Learn more. RevWood now features WetProtect making it the right kind of waterproof floor. WetProtect technology gives the floor water-tight joints, a waterproof finish that repels water away from the joints and a lifetime surface and subfloor waterproof warranty.
Featuring premium hardwood visuals, maximum scratch protection, and fade resistance in a variety of price points, RevWood offers long lasting beauty your customers will love on any budget. SmartStrand Silk Forever Clean offers silky softness. SmartStrand Silk Forever Clean is the softest, most durable, easiest to clean carpet on the planet.
EverStrand Soft Appeal offers all of the features you love about EverStand — plus enhanced softness and ForeverFresh odor-reducing technology. Wool is naturally non-allergenic, easy to clean, incredibly durable, crush and static resistant and exceptionally soft. Karastan wool provides lasting beauty in sophisticated decors. Wool is a sustainable choice for living beautifully.
No products found. Griffith Park by Phenix. See in my room. Request info. Please update your selection. It is the same general orientation as for the Raymond and Hollywood Faults, which are both active. Stereonet plots of prominent joint pairs, from the area near Beacon Hill in Griffith Park. These are projections of joint planes, and each gridded circle is meant to be the hollowed out bottom half of a sphere.
The top left stereonet in the figure was measured from the joint pair shown in Figure 8. Stereonet diagrams of 86 joints from the Beacon Hill area and also 11 joints from the summit itself are shown in Figure These are plotted as poles, that is, lines perpendicular to the joint planes. They are easier to see on a stereonet, since each pole is represented as a single point slicing through the surface of a sphere rather than as a line.
More poles are in the more darkly shaded regions. If joints are in V-shaped pairs, then the polar directions should average and the relative inclinations cancel to reveal the direction of principal stress. Note that the predominant polar alignment is at approximately N60W, and the direction perpendicular to this is N30E. The direction N60W is the same general bearing as the Verdugo Fault, which is a low angle thrust fault, also currently active.
A secondary stress perpendicular to this fault would be at N30E. It is useful that the jointing follows some of the same bearings as the closest faults here, as a teaching opportunity. The V-shapes are often obvious, and so is, for example, the front of the Verdugo Mountains, beside which the Verdugo Fault runs.
In the top row there is a stereonet plot of 86 joints near the Beacon Hill area of Griffith Park. To the right of this is a contour graph of the associated poles to the joint planes.
A pole is the line perpendicular to the plane, and is easier to plot on a stereonet, since it is represented by a point rather than a line. In the bottom row there is a stereonet plot of 11 joints on the summit of Beacon Hill, along with a contour graph of the associated poles. What follows now is some background information about the faults in the region. The Hollywood Fault, a major fault, ruptured within the last six to eleven thousand years, and has a recurrence interval of perhaps ten thousand years, and a slip rate of 1.
It also ruptured between one and two thousand years ago, with a recurrence interval of three to four-and-a-half thousand years, and a slip rate of 1. An earthquake in the surrounding area is likely, but perhaps not for a thousand years. Data were gathered with a Silva Ranger, whose declination readings are less precise than Brunton transits, but are much easier to take readings with for a novice. The stereonets were generated using a free academic application available on the internet, Stereonet 6.
See Figures 11 and 12, which show examples. For some faults there are slickenlines present, plus a characteristic planar undulation. Fault gouge can be found both within the obvious faults and nearby. Much of the gouge is carbonate—it reacts with acid. Figure This fault plane is depicted as Fault 3 in Figure The planes of all three faults are intersplaying nearby Helman, c. The cleft of the fault points towards the Verdugo Mountains Helman, b. Figure 13 shows the converging of three of faults on the Lower Beacon Trail, and though all three faults interplane with each other, the major geometry can be worked out, both with slickenlines and based on the shape of the clefts.
The hills in the center of the image, just below the dashed lines of the Eagle Rock Fault, are Glassell Park. Mount Washington is the elevated area adjacent to the south of this. The white rectangle represents the satellite image inset.
Of the three faults, the one labeled Fault 3 is the most impressive. Looking out to the east, the sloping edge of Adams Hill lies directly opposite, and is very clear. This edge forms the northeast boundary of the high terrain called Glassell Park, and Highland Park lies beyond.
Fault 3 perhaps connects with the Eagle Rock Fault, which runs through the foothills just to the north of that city. It does not seem to connect with the Raymond Fault, which runs more southerly, through Mount Washington Figure Fault 2 faces the interchange and an unnamed fault listed on the California Fault Activity Map, probably intended to be part of the Santa Monica Fault Zone.
The line of sight lands directly at the notch where the freeway interchange is situated, and to the fault which underlies Chevy Chase Dr, near the city of Eagle Rock. Figure 15 shows what author has labeled Fault 1 in Figure A large tree sits along its path. It strikes at N20E.
Looking towards Glendale from the Lower Beacon Trail. It is about 4. The cave is a good marker for the spot. Its semimajor axis follows the bedding of the surrounding rock.
My opinion is that this cave is man-made, the start of a mine. Whatever waters percolate through the faults might carry something of economic worth to deposit. The camera is facing SW, and a Silva Ranger transit is open in front of the cave, on the right, for scale Helman, c. The author was not able to find Riedel shears with which to definitively say, and slickenlines seemed unreliable.
Much of the rock is quite loose, and the opposite faces do not have obvious markers. There are also three or more fault exposures which can be easily found on the Fern Canyon Trail facing north and northeast, towards the Verdugo Mountains, and some face towards the same notch as Fault 1. There are undoubtedly other fault traces present in Griffith Park.
The axis is the higher, and the limbs of the fold are the lower parts of the structure. The high part, or the crest of the fold, is parallel to its axis. Rocks to the northeast of the axis dip to the northeast, and rocks to the southwest dip to the southwest.
The anticline is underlain by a blind thrust fault, similar to the one which caused the Northridge earthquake Oskin et al. There is, for example, a small synclinal fold that can be seen adjacent to the summit of Beacon Hill, to the west, near the Upper Beacon Trail. The outcropping rock is only a few feet across.
The timing of the fold is current as uplift is going on presently Oskin et al. That which formed the Elysian Park Anticline formed the geologic structures here, and the compressive forces driving the motion along the Hollywood and Raymond Faults have a similar orientation. Many of the beds on its northern and eastern faces dip to the northwest. Bedding planes are often easy to measure.
There are no corresponding southwestern-dipping beds. Their absence may give credence to an inferred extension of Fault 1 south along the western edge of the Elysian Hills. Regional Tectonism It is perhaps not hard to underestimate how tectonically active the Southern California region is, but faults are subtle structures.
They are subtle enough for people to build houses next to them, and generally walk past even a well-exposed surface. However, people do notice earthquakes. Within historic times, there have been more than 50 earthquakes in Southern California with magnitudes equal to or greater than 4.
One can look out from the vantage in Griffith Park and perhaps see that far. The recent earthquake there, like the Northridge earthquake, was caused by a previously unknown thrust fault, a blind thrust fault. Conclusion Griffith Park is at the same time interesting, accessible, and pointed, and therefore a good place to bring a class of K, college, or university students.
It has the added benefit of being quite close to much of the city. It is on the bus lines, but may take a very long time to reach. From Long Beach, for example, it takes 3 hours each way, so driving is more reasonable.
The rest is likely to also have interesting features, and these will likewise be valuable for introducing people to the geology of Southern California. There are certainly more features waiting to be discovered. This article may serve as a model for what is possible to put together.
0コメント