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The Amboy Crater
by Bill Hampton
A little less than an hour's drive from 29 Palms out along Amboy Road there comes into view a notable, if not beautiful geological phenomenon, the Amboy Volcano Crater. It is located about three miles west of the
little desert Town of Amboy. The crater is mostly black in color and reaches a height of 246 feet at its top and 1508 feet around its base. It is said to be about 6000 to 50,000 years old. However some estimates
give a much more recent date of eruption of just 1500 years ago.
The crater sits in a vast lava field over 43 square miles in size covered with countless pieces of lava rock. It is made up of four cinder cones nestled together inside of each other.
The Amboy Crater is called a cinder cone because it is composed entirely of lava build-up and igneous rock spewed out during volcanic eruptions - some of these eruptions being so violent as to hurl huge red-hot
boulders, called bombs, hundreds of yards from the crater. Near to the crater there are walls of shinny black lava.
The crater lies about a mile south of Route 66. There is a dirt road that leads to it but which becomes rocky and rough toward the crater. Portions of it probably require the use of an off-road or a high wheel base
vehicle. But a 15-minute walk will bring visitors to the crater without the need of wheeled transportation.
Visitors can climb to the top of the crater along a trail which leads up from its west side. There they can look into the mouth of this dormant volcano. The lava there is hilly and reveals crater's last moments of
eruption.
From the top there is an expansive view in each direction. Looking west, Route 66 slowly disappears into the sandy desert and jagged hills. To the north is the view of the Santa Fe railroad where long trains snake
along its tracks. Beyond that the desert hills of the Old Dad Mountains roll on to the north.
Eastward is the Town of Amboy. From the top of the crater it appears like a little toy village. Further along, Route 66 unwinds through pastel hills and vanishes. And to the south, Amboy Road slowly climbs back up
the hills past the Amboy salt flats and over the Sheep Hole Mountains on to Twentynine Palms.
Back before the 1960s, when the 15 and 40 Freeways did not yet exist and Route 66 was well traveled, Amboy was a main hub of stopover activity. Those driving to Las Vegas and points east could take Route 66 through
Amboy. Another route to Las Vegas was by way of the Morongo Basin along Highway 62 through Twentynine Palms out Amboy Road. It seemed that all roads led to Amboy. In those days this little oasis, with its Roy's
Restaurant and service station, enjoyed throngs of traffic and business.
Stories from the 1970s tell of high school students from Twentynine Palms lugging old tires to the top of the crater. There the pranksters rigged a timer, which would ignite the tires after they had climbed down the
crater. It worked and soon thick black smoke was billowing from the top of the crater!
Sojourners who had stopped for refueling and refreshment in Amboy looked to the direction of the crater and saw what surely looked like an eruption. Their eyes must have widened and their mouths dropped at the sight.
Some of them undoubtedly snatched up their food and belongings and hurriedly filed out to their cars. One can imagine the harried husband explaining to his excited wife that they must drive past the crater to get to
Los Angeles but the wife firmly warning him, "No Harold, we are not going near that volcano!"
These days the Amboy Crater is on a kind of seismic short list of those dormant volcanoes along Western North America now being watched for signs of new volcanic activity. The powerful 7.6 Landers Earthquake in 1992
and more recently the Hector Mine Earthquake in 1999, which was centered under the lava beds near the Amboy Crater, give rise to suspicions of new volcanic activity. I spoke to several persons who have
explored in the Amboy area and the lava fields outside of Ludlow about 25 miles to the west. They tell of seeing volcanic venting occurring at both of these locations. The venting appeared as steamy jets with
the smell of sulphur gases. One report sites seawater seeping up through fissures created by the earthquakes.
Another discovery revealed lava flows in this area that had singed an older creosote bush. Judging from the age of the bush and what part of the bush was burned, the lava flow may have
occurred about two hundred years ago.
What would a new eruption of the Amboy crater bring? That would depend on the intensity and length of the eruption. This volcano appears to have undergone fairly energetic
eruptions in the past, which spread lava considerable distances and built a sizeable crater. If an eruption occurred now it might be of similar degree, although not a Mount St. Helens - but certainly a problem.
The U.S. Geological Survey has drawn a map showing perimeters around the Amboy Crater that might be significantly affected by such an eruption.
The southern portion of this parameter borders between Landers and Yucca Valley and includes the northern portions of Joshua Tree and Twentynine Palms. The Marine Corps Base falls almost entirely into this region. Communities within this perimeter would be harried by drifting smoke, cinder particles and volcanic odors. However, dangerous falling debris would not likely reach the Morongo Basin as lava pieces would probably not be propelled more than a mile from the eruption. Even copious flows of lava would remain in the lower valley at Amboy and not climb the 2500 feet up to the Hi-Desert.
The prevailing winds from the west would doubtless carry smoky skies into the resorts of Laughlin and Lake Havasu just over the California state line. And a south wind would scoop up smoke from the volcano and
transport it a 120 miles north to the entertainment giant, Las Vegas.
Since volcanic eruptions can continue for a number of years and even decades, a protracted volcanic event at Amboy would indeed eventually affect all of Southern California. On days when the Santa Ana winds would
blow down into the Los Angeles Basin carrying with it smoke and cinders, surely the complaints would mount about THAT VOLCANO out in the desert. After the first few weeks of novelty, an Amboy eruption would soon be
seen as an ugly nuisance. A long-term eruption might even bring about a negative population growth in Southern California.
Yet for now, the crater may be just twitching in its sleep, not to waken for centuries to come.
But that secret lies deep within the stately crater. As for my own visit to the Amboy crater, I found it to be a rewarding experience providing a glimpse into a unique and beautiful part of our desert's history.
Writer Bill Hampton lives in the Morongo Basin. This expanded version of a story originally prepared for Z107.7 FM radio appeared in The Sun Runner Magazine, December 2000.
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