Answer:
1-California earthquakes are caused by the movement of huge blocks of the earth's crust. Southern California is located on the border between the Pacific and North American tectonic plates. These large sections of the earth's crust (the North American plate extends east to Iceland while the Pacific plate extends west to Japan) are moving laterally. The Pacific plate is moving northwest, scraping horizontally, along the North American side at a rate of 50 mm (2 inches) per year. About two-thirds of these 50 mm per year occurred on the San fault Andrés and some parallel faults - the San Jacinto, Elsinore and Imperial faults (see map). These four faults are among the fastest moving and are therefore the most dangerous in Southern California. Over time, these four faults produce about half of the specific tremors in our region.
However, this is not the whole picture. Much of the plate movement in Southern California is not parallel to the San Andrés fault as in Central and Northern California. Between the southern end of the San Joaquín Valley and the San Bernardino Mountains, in the so-called "great bend", the San Andrés fault runs in a more western direction.
Where the fault bends, the movement of the plates is complicated. The plates, from the Pacific and North America, are pushed against each other, compressing the Earth's crust, thus creating the mountains of Southern California and producing faults and tremors. While the approximately 300 faults are shorter and slower than the previous four faults, more than half of the significant tremors in Southern California occasionally occur.
2-The movement between the plates over the San Andrés fault of 33 millimeters (1.3 inches) per year is more or less the speed with which their nails grow. As a result, the Los Angeles City Hall is now 2.7 meters (9 feet) closer to San Francisco than when it was founded in 1924. It would take about 2 million years (geologically speaking) for its nails to extend 100 kilometers (60 miles) from San Bernardino to Palmdale. It took many millions of years of motion over the faults (earthquakes) to form the current Southern California landscape.
Therefore, as a deduction and a quick answer, it is already being said that in just two million years, their nails will extend 100km.
3-The plates on our planet's surface move due to the intense heat in the Earth's core, which causes molten rock to move inside the mantle. Rocks move in a pattern known as a convection cell, which is formed when a material emerges, cools, and eventually sinks.
Step-by-step explanation:
The origin of the movement of the plates is in material currents that occur in the mantle, the so-called convection currents, and above all, in the force of gravity. Convection currents are produced by differences in temperature and density, so that the warmer materials weigh less and rise, and the colder materials are denser, heavier, and descend.
The mantle, although solid, behaves like a plastic or ductile material, that is, it deforms and stretches without breaking, due to the high temperatures at which it is found, especially the lower mantle.
In deep areas the mantle makes contact with the nucleus, the heat is very intense, that is why large rock masses partially melt and as they are lighter they slowly rise up through the mantle, producing updrafts of hot materials, feathers or plumes thermal. Some of them reach the lithosphere, cross it and contribute to the fragmentation of the continents.
In oceanic trenches, large fragments of cold oceanic lithosphere sink into the mantle, thus causing downdrafts to reach the base of the mantle.
The updrafts and downdrafts of the mantle could explain the movement of the plates, acting as a kind of "roller" that moved them.