rocks to prevent shore erosion. One other prevention measure failed when they inserted long metal/concrete vertical shafts into the hillsides to stabilize them, but these broke 5 months after they were installed.
Griffith Park Observatory
On the way to Griffith Park Observatory we stopped at the University of Southern California to pick up a guest geologist, Dr. James Dolan. He asked us to think about three different way hills can be made in this area — man-made, a fault scarp, or mound of earth caused by an old river passage (an alluvial terrace). Dr. Dolan asked the students to think about these types of hills on the journey to the Observatory. We noticed some buildings have been retrofitted to make them stay strong so they will not fall down during earthquake. Dr. Dolan said if there is one thing about earthquakes to remember is that 'earthquakes do not kill people; buildings do'.
The Observatory is located high on a hill overlooking Los Angeles. The view of the surrounding hills includes the famous Hollywood sign and everyone took many pictures with the sign in the background.
On a windy terrace overlooking the city, Dr. Dolan gave a talk about the faults in the Los Angeles basin and told us there is a huge 'blind' fault under the whole area of Los Angeles which we could see in the valley in front of us. A blind fault is one that is completely underground and there is no evidence of it on the surface. He talked about the 1906 earthquake in San Francisco, the pipes broke and there was no water to put out the fire that followed the quake. Dr. Dolan said the blind fault, called the Puente Hills Fault, moves very slowly (1.6 mm per year) and probably only causes an earthquake only every thousand years or so, but it would be a very dangerous quake if it happens now under the city of Los Angeles. The geologists challenged the students with a contest quiz question: which fault prosed the greatest risk: the San Andreas Fault or the Puente Hills Fault? Dr. Cooke said there was no right answer, but the team that showed the best reasoning would win. Most students gave good answers, but Benjamin Poistra and Quwana Johnson from KSD gave answers that were judged the best and they won Faults in the Field baseball caps.
Hollywood Boulevard Stars and Faults
On our route to the La Brea Tar Pits, we drove through the old section of Hollywood and walked down the boulevard where stars are embedded in the sidewalk with names of famous actors, actresses, and film makers. There is one star for the Apollo 11 astronauts. We stopped at the corner of Hollywood and Vine, the center of old Hollywood. Dr. Dolan showed us how Vine street slopes up a small hill one block to the north. We learned that the hill is actually a large fault, the Hollywood fault, running parralel all along Hollywood Boulevard! We could see the hill when looked up almost every side street from Hollywood Blvd.
La Brea Tar Pits
We stopped for a picnic lunch at the La Brea Pits, taking in the smell of the pits that have tar bubbling up to the surface in black sticky ponds that smell like a hot summer roadway. The Page Museum at La Brea shows how the land was explored for oil and they dug into the tar pits and found millions of fossil bones of mammals and birds from long ago trapped in the tar pits and unable to get out. The bones were found in many layers in the tar pits.
In the museum we saw some scientists working behind a glass window in a lab cleaning bones that had been found on the site. Another scientist was readying the bones to be assembled together. We also saw large existing tar pits in the ground and brand new outbreaks of tar from the size of a dinner plate to several feet across. Dr. Dolan explained that the tar really is oil that has been exposed to the air (oxygen) and becomes sticky. Underground oil finds its way to the surface because of cracks and spaces in the ground. Once on the surface it becomes thick and sticky, and is called tar. The Los Angeles area has many folds underground where oil is trapped, and then we remembered seeing the big oil pumps this morning. The oil companies have mapped out the area very carefully as they look for more oil, and their maps give geologists good information about what's underground.
After the visit to the Tar Pits, we went out to dinner and could pick either a local Mexican restaurant or place called Fat Hamburger! Everyone enjoyed a meal out. We returned to our hotel in Long Beach to work on our presentations for Friday.
Portuguese Bend Landslide
The day started out cloudy, a little sunny, and cool. On our bus ride we passed oil pumps right in the middle of an urban area. We learned that years of pumping oil from the ground had removed so much oil that many square miles of land surface has dropped down. We talked about this more later in the day at the La Brea Tar Pits.
At our first stop Suzanna Sullivan, a student at University of Massachusetts, and Dr. Michele Cooke talked about landslides and several ways the county government is trying to prevent them. We realized we were all standing on a huge landslide, called the Portuguese Bend, which is famous among geologists all over the world. Houses have been destroyed because the land here has moved over 100 feet! People want to save the houses so they have tried different ways to stop the land from sliding. We saw drainage channels along the road to channel rain water so it does not go into the ground, but is sent to the ocean. The water and sewer pipes in the area need constant fixing. You can see in the picture how the pipes are on top of the ground. The ground movement from the gigantic Portuguese Bend landslide causes the pipes break if they are burried. They talked about people own expensive houses on landslide areas that they cannot sell because buyers know the location is dangerous. Another contributing factor to the landslides is how the ocean erodes sand from the shore at the 'toe', or bottom of the landslide, and so the land above, unsupported, then can slide on down the slope . One prevention for this is to place big rocks to prevent shore erosion. One other prevention measure failed when they inserted long metal/concrete vertical shafts into the hillsides to stabilize them, but these broke 5 months after they were installed.
Griffith Park Observatory
On the way to Griffith Park Observatory we stopped at the University of Southern California to pick up a guest geologist, Dr. James Dolan. He asked us to think about three different way hills can be made in this area — man-made, a fault scarp, or mound of earth caused by an old river passage (an alluvial terrace). Dr. Dolan asked the students to think about these types of hills on the journey to the Observatory. We noticed some buildings have been retrofitted to make them stay strong so they will not fall down during earthquake. Dr. Dolan said if there is one thing about earthquakes to remember is that 'earthquakes do not kill people; buildings do'.
The Observatory is located high on a hill overlooking Los Angeles. The view of the surrounding hills includes the famous Hollywood sign and everyone took many pictures with the sign in the background.
On a windy terrace overlooking the city, Dr. Dolan gave a talk about the faults in the Los Angeles basin and told us there is a huge 'blind' fault under the whole area of Los Angeles which we could see in the valley in front of us. A blind fault is one that is completely underground and there is no evidence of it on the surface. He talked about the 1906 earthquake in San Francisco, the pipes broke and there was no water to put out the fire that followed the quake. Dr. Dolan said the blind fault, called the Puente Hills Fault, moves very slowly (1.6 mm per year) and probably only causes an earthquake only every thousand years or so, but it would be a very dangerous quake if it happens now under the city of Los Angeles. The geologists challenged the students with a contest quiz question: which fault prosed the greatest risk: the San Andreas Fault or the Puente Hills Fault? Dr. Cooke said there was no right answer, but the team that showed the best reasoning would win. Most students gave good answers, but Benjamin Poistra and Quwana Johnson from KSD gave answers that were judged the best and they won Faults in the Field baseball caps.
Hollywood Boulevard Stars and Faults
On our route to the La Brea Tar Pits, we drove through the old section of Hollywood and walked down the boulevard where stars are embedded in the sidewalk with names of famous actors, actresses, and film makers. There is one star for the Apollo 11 astronauts. We stopped at the corner of Hollywood and Vine, the center of old Hollywood. Dr. Dolan showed us how Vine street slopes up a small hill one block to the north. We learned that the hill is actually a large fault, the Hollywood fault, running parralel all along Hollywood Boulevard! We could see the hill when looked up almost every side street from Hollywood Blvd.
La Brea Tar Pits
We stopped for a picnic lunch at the La Brea Pits, taking in the smell of the pits that have tar bubbling up to the surface in black sticky ponds that smell like a hot summer roadway. The Page Museum at La Brea shows how the land was explored for oil and they dug into the tar pits and found millions of fossil bones of mammals and birds from long ago trapped in the tar pits and unable to get out. The bones were found in many layers in the tar pits.
In the museum we saw some scientists working behind a glass window in a lab cleaning bones that had been found on the site. Another scientist was readying the bones to be assembled together. We also saw large existing tar pits in the ground and brand new outbreaks of tar from the size of a dinner plate to several feet across. Dr. Dolan explained that the tar really is oil that has been exposed to the air (oxygen) and becomes sticky. Underground oil finds its way to the surface because of cracks and spaces in the ground. Once on the surface it becomes thick and sticky, and is called tar. The Los Angeles area has many folds underground where oil is trapped, and then we remembered seeing the big oil pumps this morning. The oil companies have mapped out the area very carefully as they look for more oil, and their maps give geologists good information about what's underground.
After the visit to the Tar Pits, we went out to dinner and could pick either a local Mexican restaurant or place called Fat Hamburger! Everyone enjoyed a meal out. We returned to our hotel in Long Beach to work on our presentations for Friday.
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