San Joaquin Valley Case Study

The San Andreas fault line has caused constant development nightmares for large urban areas such as San Francisco as well as the other cities built on top of it. Fault lines are one of the side effects of the earth’s tectonic plates shifting that can result in devastating earthquakes. Some of the most devastating earthquakes in our modern era have occurred along the San Andreas fault line due to a dense population. The most notable and destructive earthquake on the San Andreas fault line occurred in San Francisco in 1906. The reason this earthquake was so deadly was because of its magnitude and the city’s poor planning. This earthquake was a wakeup call for San Francisco and force the city to revolutionize its knowledge on earthquakes and how to protect their city. Today San Francisco is one of the most well prepared cities for an earthquake and has made great discoveries in earthquake safety measures. The 1906 earthquake in San Francisco has drastically changed how the city has developed its zoning and building code policies, and its earthquake research.

The gravitational stress on the volcano flanks develops large-scale on-shore and off-shore sliding, related to the activity of the rift zones. The M=7.2 earthquake at Kilauea on 1975 was probably related to strain accumulated throughout the south flank from dikes intruded in the rift zone (Swanson et al., 1976). However, the earthquake itself resulted from abrupt southward movement of the south flank across the underlying oceanic crust, activating the Hilina-Pali fault system. Such faulting not only provides a means for the flanks to adjust continuously to intrusions, but also generates the stress patterns needed to constrain future dikes to propagate along the rift axis. Therefore, rift intrusion and lateral spreading are major contributors

The oldest rocks found in the Death Valley region were formed in the Precambrian time period no more than 1.8 billion years ago during the latter half of the Proterozoic Eon. The rocks are seen on the steep face of the Black Mountains above the current area of Badwater and were formed via deposits of mud and sand from an ancient volcanic mountain belt. Sometime between 1.8 and 1.7 billion years ago, the volcanic and sedimentary rocks were severely altered when chemical or structural changes occurred because of intense heat or pressure from the Earth's core. Because of this process, any fossilized information about the region was lost making it impossible to truly understand the origin of the region. There is some debate on whether basalt or schist was the original and dominate rock in the region before it was transformed into contorted gneiss, but again, there is no way to prove either theory.

California’s unique geography as a state makes it a very appealing place to call home. From the odd east to west transverse San Gabriel mountain ranges of the Los Angeles Basin, to the bumpy coastal ranges of the Bay Area, any person can find a compatible topographic terrain to their liking. California may seem to be the perfect place to live with its ideal climate and extensive geographic features. However, due to California’s location over the shifting continental plates, coupled with its enormous and also multiple faults, at any time this great state can fall victim to a seismic disaster. After examining evidence from both Rong-Gong Lin’s II Los Angeles Times article of April 18, 2016 and the NOVA videos Killer Quake ( 2006), Earthquake (2007), as well as Geologic Journey II – Episode 3 (The Pacific Rim: Americas) – Part 3 (San Francisco) and The Great San Francisco Earthquake (American Experience ~ 2005), one can take a comparative account of the three major earthquakes of California’s past. Although each earthquake was very devastating on is own; the Great Quake 0f 1906, the Loma Prieta quake of 1989, and the NorthRidge quake of 1994 each amounted to an extensive forfeiture of property and life. Each of these earthquakes created much suffering and loss. It is imperative for each citizen of this great state to understand the damage that a California quake can actually do and be prepared; for the threat of one always looms.

According to Townend and Zoback (2004) the San Andreas Fault (SAF) region has been noted for its possession of stress orientations in addition to the lack of a distinct heat flow anomaly at the trace of the fault. These findings indicate that there are average shear tractions that are less than 20-25 MPa in the seismogenic upper crust. Oftentimes, shear tractions measure approximately 5 times greater than in the SAF. Due to the presence of high

On August 24, 2014 a magnitude 6.0 earthquake occurred in and around the city of Napa, CA. The earthquake killed one person and injured over 150 people. And these people were treated at Queen of the Valley Medical Center in Napa [1]. More and more earthquakes occurred on this earth. So this grasps people’s attention.

• This earthquake may not have released all of the strain stored in its rocks next to the fault this reveals a potential earthquake in the Santa Cruz Mountains in the near future. The occurrence of the earthquake showed that the Earth did not exhaust all its strain and hence other earthquakes could be expected. However, the dates could not be predicted. The extent of the damage could have been much more devastating for the region, but with the earthquake occurring near the coast this made half of the felt area westward in the Pacific Ocean. The occurrence of aftershocks ten days later reinforces the unpredictability nature and hence makes Geology to be a study that is always evolving. In conclusion, the Earth and the study of cannot be exhausted as every natural occurrence provides a new puzzle to be solved.

The 1906 San Francisco Earthquake tectonic setting was in the outermost shell of earth known as the crust this is composed of rigid plates that have been moving for hundreds of millions of years. Two of these moving plates meet in western California; the boundary between them is a zone of faults, the principal one being the San Andreas fault. The horizontal sliding of the Pacific Plate relative to the North American Plate, causes earthquakes along the San Andreas fault and similar plates near the region. The San Andreas fault is a transform plate boundary, accommodating horizontal relative motions (usgs.gov).

The Mesozoic tectonic history of the North American Cordilleran region is very complex and involves:

First, we must examine the sedimentary formations; when they were formed, how they were formed, and what materials they consist of. About ninety-three to one hundred million years ago, the Western Interior Seaway rolled through the North American continent, eventually reaching the geographical area of today’s Mesa Verde National Park (National Park Service 2005). This sea deposited a thick, hard sandstone base that is called Dakota Sandstone, although this layer is not exposed in the park

Southern California is nestled between the Pacific Plate and the North American Plate. One of the most famous faults talked about in recent times, is the San Andreas fault which runs through Palmdale, San Bernadino, and Palm Springs. And as you can see by Figure 2, The Elsinore fault runs more closely in my direction as it runs through Los Angeles. A more in depth, and upclose search will show you that near the area of Mission Hills, there are three faults. There is the Santa Susana Fault that runs through Granada Hills and Los Angeles, all the way through part of the San Fernando Fault Zone. Mission Hills Fault can be seen further south running through part of Northridge and eventually reaches a connecting point with the San Fernando Fault

The extent to which tectonic processes represent a hazard depends upon when and where they are experienced (40)

The Long Point Fault is located in Harris County, which covers 83,450 square miles located with in Houston, Teaxas City Limits. Research specifies that there are three sections of the Long Point fault that appear to be active; some sections of the Long Point fault have averaged more than 2 cm per year of vertical offset over the last 20 years. Evidence of the faults concludes it is a natural fault. The reason for activity is not caused by man, even though man’s activities are not helping the issues, but clearly humans are not the initial cause, biological activity can be in fact an adiitional cause for its movement. A brief description of the type of fault and its relationship with the strata and the faults

Scientist are struggling to come up with a widely accepted model that will explain the role of non-vertical strike-slip fault segments, crustal movement and deformation within Pacific –North American plate boundary. Multiple methods of analysis are being used; some of which are described below.

The boundary between the Upper Pliocene and the overlying sequence 11880-12596 is placed at the unconformity recognized at the 8050feet. The unconformity is recognized by the presence of pebbles overlain and underlain by shale, which is interpreted ad indicating the termination of a cycle of sedimentation. The sequence between 6130-7090 yielded, at scattered intervals, stratigraphically significant taxa and their age ranges in literature include Impagidinium patulum (Middle Miocene- Pliocene)