Getting There: Follow google maps directions to the coordinates below. Once you reach Highway 20, drive until you see milepost 77 and turn right onto the dirt road. This will take you to the Knappers Campsite among many other great spots to pull over and set up camp! The main roads are dirt, but they can be driven on without four wheel drive if they are dry. If it has been raining, they could be muddy and you may need a four wheel drive vehicle. The side roads, which lead to some cool deposits, would be best with a 4 wheel drive car, or at least a car with high clearance. You can always hike to the spots as well!
Crack in the Ground, or more accurately, volcanic fissure in the ground, resembles a slot canyon - Pacific Northwest style. A pair of igneous cliffs covered in moss stretch up to 70 feet tall from the fissure's bottom, separated by only arm's width in some sections. Birds sail up and down its length, occasionally tending to their nests in its walls. The bottom of the crack, sometimes up to 20 degrees cooler than the surface, can keep ice frozen in the spring.
Water movement in aquifers is highly dependent of the permeability of the aquifer material. Permeable material contains interconnected cracks or spaces that are both numerous enough and large enough to allow water to move freely. In some permeable materials groundwater may move several meters in a day; in other places, it moves only a few centimeters in a century. Groundwater moves very slowly through relatively impermeable materials such as clay and shale. (Source: Environment Canada)
This map shows the liquefaction hazard in the communities of Alameda, Berkeley, Emeryville, Oakland, and Piedmont for a magnitude 7.1 earthquake on the Hayward fault. The map predicts the approximate percentage of each designated area that will liquefy and show surface manifestations of liquefaction such as sand boils and ground cracking. Liquefaction is a phenomenon that is caused by earthquake shaking. Wet sand can become liquid-like when strongly shaken. The liquefied sand may flow and the ground may crack and move causing damage to surface structures and underground utilities. The map depicts the hazard at a regional scale and should not be used for site-specific design and consideration. Subsurface conditions can vary abruptly and borings are required to address the hazard at a given location.
It is difficult to visualize water underground. Some people believe that ground water collects in underground lakes or flows in underground rivers. In fact, ground water is simply the subsurface water that fully saturates pores or cracks in soils and rocks. Ground water is replenished by precipitation and, depending on the local climate and geology, is unevenly distributed in both quantity and quality. When rain falls or snow melts, some of the water evaporates, some is transpired by plants, some flows overland and collects in streams, and some infiltrates into the pores or cracks of the soil and rocks. The first water that enters the soil replaces water that has been evaporated or used by plants during a preceding dry period. Between the land surface and the aquifer water is a zone that hydrologists call the unsaturated zone. In this unsaturated zone, there usually is at least a little water, mostly in smaller openings of the soil and rock; the larger openings usually contain air instead of water. After a significant rain, the zone may be almost saturated; after a long dry spell, it may be almost dry. Some water is held in the unsaturated zone by molecular attraction, and it will not flow toward or enter a well. Similar forces hold enough water in a wet towel to make it feel damp after it has stopped dripping.
Aquifers can be replenished artificially. For example, large volumes of ground water used for air conditioning are returned to aquifers through recharge wells on Long Island, New York. Aquifers may be artificially recharged in two main ways: One way is to spread water over the land in pits, furrows, or ditches, or to erect small dams in stream channels to detain and deflect surface runoff, thereby allowing it to infiltrate to the aquifer; the other way is to construct recharge wells and inject water directly into an aquifer as shown on page 10. The latter is a more expensive method but may be justified where the spreading method is not feasible. Although some artificial-recharge projects have been successful, others have been disappointments; there is still much to be learned about different ground-water environments and their receptivity to artificial-recharge practices. A well, in simple concept, may be regarded as nothing more than an extra large pore in the rock. A well dug or drilled into saturated rocks will fill with water approximately to the level of the water table. If water is pumped from a well, gravity will force water to move from the saturated rocks into the well to replace the pumped water. This leads to the question: Will water be forced in fast enough under a pumping stress to assure a continuing water supply? Some rock, such as clay or solid granite, may have only a few hairline cracks through which water can move. Obviously, such rocks transmit only small quantities of water and are poor aquifers. By comparison, rocks such as fractured sandstones and cavernous limestone have large connected openings that permit water to move more freely; such rocks transmit larger quantities of water and are good aquifers. The amounts of water that an aquifer will yield to a well may range from a few hundred gallons a day to as much as several million gallons a day.