Mud Volcanoes, Faults and Earthquakes of the Colorado Delta Before the Twentieth Century

By CARL L. STRAND
La Siesta Press La Frontera Awards
San Diego History Center 1980 Institute of History

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THE COLORADO DELTA LIES within one of the most geologically active regions of the earth. Four million years ago, the Gulf of California extended far north into what is now the Coachella Valley. Late Cenozoic uplift within the Cordilleran mountain belt probably shifted the crest of the continental divide some 250 Kilometers to the northeast. This shift increased the size of the Colorado River Basin and greatly increased the volume of flow in the river. The lower portion of the basin contributes only ten percent of the river's water, and as successive Pleistocene glacial episodes hastened the entrenchment of the Colorado, tremendous volumes of sediment spread across the floor of the gulf to form a barrier, perhaps synchronous with tectonic uplift.1 Since the formation of the delta, the Colorado's course has periodically shifted so that fresh water sometimes filled the land-locked northern basin.

In 1853, William Blake became the first person to recognize the freshwater characteristics of shells in the upper layers of the Colorado Desert.2 Blake found many of the old shorelines left by this vast body of fresh water which he later named Lake Cahuilla.3 Since Indians of the region say that the water used to extend from mountain to mountain, Lake Cahuilla may have been filled only a few hundred years ago. About forty feet above sealevel, at the head of the New River, the lowest point along the delta's ridge determined the size of Lake Cahuilla. Volcano Lake sat on top of the divide formed by the gently sloping delta. Hardy's Colorado, which also originated from Volcano Lake, took a southerly course towards the gulf. Volcano Lake was named for its close proximity to the Pleistocene volcano known today as Cerro Prieto. An explorer of the nineteenth century may have recognized this prominent landmark rising some 600 feet above the flat deltaic plain, under a variety of names (Mt. Purdy, Three Peaks, Black Butte, or just plain Black Mountain).

Complex interaction between the Pacific and North American Plates is indicated by the young spreading center in the Gulf of California, the northwest-trending series of right-lateral, strike-slip faults en echelon in the Salton Trough, and the lofty mountain ranges of Southern and Baja California. When the East Pacific Rise extended northward some 5 million years before present, Baja California separated from the Mexican mainland, and the Gulf of California appeared. The plate boundary between the Pacific and North American Plates transformed into an active spreading center within the present-day gulf. The sediment-filled extension of the Gulf of California is known as the Salton Trough. Heat flows more than twice the value of the oceanic average have been measured in the gulf. They establish a positive heatflow anomaly that coincides with the East Pacific Rise. As they extend northward into the Salton Trough, two areas of very high heat flow, one near Cerro Prieto and the other at the south end of the Salton Sea, measure four to ten times the average value.4

Cerro Prieto, an extrusive plug composed chiefly of rhyo-dacite,5 was involved in some late eruptive activity. F.L. Barnard placed the age of Cerro Prieto between 10,000 and 250,000 years old. Both active and extinct mud volcanoes have been found along a line which trends northwesterly through Cerro Prieto.6 This feature, known today as the Cerro Prieto Fault, has been called the San Jacinto Fault on older maps. The granitic Cretaceous basement lies much deeper to the east of this fault, which allows Colorado River water to percolate to great depths. As heat radiates from basement rocks lying above the postulated intrusive body, or point source, it heats water, and this process of convection causes the fluids to rise to the surface, resulting in the formation of various hot spring phenomena along the fault zone.

There are five rhyolitic domes which form a northeast-trending arch about five miles long at the southeastern edge of the Salton Sea. These domes- Obsidian Butte, Salton Dome, Pumice Buttes, (two separate domes joined by reworked pumice and volcanic sediments), and Mullet Island7- have been dated as being about 16,000 years old.8 Similar intrusive bodies are thought to underlie areas southeast of the Salton Domes, as well as at Cerro Prieto.9 Mud volcanoes are found along a line extending southeast from Mullet Island, while mud pots are found to the northwest along the same line.10 Before the 1905-1907 flood formed the Salton Sea, early explorers found an extensive group of mud volcanoes, geysers and hot springs where submerged mud pots subsequently existed. Expeditions to the volcanoes before their submergence in May, 1906, included those of J.L. Le Conte and Major S.J. Heintzelman in 185011, R.C. Matthewson in 185512, J.A. Veatch in 185713, H.G. Hanks in188114 and G.W. James in 1906.15 Although no reports have been found that these mud volcanoes became active as a result of any pre-1900 earthquake, the mud volcanoes located a few miles southeast of Cerro Prieto were quite active following major earth-quakes in 1852, 1891 and 1892.

The first Spanish expedition to reach Baja California via an overland route from Sonora was the group of twenty-five soldiers led by captain Melchior Díaz.16 At the head of the gulf, Díaz found letters which had been written two months earlier by Hernando de Alarcón and buried at the foot of a tree indicating that this was not a good place to attempt to cross the river. Díaz proceeded upstream to a place where his party could cross safely. Venturing down the western side of the Colorado, he and his men followed the only good route, which brought them to the vicinity of Cerro Prieto in late December 1540. "They came to some sand banks of hot ashes which it was impossible to cross without being drowned as in the sea. The ground they were standing on trembled like a sheet of paper, so that it seemed as if there were lakes underneath them. It seemed wonderful and like something infernal, for the ashes to bubble up here in several places. They had gone away from this place, on account of the danger they seemed to be in and the lack of water."17

The first mention of an earthquake that likely orginated in the Colorado Delta is found in the diary of Friar Eixarch.18 Eixarch did not venture into the delta region himself, but he was visiting with Indians who went there frequently. Eixarch was encamped at the future site of Fort Yuma, along with a Yuman chief named Palma. The entry for April 25,1776, tells us: "At night there was an earthquake, but it was of short duration. Since I had never experienced such a thing, I was frightened to see how the hill shook. Palma told me that it always does this whenever the river wishes to rise, saying that the earth usually trembles three or four times." The entry for April 26 adds: "About nine o'clock in the forenoon the earthquake was repeated, although very lightly." This short sequence of shocks probably orginated in the delta region, possibly along the Cerro Prieto Fault. One hundred and fifty years later, engineers of the area also had the impression that the frequency of minor quakes increased during the annual overflows of the summer. F.B. Kniffen suggested that while the added burden at those times was great, it was probably effective only in causing "superficial readjustments in the alluvium," without having any significant control over deep-seated movements.19

The first dramatic display of the mud volcanoes in historic times was triggered by the earthquake of November 29, 1852.20 On that day, at twenty minutes past noon, a violent quake was felt at Fort Yuma. "The most extraordinary circumstance was down the river [from the fort] in a W.S.W. direction some 20 or 25 miles in a straight line where immense columns of white steam rose to a great height."21 "The appearance of this column with its narrow base and its wide expanded top was most beautiful; it was supposed to be the steam arising from a hot spring which had just found its way to the surface. This column of steam lasted but a few minutes. Twice within a quarter of an hour two much smaller columns were seen to arise and disappear."22

Again, on the morning of December 7, "a large column of steam was seen to rise from the same point seen the other day. It was in two jets in close succession."23 Several large jets of steam were seen again on the 10th and several more on the 11th. Major Heintzelman decided to make a journey to the source of the steam jets and left with a party of five on the morning of the 12th, returning one week later. What they saw on their trip amazed them all:

The ground is quite flat and there are some hundred or more orifices emitting steam and gasses; some rising out of conical hillocks of mud, from a few inches to 8 or 10 feet high. The principal craters are in ponds of very liquid black mud, one containing three or four cones of an oval form and the others only a few yards across. The principal one bubbles all the time, but every ten or 15 minutes on an average there is a grand eruption throwing up the mud from 60 to 70 feet into the air and the steam and gasses rising many hundreds. The first jet seen on the 29th Nov. must have been 1000 feet high, as it was seen at least 50 miles in a straight line and thus appeared to rise above the tops of the coast range of mountains in rear. At these successive eruptions the pond is lashed into large waves which break like the surf on the shore throwing the mud high in the air. The beautiful snowy steam rising from the black lake below and inlaid with dark streaks and drips has a magnificent effect. Then successive eruptions are accompanied with a rumbling sound, at a distance resembling the report of heavy cannon.

The water in the larger fount was at 118, and the smaller 135 and in a bubbling mud crater 120. The banks of the principal pond are on two sides from 30 to 60 feet high and encrusted with a white and in places yellowish and red incrustation. . . .The smaller orifices emit a constant stream of steam, or like the half interrupted escape of steam from a small escape pipe to a steam engine. The whole is very similar to the volcano I visited two years ago [see White]24, about 40 miles north of the road from Vallecitos to this place, on the great desert.25

The Major's diary entry for January 10, 1853, reads: "The volcano has been active again. . .The steam has been escaping in large volumes. One was seen high threw the mountains beyond." The entry for March 19,1853, reads: "Andrews says he saw more larger and big continued jets of steam rising in the direction of the volcano as he was passing from New River to the 'Alamo Mucho.' " Aftershocks were noted by Major Heintzelman through September 5, 1853, and occurred on all the days that steam jets were seen. It has been deduced that the curvature of the earth requires an object to be at least 800 feet in height above the volcanoes in order to be seen by an observer at Fort Yuma, which was situated on a knob some 100 feet above the desert plain.26 Thus, all the steam jets seen from the fort probably shot over 1000 feet high. The steam column which "rose to a great height" on November 29 must have risen considerably higher than that. In case one was wondering whether the Major was all excited about the earthquake business, he need look no further than the diary entry for December 24, 1852: "... .This is the second dull Christmas for me at this place.. .A little before ten last night we had a considerable shock of an earthquake, lasted near half a minute...."27

In 1855 and 1856, the mud volcano region again burst into extraordinary activity. According to one of Dr. Matthewson's reports, "There can be no doubt there is a volcano in that part of Lower California. In the months of October and November, 1855, he had seen it plainly from the mountain ridge that runs from San Bernardino and touches the Colorado river above Chinnepoya [location unidentified]; and others had told him of it. On September 2d, 1856, going down the Colorado river in a steamer, about forty miles before reaching the mouth and due west some fifty miles, Captain Brady saw what he considered to be a volcano in a state of eruption; the smoke was very plain, emerging from the very top of one of the highest peaks. Calling the attention of the purser, Mr. John B. Dow, the latter said he had seen the smoke in that direction about three months before, and the boatman had often been told by the Cocapas, who live on the lower river, that 'there was a mountain on fire' in that part of Lower California. Later in the month, Captain Brady saw it again, from Alamo Mocho, a point about midway between the Colorado river and New river, on the usually travelled road to San Diego; it appeared to be about 40 or 50 miles due south of Alamo Mocho, plainly in sight, shooting up into the air a dense column of very black smoke, by the upper current spread out into the shape of a cloud."28

The columns of black smoke seen indicate renewed eruptions at the Cerro Prieto mud volcanoes. The smoke seen "later in the month" was possibly synchronous with the strong earthquake felt in San Diego County on September 20,1856."29 About the time of the 1856 earthquake, much curiosity was aroused in San Diego "as to the existence of a volcano in eruption, in the Sierra of Santa Catarina [a former name for the Sierra Juárez] or of San Pedro Mártir."30

A party of prospectors venturing into the area in 1872 to examine the large deposit of sulphur some twenty miles southwest of the volcanoes, took a side trip to the volcanoes and described them as follows:

In the midst of a desert plain are thousands of little mud volcanoes, covering an area of 300 or 400 acres. In the centre of these miniature volcanoes is an air hole through which the steam and gases escape in puffs, with a noise similar to that made by the exhaust pipe of a steam engine. In one place there is a vast cauldron of boiling mud, about ten feet below the general surface, with perpendicular walls, and is about 200 feet in diameter. The mud is boiling at a furious rate continually. The ground in the vicinity is very hot, so that one must have thick boots to walk over it. In many places the ground is shaky, and one must be careful where he treads. In other places the ground is covered with sulphur deposits a foot in thickness.31

In 1876, Lt. E. Bergland and a side party from a government surveying expedition visited the mud volcanoes and left a more detailed account.

The ground within an area of 200 by 500 yards is covered with large and small craters formed from the mud which had been thrown up into conical mounds. These mounds vary in height from 3 to 6 feet, and in diameter, at the base, from 5 to 20 feet. Some have large open craters, within which the hot mud can be seen constantly boiling and bubbling. At short intervals columns of mud are thrown up to the height of 4 to 6 feet, but no regularity in the pulsations could be discovered, nor did they occur at the same instant in the different craters. The smaller cones had small openings al the apex, from which issued sulphurous vapor with a hissing noise. The center of this area was occupied by a lake of boiling mud, all parts of whose surface were constantly agitated, and from which the mud was occasionally thrown up several feet in height. A large mound situated some 200 yards to the southeast of the mud lake appears to have been thrown up by this volcanic action. The crust is composed principally of sulphur, much of which occurs as pure crystals. It is not in action now, but the hollow sound one hears when walking over it seems to indicate that the mound is a hardened crust with a partly-filled interior which possibly communicates with the active volcanoes. The liquid mud is black, but on drying it becomes gray. . .The surface of the ground between Mount Purdy and the mud volcanoes is dotted over with extinct solfataras, with here and there one from which hot vapor issues. A few were also observed east of Mount Purdy. Indians living in the vicinity and old white settlers say that at night flame is seen issuing from these volcanoes, and sometimes high columns of steam. This usually occurs during an overflow of the river.32

A series of earthquakes shook the Salton Trough during the first half of November, 1875. They culminated in a strong shock on the afternoon of the 15th and caused parts of the old adobe stage stations at Gardner's Wells and New River to be thrown down, as well as the adobe stable and corral at Indian Wells.33

Col. David K. Allen, who became the editor of the Yuma Arizona Sentinel in November, 1890, was the first person who tried to publicize the mud volcanoes.34 Allen gave his readers an excellent overview of the region which describes the larger volcanoes. He called them:

. . . the masters of the place, the monarchs of the age, 10 to 15 feet in diameter, and an old monarch of the plains, 40 by 100 feet. Some of these remain quiet for hours, others for minutes, while others boil quietly for days, and then, as if the steam and gases of the universe were bottled up, break forth hurling hundreds, yes, thousands of tons of boiling mud hundreds of feet into the air, with a force that shakes the ground for a long distance away. . . You can crawl up the sides of some of the cones and look down for 15, 20 and often 30 feet and watch the restless contents as they rise to the top and finally explode, scattering the hot mud and water about for 50 feet or more. Some will be dead for days, perhaps for weeks, when all at once they break out with a roar of a thousand thunders, shaking the hills. The monarch caps them all. With no cone, sides even with the surface of the adjoining land, and a mouth like a lake, filled with restless heaving mud, now almost still, now rolling and puffing, now raising on one side, then lifting itself as if going to roll out and overflow the surface for miles away, then again for awhile quiet, perhaps dead still, then with another roll and a lift shaking the earth for miles around, heaving a vast volume of mud until it almost passes out of sight in the distance."

A pond which Allen named the Lake of Ink was described as being an eighth by a quarter-of-a-mile in dimension, and ranging in temperature from 110 near the edge, to 150 in the center and 216 at 250 feet down. No bottom had ever been found in the middle, past the drop-off. The black water was only four to six feet deep along the twenty-feet wide shelf along the west, south and east sides. "To the bather, the sensation on entering the water is grand, exhilarating to a wonderful degree, so much so that a bath of 10 or 15 minutes makes one feel as if he was under the influence of the very best brandy. . .Whenever the volcanoes rage with anger, the lake follows, and the sight of its maddened waters is well worth seeing." Allen also explained unique methods of mud bathing used by the Indians to remedy various diseases.36 With these articles, Allen established himself as the contemporary authority on the mud volcano region. Being on the best of terms with the Cucapa Indians,37 Allen was free to spend as much time as he wished exploring natural wonders.

Few people were willing to believe that there was room in Baja California for ten-feet high mud volcanoes, multi-colored hot springs and an ink-black lake. Mother Nature verified Allen's story by triggering a powerful earthquake which occurred at 6:03 a.m. on July 30, 1891. It was most likely centered along the Cerro Prieto Fault in the vicinity of Ciudad Lerdo, a small settlement located about sixty miles south of Yuma on the Sonora side of the Colorado River. The Indians and settlers of the delta were so terrified by these shocks and their effects that the truth of their reports is still obscure. The most sensational accounts, which were relayed by Associated Press dispatches, report one hundred-feet tidal waves, a river of bluish-purple fire, a burning mountain of sulphur, violent eruptions of mud volcanoes (which sent columns of black vapor high into the air), and the formation of a large chasm in the bed of the Colorado River.38 These accounts hit the front pages of newspapers all along a coast.

We can never be absolutely certain about this earthquake's true extent, but two expeditions into the delta region sought evidence of its real effects. The first expedition, led by J.J. Stein of the San Francisco Examiner, and the second, led by Colonel Allen of the Arizona Sentinel, both used cameras, giving their accounts some objective credibility.

The Stein expedition left Yuma on August 11 and returned five days later. Stein reached the conclusion that "at both the Cocopah region and Lerdo Colony, an almost phenomenal and dangerous upheaval of the earth's surface took place there during the end of last month."39 Numerous cracks and fissures were found and directly attributed to the earthquake of July 30; the broken shale attested to their recency.

About twenty-five miles above Lerdo, the Stein party saw fissures several hundred feet long and about six to eight inches wide. The western side of the river seemed to have been more severely disturbed, with wider and more frequent cracks and trees thrown down in great numbers. Indians who lived near the Paredones, some twenty miles northwest of Lerdo, told Stein that all of their houses had been thrown down. "In the lowlands, where the ground had been covered with water, when the earth cracked open, boiling hot water was thrown into the air hundreds of feet high.. . . In places the hot water rolled out over the surface for several yards and then flowed back in-to the crevices."40 Further down, some other Indians stated that "great streams of hot water were thrown from the crevices of the earth. "41 When the party reached the recently deserted Indian village of Las Cruces, cracks and fissures could still be seen on the east side, but the brush was so dense that their extent could not be determined. Most of the dwellings had been leveled.

Prior to the earthquake, the Colorado River shifted about three miles to the west of Lerdo.42 About eight miles upstream from Lerdo, where "Salt Creek" apparently refers to the Santa Clara Slough, some 200 feet of a bluff broke off into the river and caused it to switch its course at least 300 yards westward, to form a new channel.43 During the earthquake, a large section about 100 feet high broke off from this bluff.44 Eduardo Andrade wrote his father, General Guillermo Andrade, one of the projectors of the Colonia Lerdo project, that "three cracks, each 500 yards long and 2 feet wide, were formed along the banks of Salt river, and a patch of ground near by was torn up as if by a blast of dynamite."45

About five miles upstream from Lerdo, along the old riverbed and to the west of it, there were found "a number of fissures from eight to twelve inches wide and from 100 to 250 feet in length, in some places partly filled with sand, where there was sand, and in other places with mud and water."46

When they reached Lerdo, the Stein party was told by inhabitants that since shocks had continued all day on the 30th, it was impossible to get near the livestock. The actual structural damage at Lerdo was trifling, especially as compared with earliest reports. Continuing downstream, the party still thought the shocks were "very much more serious and effective on the west side. Dry arroyos opening into the river showed dark, deep opening, of but small width but hundreds of feet in lengh."

It should be kept in mind that the surface to the westward was composed of unconsolidated soil. The party stopped several times to examine the high mesas on the eastern side, whose sand and gravels showed "all the signs of having been shaken up and removed from place to place. In many instances we found deep cavernous pits and deep curs and rifts, of recent formation, into whose fathomless depths the sand and pebbles thrown continued seemingly to fall without stopping. At the highest point on the mesa we had a fair view of the volcano, from which we saw the steam or vapor as it arose from the craters and settled down the plain like a gauzy covering of lace."47

After their Indian guide refused to take them to the mud volcanoes, which could be heard booming in the distance, they secured a wagon back to Yuma upon reaching the ranch of Chester Townsend, about seven miles downstream from Lerdo. Seventeen springs near Townsend's ranch had temporarily changed from very salty to as "sweet and wholesome as that of the Colorado River."48 The fissures made by the earthquake were supposed to be "wider and longer than those of any previous years, as the comparison can readily be made owing to the fact of the crevices caused by earthquakes of years past being still open and unfilled."49

If there was substantial activity at the volcanoes, one would expect to find, upon inspection, that a number of actual physical changes had also occurred there. The Allen expedition affords us such a view. Allen left Yuma on September 12, 1891, and returned November 10. He spent the first month examining a land concession in his role as a licensed civil engineer for the Mexican Government. In mid-October, Allen visited the mud-volcano region and noted changes that had occurred there since his visits in 1890. He had spent much time out on the desert during the first half of 1890, laying out a proposed railroad route from Valle Trinidad to Yuma for the Mexican Land and Colonization Company.50 He found that fifteen volcanoes in the western group, once very active ones, had been almost entirely obliterated. In the northern group, the Giganta and its surroundings were very quiet. In the eastern group of 500 volcanoes, which had been submerged by Volcano Lake, sudden outbursts threw up pebbles, fish, seaweed, sulphur and hot water. To the southern group, "at least 100 grand volcanoes" had been added. "On South Hill, where one year ago no evidence of a volcano existed, the Chief, the grandest of all now to be seen in the southern country, is in active operation, with a crater 100 by 40 feet, and it fumes, smokes and continues to threaten general disaster to the immediate surroundings."51 Due to the overflow of 1891 caused by the flooding of the Gila River in Arizona, Volcano Lake had grown from a semi-circular body of salt water some five by one-half miles in area, to a fresh-water lake some 25 miles long by 12 to 25 miles wide.

Earthquakes have been known to change the behavior of hot springs significantly. For instance, an observer stationed at Yellowstone Park during the Hebgen Lake earthquake of August 17, 1959, once compared the force of that earthquake to a "giant hand which suddenly applied enormous pressure to the rocks beneath the hot springs, forcing water from their conduits in a manner comparable to the squeezing of a sponge.. . .Its jarring served as a trigger to start discharge from hundreds of springs. Had this happened in the daytime, the spectator would have witnessed geyser activity on a scale never even closely approximated since Yellowstone's discovery."52 Earthquakes in the delta region have clearly acted in a similar manner.

On the night of February 23, 1892, a severe earthquake occurred which was felt very strongly from San Quintín to Los Angeles and was also reported as far away as Santa Barbara, Visalia and Needles. Two weeks later, a flurry of mud volcano reports appeared in newsprint. A group of miners felt the earthquake while encamped

"on the lower Laguna Mountains, about midway between San Diego and Yuma, and very close to the Mexican boundary line. When the earthquake occurred, it was felt pretty sharp out there, and as some of us knew something about the country, the first thing we looked for next morning was a sign of a volcano over in the direction of the Cocopah region. But not a sign did we see. On the contrary, the smoke and haze of steam and vapor which had always been seen in that direction had disappeared, and the entire desert was as clear as a mirror. But all that day, rumblings continued and, toward night, a change came. Before night, we could see black smoke, and, two or three hours after dark, we could plainly see a burst of flames. The fires appeared to be about forty miles away from where we were. They were some distance below the Mexican line and over toward the Colorado river, and were evidently in the Cocopah region, where it is well known the mud volcanoes have long existed. The flames were not high in the air, but were close to the level of the desert and seemed to come from pit holes, rather than from mountain tops."53

Mr. Mickle of Campo was at a high elevation when the earthquake occurred. "He saw a dense, black cloud far to the southeast, which spread out like a vast umbrella, and at night saw in the heavens the reflection of a great fire in the same region."54

A Mexican passed through National City with the story that he was on the west side of a range of mountains, on February 23, when "the ground shook fearfully." On the next day, he "climbed to the top of the mountain and looked over [where] on the east side of the Cocopah, many miles from him, a beautiful sight met his eye. It was a continuous large volume of jet black smoke, a mile in length, shooting from the mountain into the air, on the east side of the Colorado.55 Having come near as he cared "to venture, after viewing the unexpected beautiful black streak," he returned to camp.

John McCane and others who lived near Campo verified that the "smoking springs" had been quite active since the earthquake. Much vapor was sent into the air and a rumbling noise was audible for many miles around. One party that approached the mud volcanoes spoke of the ground trembling so that at a distance of 200 yards he became seasick.56 Cucapa Indians stated that the mud volcanoes became very active on the same days as the earthquakes, "and that the views from a distance were grand and magnificent beyond description. The escaping steam vapor and smoke during the day, and the flames by night, rose higher than were ever seen before."57

The cause of the flames can best be accounted for by considering the phenomenon of ignis fatuus, more commonly known as will-ó-the-wisp. Usually seen near bogs, swamps and graveyards right after sunset on a windless night, will-ó-the-wisp consists of flamelike lights which may shine steadily, or flicker erratically, occasionally rising high in the air. The source of these flames is thought to be burning marsh gas largely composed of methane. Hydrogen phosphide, a gas associated with the decay of organic matter, is believed to ignite this marsh gas, which is not spontaneously inflammable. Seeps of natural hydrocarbon gas have been found near the mouth of the Colorado River, but it is not certain whether these gasses are primarily of juvenile origin (i.e., were recently derived from mantle material) or the result of vast amounts of organic material decaying in the delta's sediment. Following a sufficiently large earthquake, any gasses near the active fault zone would find freshly-made conduits to the surface, and in the case of mud volcanoes, their effect might be compared to dozens of gigantic burners burners.

The mud volcanoes took a while to placate themselves, as shown by the following diary extract. "March 23, 1892-I and Geo. was up on a high peak, where we could see a large colum of black smoke rising, it went straight up in the air. It was coming out of the volcano that has been making all the quakes of late. "58 Cucapa Indians were frightened by a short-lived episode of increased activity on the night of May 19, 1892.59 On his way down from Yuma on another land inspection trip, Col. Allen stopped briefly at the mud volcanoes, noting that "the volcanoes were very quiet, but busy building up the cones destroyed by the great earthquake in July last."60

All available evidence suggests that significant fault-trace phenomena did occur along the Cerro Prieto Fault on July 30,1891. Since the extent of those surface effects is still unknown, it would be impossible to state the precise epicenter. Scientists didn't actively seek correlations between fault-trace phenomena and specific earthquakes until after the San Francisco earth-quake of April, 18, 1906.

The earthquake of December 31, 1934, also caused huge fissures to open in the proximity of the Cerro Prieto Fault. Fissures were reported from ten miles north of the gulf to a point one hundred miles down its eastern shore.61 A fault scarp across the tidal flats of the lower Colorado Delta has been discerned in aerial photographs taken by Mexicans in 1935. It appears considerably fresher in those photos than it does in subsequent photographs of the same region.62 Large fissures were formed in the desert about forty miles to the northwest of Cerro Prieto during the 1892 earthquake.63 Isoseismal contours based on an analysis of primary accounts of the 1892 earthquake64 indicate that the very recent scarps which have been mapped along the Laguna Salada Fault65 lie within the zone of highest intensity. Therefore, the epicenter of the 1892 earthquake has been tentatively assigned to the Laguna Salada Fault.66

The mud volcanoes faded from the public forum until June, 1895, when George Neal and Lew Hosgate reported that they had seen a heavy column of black smoke that appeared to ascend from near Cerro Prieto. Their vantage point was from Cañon Tajo, along the eastern escarpment of the Sierra Juárez, and from there they saw the black column shooting high into the air at intervals and heard a booming sound similar to cannonading. "Indians told them that the Cocopah country was on one of its 'tantrums' again, and that the mud volcanoes, gas fissures, hot springs, and fire volcanoes were all at work with more activity than ever before."67

Soon after that, early in 1896, prospectors and railroad men passing through Indio reportedly saw "immense quantities of smoke and steam rising off the desert toward the volcanoes below the Cocopah mountains during the day and a bright light at night."68

Later in 1896, Luman H. Gaskill, widely known for his knowledge of the mountains and deserts of the border region, led a party of eighteen health-seekers to mud volcanoes for therapeutic baths in the Lake of Ink, which the Indians called "Medicine Lake." As thousands of boiling springs spouted mud far into the air, miniature craters could be heard sputtering for miles. Meals were cooked over the little ones, and a cloud of steam hovered over the craters like smoke.69 Natural pools afforded crude, but comfortable, bathing facilities. and at the time, "visitors from Yuma and other [nearby] places. . .more or less familiar with the virtues of these baths. . .praised them to the skies. Rheumatism and kindred ailments have disappeared like magic from the emaciated bodies of pilgrims who have been induced to bathe in the pools of the mud volcano region."70 "Besotted miners and other hard-drinking individuals" went there to "boil themselves out."71 "Any degree of temperature or mineral strength can be enjoyed by the bather in the pools, and some of them are so powerful that a man's body would be eaten up by the minerals in a few hours. A tin cup has been utterly destroyed by immersion in the water for twenty-four hours, and cloth is rendered as fragile as charred paper after being in the water for six hours."72

Although the Cucapas had lived in the vicinity of the mud volcanoes for many generations, and had learned of the health giving properties of baths in the hot mud, they had an awful fear of the region. According to Thomas H. Silsbee, a contemporary authority on the Cucapa tribe, the natives would not pass by without uttering a deep grunt and stamping the ground. Silsbee attributed this behavior to the tradition that "generations ago, before the country was inhabited by any people but the Cocopahs, enemies of the tribe, as well as criminals among their own number, were bound hand and foot and thrown into the mud volcanoes, being received in the depths by the devil."73 Those who frequented the area gave it such names as "hell's half-acre," and just plain "hell." The Cucapas referred to the place as "crust of hell" and "home of the devil".74

The San Jacinto earthquake on Christmas morning, 1899, reportedly caused the geysers "to spout with redoubled force."75 The earthquake of January 23, 1903, was said to have wrecked strongly built adobe houses at Ciudad Lerdo. "Cypriano, the major domo of the settlement, and Bruce Kasbeer's vaqueros, state that at that time trees were swayed so violently as to be broken, men were thrown from their feet, the ground was fissured, the waters of the river were thrown high in the air, and a great smoke arose in the northwest from the volcano springs region."76

One story told that "one of the riders employed by a big cattle company that control(ed) the greater part of the range south of the line decided in a moment of alcoholic inspiration to explore one of (the) uncanny caves along the shore of Volcano Lake. (Those) openings, like the volcanoes themselves, usually discharge(d) vapors, and from some of them hot springs or mud flows issue(d). . . He came out quickly, sobered and shaken, and started for his pony. The crust's too thin in this neighborhood for me, he is reported to have said. 'I don't believe the end of that hole is more than forty feet from hades, and while I'm a fair gambler and only an ordinary sinner, I don't want to take any chances hereabouts. Calexico and the forget-it-water for mine.' "77

A number of explorers visited the mud volcanoes before the flooding of 1909. The massive deposition in the Volcano Lake area which occurred over the next twelve years marked the dawning of a new era. White jets of steam seen from the Cerro Prieto geothermal field by modern-day travelers are a reminder of the black columns of vapor which Indians and pioneers observed in days gone past.

NOTES

1. F.B. Kniffen, "The Natural Landscape of the Colorado Delta," University of California Publications in Geography, Vol. 5, 1932, pp. 187-88.

2. W.P. Blake, "Geological Report", in R.S. Williamson, "Reports of Explorations and Surveys to Ascertain the Most Practicable Route for a Railroad from the Mississippi River to the Pacific Ocean, made in 1853-54," House of Representative Ex. Doc. No. 91, 33rd Congress, 2nd Session, Washington, D.C., Vol. 5, Part 2, 1857, 310 pp.

3. W.P. Blake, "Lake Cahuilla: The Ancient Lake of the Colorado," Out West, Vol. 30, 1909, p. 74.

4. L.J.P. Muffler and D.E. White, "Active Metamorphism of Upper Cenozic Sediments in the Salton Sea Geothermal Field and the Salton Trough, Southeastern California," C.S.A. Bulletin, Vol. 80, 1969, pp. 160-61.

5. P.T. Robinson, Personal communication to Dr. Gordon Gastil, 1971.

6. Kniffen, "Natural Landscape," p. 158.

7. V.C. Kelley and J.L. Soske, "Origin of the Salton Volcanic Domes, Salton Sea, California," journal of Geology, Vol. 44, 1936, pp. 496-509, and P.T. Robinson, W.A. Elders and L.J.P. Muffler, "Quaternary Volcanism in the Salton Sea Geothermal Field, Imperial Valley, California," G.S.A. Bulletin, Vol. 87, 1976, pp. 347-60.

8. Muffler and White, "Active Metamorphism," pp. 160-61.

9. H.A. Espinosa and F. Mooser, "El pozo M-3 del Campo Geotérmico del Cerro Prieto, B.C., México," Asoc. Mex. de Geól Bol, Vol. 16, 1964, pp. 163-77.

10. J.R. McNitt, "Exploration and Development of Geothermal Power in California," California Div. of Mirtes and Geol. Special Report 75, 1963, p. 32.

11. J.L. Le Conte, "Account of Some Volcanic Springs in the Desert of the Colorado in Southern California," American Journal of Science, Second Series, Vol. 19, 1855, pp. 1-6, and J.L. White, "Founder of Fort Yuma: Excerpts from the Diary of Major Samuel P. Heintzelman, U.S.A., 1849-1852" (unpublished M.A. thesis, University of San Diego, 1975), pp. 77 and 85-86.

12. San Diego Herald, December 22, 1855.

13. Ibid., August 1, 1857; J.A. Veatch, "Notes of a visit to the mud volcanoes in the Colorado Desert in the month of July 1857," American Journal of Science, Second Series, Vol. 26, 1858, pp. 288-95; J.A. Veatch, "Salses or mud volcanoes of the Colorado Desert," Hesperian, Vol. 3, No. 5, 1860, pp. 481-89.

14. H.G. Hanks, "Mud Volcanoes and the Colorado Desert," Second Annual Report of the State Mineralogist of California, 1882, pp. 227-38.

15. G.W. James, The Wonders of the Colorado Desert, (Boston: Little, Brown, and Co., 1906), p. 19 amd 81-91.

16. G. Sykes, "The Colorado Delta," American Geog. Soc. Special Publication 19, 1937, p. 9; and R.L. Ives, "Mud Volcanoes of the Salton Depression," Rocks and Minerals,. Vol. 26, 1951, p. 227.

17. G.P. Winship, The Journey of Colorado, (New York: Allerton Book Co., 1922), p. 59.

18. H.E. Bolton, The San Francisco Colony: Diaries of Anza, Font and Eixarch and Narratives by Palou and Moraga, (Berkeley: University of California Press, Vol. 3, 1930), pp. 374-75.

19. Kniffen, "Natural Landscape," p. 158.

20. M.A. Balderman, C.A. Johnson, D.G. Miller and D.L. Schmidt, " The 1852 Fort Yuma Earthquake," Seis. Soc. Amer. Bulletin, Vol. 68, 1978, pp. 1717-29.

21. Major S.J. Heintzelman, Papers, 1849-1852, Copley Library, University of San Diego (microfilm).

22. D.C Agnew, "The 1852 Fort Yuma Earthquake: Two Additional Accounts," Seis. Soc. Amer. Bulletin, Vol. 68 , 1978, p. 1761.

23. Heintzelman Papers.

24. J.L. White, "Major Samuel P. Heintzelman," pp. 77 and 85-86.

25. Heintzelman Papers.

26. Fugro, Inc. "Report of 1852 Fort Yuma Earthquake," Sundesert Nuclear Plant, Preliminary Safety Analysis Report, S.D.G. and E. Sec. 2.5, Vol. 6, App. P, U.S.N.R.C. Docket No. 50-582,-583, 1976, 55 pp.

27. Heintzelman Papers.

28. F.C. Shipek, ed., Lower California Frontier; Articles from the San Diego Union, 1870, (Los Angeles: Dawson's Book Shop, 1965), p. 48.

29. D.C. Agnew, M. Legg, and C. Strand, "Earthquake History of San Diego" in P.L. Abbott and W.J. Elliott, eds., "Earthquakes and Other Perils, San Diego Region, San Diego Assoc. of Geologists Guidebook," 1979, p. 127.

30. San Diego Union, April 21, 1870.

31. Bancroft Scraps, "The Lower Country," Vol. 78, May 26, 1872, The Bancroft Library, Berkeley, University of California, Berkeley.

32. Lt. E. Bergland, "Preliminary Report Upon the Operations of Party No. 3, California Section, Season of 1875-76, With a View to Determine the Feasibility of Diverting the Colorado River for Purposes of Irrigation," Report of the Secretary of War, Vol. 2, Part 3, App B, 1876, pp. 334-36.

33. San Diego Union, November 19, 1875.

34. Arizona Sentinel, November 8, 1890.

35. Ibid., July 25, 1891.

36. Ibid.. August 1, 1891.

37. Lower Californian, August 7, 1890.

38. Los Angeles Evening Express, August 7, 1891, August 8, 1891 and August 9, 1891.

39. San Francisco Examiner, August 21, 1891.

40. Ibid., August 13, 1891.

41. Ibid., August 21, 1891.

42. Arizona Sentinel, July 25, 1891.

43. San Francisco Examiner, August 21, 1891.

44. San Francisco Chronicle, August 14, 1891.

45. San Francisco Examiner, August 13, 1891.

46. Ibid., August 21, 1891.

47. Ibid.

48. Ibid., August 11, 1891.

49. Ibid.

50. Lower Californian, June 19, 1890.

51. San Francisco Examiner, November 11, 1891.

52. G.D. Marler, "Effects of the Hebgen Lake Earthquake of August 17, 1959, on the Hot Springs of the Firehole Geyser Basins, Yellowstone National Park," U.S.C.S. Prof. Paper No. 435-Q,, 1964, p. 186.

53. Lower Californian, March 11, 1892.

54. Riverside Daily Press, March 12, 1892.

55. National City Record, April 7, 1892.

56. Lower Californian, May 6, 1892.

57. Arizona Sentinel, May 7, 1892.

58. S. Cameron, "Extracts from the Diary of Sam Cameron," 1892, Courtesy of Mrs. Flora Harris, Campo, California.

59. Lower Californian, May 26, 1892.

60. Arizona Sentinel, June 18, 1892.

61. United States Bureau of Reclamation, "Record of Earthquakes in the Yuma Area," Special Report, Yuma Projects Office, 1976, pp. 57, 176.

62. R.L. Kovach, C.R. Allen and F. Press, "Geophysical Investigations in the Colorado Delta Region," Journal of Geophysical Research, Vol. 67, No. 7, p. 2852.

63. H.C. Hensley, "The Memoirs of Herbert C. Hensley," (unpublished typed manuscript in the San Diego History Center Library and Manuscripts Collection, 1952), p. 516, and Riverside Daily Press, March 12, 1892.

64. C.L. Strand, "Pre-1900 Earthquakes of Baja California and San Diego County" (unpublished M.S. thesis, San Diego State University, 1980), 336 pp.

65. F.L. Barnard, Structural Geology of the Sierra de los Cucapas, Northeastern Baja California, Mexico, and Imperial County, California, Ph.D. thesis, Boulder, University of Colorado, 1968, (Boulder, Colorado: Associated University Press, 1968), 155 pp.

66. Strand, "Pre-1900 Earthquakes."

67. San Diego Union, June 27, 1895.

68. San Francisco Chronicle, January 6, 1896.

69. Hensley, "Memoirs," p. 726.

70. San Diego Union, August 9, 1896.

71. Hensley, "Memoirs," p. 656.

72. San Diego Union, August 9, 1896.

73. Ibid., November 2, 1896.

74. Ibid., December 1, 1898.

75. Los Angeles Times, January 1, 1900.

76. R.H. Forbes, "The Lower Courses of the Colorado," University of Arizona Monthly, Vol. 14, No. 4, 1906, 226-67.

77. W.C. Mendenhall, "The Colorado Desert," National Geographic Magazine, Vol. 20, No. 8, 1909, p. 701.

THE PHOTOGRAPHS on page 50 and 54-55 are from the Sherman Library, Corona Del Mar. The map is by Don Bufkin. All others are from the San Diego Historical Society's Title Insurance and Trust Collection.