Dhe greyish-beige sand runs through your fingers. It is finer than ordinary sand, like dust. You hardly feel him. According to Bob Gross, this sand here in California’s Coachella Valley is the product of huge millstones – “the largest on earth,” says the naturalist guide, who knows the area like the back of his hand.
Gross, who takes his guests on a day-to-day tour of discovery in this geographically very special area in a jeep, means this very seriously. Finally, he speaks of the San Andreas Fault: Here, the Pacific Plate and the North American Plate have literally been rubbing against each other for millions of years – like two millstones, only on a continental scale.
The chasm is 1,300 kilometers long, stretching from Lake Salton in the Colorado Desert on the border with Mexico to Humboldt County in northern California. Los Angeles and San Francisco, but also Palm Springs in the Coachella Valley, where Gross does his tours, are right in the middle. The fissure marks one of the few plate boundaries that run directly on a continent. The others are mostly found at the bottom of the sea.
Source: Infographic WORLD
As part of the Pacific Ring of Fire, the San Andreas Fissure is one of the most geologically unstable regions in the world, explains Gross. The Ring of Fire region, which stretches along the coasts of the Pacific Ocean, contains over 450 active or dormant volcanoes; around 90 percent of all earthquakes in the world occur here.
California doesn’t have any active volcanoes, but it does have the “constant rumbling in the stomach” – this is how Gross describes the plate tectonics and the knowledge of the inhabitants of the risk of natural forces to which they are exposed every day.
The San Andreas Fault stretches a good 1300 kilometers through the US state of California
Quelle: pa/Mary Evans Picture Library/Francois Gohier/ardea.com
The two plates are moving in opposite directions – the North American plate is drifting south and the Pacific plate is drifting north. The annual shift is five centimeters, says Gross. However, it does not happen evenly: “On the contrary – some sections get stuck and stick together for a while.”
If these suddenly separate from each other, an earthquake occurs. This happens 200 times a week in the San Andreas Fault alone. However, most of these tremors are so weak that people living in the region hardly notice them. But if the plates suddenly shift several meters from each other, it has serious consequences – like in the 1906 earthquake in San Francisco, which killed more than 3,000 people.
The jeep rattles through the quiet valley in California
Even if the slabs are constantly in motion: To the human eye, the landscapes that the gigantic grinding stones continuously create appear more like silent, sometimes almost frozen witnesses. The fine dust whirls up as the red jeep rattles through the otherwise quiet valley. The path gets narrower and narrower, the high rocks build up on the sides like warning guards.
Views of the Coachella Valley and the San Andreas Fault
Which: Getty Images/Peter Unger
Soon the sun can no longer be seen, shadows swallow up the bright colors, and the deep blue sky is only a narrow strip at the zenith. Soon you can only continue on foot, because the rock walls are now close together. “These rocks were also made from this powder, which has hardened over the millennia,” explains nature guide Gross.
And so the rock powder plays its very own role in the cycle of life: it penetrates every crack in the jeep, in sandals, in hair and as an involuntary souvenir in backpacks and travel bags. But it is so fine that even water can make it impenetrable.
Due to the fine rock powder, the water cannot seep into the earth’s interior, which is why the area here is very fertile
Source: Christiane Flechtner
“This pile of powder that forms here behaves like flour in a cake batter,” says Gross. In fact, some rock formations look like huge masses of dough. Gross thinks, however, that the water collects like milk or eggs in a bowl and makes the desert fertile in these places: “That’s why a green band runs through the barren, dry and actually hostile rock and desert landscape – a real blessing for the living beings in this area, they always find water, plants and fruits.”
Native Americans used the plants in the Coachella Valley
The Native Americans already appreciated this special feature: the Cahuilla, who lived here 2000 to 3000 years ago, found not only water but also many plant species from which they could feed. These include the California Washington palm, whose black berries they ate and whose palm fronds they used to build huts, or the sweet-tasting legumes of the honey mesquite shrub.
“The legumes dried and ground the cahuillas and turned the flour into a protein-rich sweet tortilla,” explains Gross, showing one of the bean-like fruits. A large grinding stone on a hill above the village still bears witness to this activity. “By the way, the thorns of this shrub were used as tattoo needles,” says Gross.
The Cahuillas once made a protein-packed tortilla from the sweet-tasting legumes of the honey mesquite bush
Quelle: Getty Images/Darrell Gulin
Today, around 90-000 people live in the Coachella Valley, including some descendants of the Cahuilla Indigenous people. Of the nine cities, Palm Springs is the best known – also because many movie stars settled here who, unlike in Los Angeles or Hollywood, did not have to fear paparazzi and at the same time were able to keep a 100-mile agreement.
“Actors had to be a certain distance from Hollywood to be able to get to the set quickly,” explains Gross. Frank Sinatra, Clark Gable, Greta Garbo, Humphrey Bogart, Marlene Dietrich, Marilyn Monroe and Dean Martin were a regular sight in the desert city. Were you afraid of earthquakes?
From the gap between the rock faces, Gross and his guests hike back to the jeep. What will it be like here in a million years? What is just the blink of an eye for the history of our planet is an incredibly long time for humans. With this site visit to the San Andreas fault, the imagination for geological processes has grown – that was geography lessons with the best visual material!
The jeep tours, some with small hikes, cost from the equivalent of around 130 euros per person with at least four guests. If you want to travel privately with friends or family in one of the red jeeps, you pay 155 euros per person (red-jeep.com). Alternatively, the geologically interesting desert landscape of the Coachella Valley can also be explored in a covered wagon (coveredwagontours.com), from 70 euros per person. More info at visitgreaterpalmsprings.com.
Participation in the trip was supported by Visit Greater Palm Springs. Our standards of transparency and journalistic independence can be found at axelspringer.com/de/werte/downloads.
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