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Sunday, 11 September 2011

Origin of Earthquakes

Origin of Earthquakes

   Earthquakes are common geological phenomenon on planet Earth. Depending on the magnitude, depth (focus) and area of ​​occurrence (epicenter) are also responsible for natural disasters that involve intense destruction of buildings and unfortunately the loss of human lives.

 Destructive earthquake of magnitude 7.9 that hit Sichuan Province, China, 
in May 12, 2008.  Deaths 69,195. Missing 18,392. Injured 374,643.

  Records are known since ancient times and nowadays many studies are done to diagnose areas of risk and try to make predictions, especially by seismological studies.

  It is recognized that there are difficulties in making predictions about when and where an earthquake of great magnitude could occur. 
Could this be due to the fact that there are many studies on the consequences and not about the real causes of earthquakes

  The seismological studies are conducted after the occurrence of an earthquake and, in this case, there is no way to make any predictions,
because it would have been released seismic energy - the bullet had been triggered - and therefore only remains to study the behavior of seismic energy as his intensity, geometry, among others.

   Very little is studied about the real causes of earthquakes. There is a geological paradigm that tries to explain  that earthquakes are accumulated tensions related to fault lines or boundaries of tectonic plates that move. In fact, it would make sense, however because this would occur? What are the causes that influence fault movements? It is noteworthy that there are several areas on the planet with earthquakes positioned in intra-plate situation, not just at the boundaries of these plates. Another situation is try explain explain earthquakes related to conventional subdcution zone as postulated by Plate Tectonics that earthquake sources get deeper under the overriding tectonic plate proceeding away from the trench at a subduction zone, and would delineating the so-called Wadati-Benioff Zone. Some realize that these earthquakes would be formed by friction between plate slabs. Nevertheless, deep gas migration due buckling of continental border also offer an explanation, including associated magmatism also related to decompression due deep faults that form by buckling of shallow crust.
Most earthquakes occur along plate boundaries 
but also occur in intra-plate situation

   The astronomer and astrophysicist Thomas Gold proposed an interesting explanation about the cause of earthquakes. In summary, the earthquakes are related to migration of primordial gases in Earth's interior. Among these gases include mainly methane, nitrogen, helium, radon. If an gas accumulation that reached a critical state pressure could trigger seismic energy with the release and migration of these gases that displace at various crustal levels. Manifestation of these gases are known to be mainly in seismogenic related areas or at the time of occurrence of large earthquakes.
Amount of Helium gas in a shallow well which showed a sharp increase a day before  the earthquake at Loma Prieta on October 17, 1989.

Radon in groundwater before and after the 16 January 1995, Kobe earthquake in Japan (Igarashi et al. 1995)

    Mud volcanoes are closely related to seismically active areas. Their characteristics should be studied to better understanding of earthquakes. There are also many cases where there is a relationship between seismogenic areas and areas of occurrence of oil production, natural gas and black coal. Another known phenomenon, but little is done to intensify studies to predict earthquakes, is the monitoring of radon gas. There are other important phenomena that may be linked to the imminent possibility of occurrence of large earthquakes. May be cited as examples, the formation of large methane clouds, a color change of becoming iridescent clouds. Also change the default behavior of animals, like profuse migration of amphibians (frogs). These animals have sensitive skin and gas migration, even if these upwellings in lakes and swamps are very weak, could disturb the frogs and so they seek refuge escaping with mass migration from their natural habitat. Some animals with highly developed sense of smell might also feel odors emanating gases that would not be perceptible to the human sense of smell.

Tectonic sketch of Italy, distribution of oil and gas occurrences and major earthquakes. This is a remarkable example to show that hydrocarbons (oil and natural gas) merely follow the deep structures and fit perfectly to the major deep thrust faults present in the structural framework of the Apennines chain, the Bradanic trench and  Calabrian Arc which permit migration of hydrocarbons from mantle below to shallower reservoirs above in sedimentary basins. During reactivation of those deep structures natural gases such as methane, helium, nitrogen, radon may be present and,  if gas migration is huge in depths and reach shallow levels in crust, the descompression of deep gases will release seismic energy and increase the probability of occurrence of earthquakes.

Mud volcanoes, Nirano, Italy

Possibly methane clouds 30 mins before the Sichuan earthquake 
in China, May 12th  2008.

Swarm of frogs prior In the days prior to the gigantic earthquake that devastated Sichuan province in China.
   It seems that studies of seismology are based only on the propositions of conventional geology and there's no major advance in order to predict major earthquakes. However, understanding the formation processes of the Earth, the origin of hydrocarbons and natural gas, the manifestation of gases in the earth's surface and its monitoring, combined with conventional studies of seismology and the various precursor signs already known, could certainly contribute with relevance to predict strong earthquakes, thus protecting many lives.

   In summary it is essential to combine studies of the physical properties of the seismic energy with the chemical properties  of earthquakes, i.e. the chemistry of earthquakes, this last one as a possible cause and the first as a consequence of  the phenomenon.

Thomas Gold and its legacy about earthquakes

Earthquakes, Gases, and Earthquake Prediction
Thomas Gold
   Many reports about earthquakes have suggested that the escape of gases was a major effect, both before, during and after the quakes.
   The modern theory has it that some subterranean forces, of unknown origin, gradually build up strains in the crustal rocks, up to the breaking point. The earthquake is then supposed to denote the moment of fracture of that rock.
Many features of earthquakes seem to have no explanation in this theory.
   Why would there be many occasions of multiple large quakes over a period of a few days to months? Would the rock not break in all the locations in which it is already stressed to near breaking point, at the time it is violently shaken? Why would the ground shake sometimes for periods longer than a minute? Why would quakes cause tsunamis, the massive ocean waves? A brief tremor, however fierce, would not have such an effect. Perhaps the modern earthquake research had omitted the consideration of effects due to the sudden movements and the rapid large changes of volume that gases may cause. We shall therefore discuss the huge eruptions that have brought up diamonds, and we might well ask whether there may not be smaller ones much more frequently. Are they the initiating events for earthquakes as well as for volcanic eruptions?
   Eye-witness accounts strongly suggest that gas eruptions are the initiating events, but in modern times not much attention is paid to such information, because it is considered too uncertain. Instead the effects that can be measured with accuracy, such as a gradual increase of the strains in rocks and the relation of this to earthquakes, has now become the main subject of research in this field in the US. The overriding importance of this research would lie in finding a method for the prediction of earthquakes, but no such method has so far been found.
   One city has been successfully evacuated two hours before a massive earthquake, and thereby probably many thousands of lives were saved. This was the city of Haicheng in China, in February of 1975. That prediction was based almost entirely on gas-related phenomena. (See the description in "Eye-witness Accounts of Several Major Earthquakes," this Web site.)
   In the modern geological literature the movement of gases in the crust is rarely considered. Perhaps this is still due to the widespread misconception that no pore-spaces could exist deeper than about 10 km. Even when a most violent volcanic gas explosion has occurred, this is often discussed as due to gases that have come out of solution as the lava is exposed to lower pressure. Why would one not consider that a massive bubble of gas had entered the lava channel and raced to the top?
   Diamonds, a very pure form of carbon, tell us quite a detailed story about the physical and chemical conditions in the earth, below about 150 km, and this information bears on the origin of petroleum. Chemical theory and the experience in making artificial diamonds, show that high pressures of the order of 45 kilobars are needed to produce this dense crystal. Such pressures are found in the Earth only at a depth of 150 kilometers or more, and it is somewhere at such depths that natural diamonds must have been formed. The temperature there exceeds 1000°C.
   The geologic situation in which diamonds occur shows that unusual gigantic eruptions were involved. Although many diamonds are found dispersed in river gravels, the only concentrated deposits are in the rare "pseudovolcanic" structures called "kimberlite pipes." These are deep, vertical shafts, usually filled with a mixture of rock types, including the diamond-bearing rock called kimberlite (Figure 1). Most of the known kimberlite pipes are in South Africa and Siberia, but there are some in North America, in Australia, and probably also in Brazil, where they may be well hidden under younger sediments.

Figure 1. Model of a Kimberlite pipe (from K.G. Cox, 1978).
The model is based on several South African pipes which have been exposed at various levels by erosion, not only on the one near the town of Kimberley, which gave this formation its name. The model was devised by J.B. Hawthorne of DeBeers Consolidated Mines, Ltd.

   "The diamond pipes serve as a window that gives us a look into the Earth. There is probably no other group of rocks that originated from even remotely as great a depth as have these" (Kennedy and Nordly, 1968).
   The pressure and temperature at a depth of 150 or 200 kilometers are in the right range for carbon to crystallize as diamond. But how did the carbon become concentrated? We cannot reasonably suppose that concentrations of large pieces of pure carbon were formed in the outer mantle by the diffusion through the rock of the dispersed individual carbon atoms.
   Minerals of high purity are usually formed in the Earth by a process that involves the flow of some liquid through cracks and pore spaces in the rock. In some particular circumstance of pressure, temperature or chemical surroundings, a component of such a fluid precipitates, and thus builds up a concentrated deposit in the pore spaces. We then have to suppose that a fluid containing carbon, percolated through rock spaces and precipitated concentrated carbon. Veins of diamond would then be built up in these pore spaces, and a later eruption might bring fragments to the surface. What are the fluids that could be responsible for precipitating and concentrating the carbon?
   The mere existence of the diamonds at these depths proves that unoxidized carbon exists there. The two types of fluids that one may consider for the concentration process would be carbon dioxide and methane, the latter possibly associated with heavier hydrocarbon molecules also. Tiny pore spaces in diamonds have been analyzed and found to contain small amounts of highly compressed gases, among which the carbon-containing ones were both carbon dioxide and methane (Melton and Giardini, 1974). It is clear, therefore, that not only unoxidized carbon, namely the diamond itself, but also methane, can exist down there. Thermodynamic calculations have shown that both these gases are stable in the upper mantle at diamond forming depth, and either could be responsible. The following indications would seem to favor methane. Methane is generally much more abundant in the crust than CO2, and appears to be streaming up from deeper levels. Secondly, of the gases contained in diamonds, nitrogen is by far the most abundant. One has to judge that nitrogen had something to do with the deposition of the diamond.
   It follows that pore spaces in which fluids can flow exist at these depths, and that mineralization processes, leading to great concentrations of certain substances, can be active there, just as they are at shallower levels. Fluid pressures equaling the rock pressures seem to be widespread, at least in the crust and outer mantle, and this is a matter of great significance, both for the chemical processes and for the methods of ascent of fluids to the surface.
   The existence of the kimberlite pipes shows that high concentrations of gas can build up, and have been building up, and these concentrations can explode a hole through 150 kilometers of overlying dense rock. Quite large bubbles of high-pressure gas must have been assembled to do this, and only an inhomogeneous mantle containing volatile-rich materials could be responsible.
   A gas eruption, rather than a volcanic transport to the surface, is required to maintain the diamonds. The stable form of carbon at low pressures is graphite, but if diamonds are cooled sufficiently rapidly as they are brought to lower pressures, they are maintained as unstable but super-cooled crystals. At surface temperatures, they are then effectively stable. We see that the evidence from the diamonds is very simple and clear. Unoxidized carbon can and does exist in the outer mantle. It can be brought up without becoming oxidized; it is associated with a variety of hydrocarbon molecules, both within inclusions in diamond and also in other materials brought up in the eruptions. Volatile-rich regions exist in the mantle, so that high pressure gas bubbles become assembled there that can force their way violently through all the overlying rocks. This clearly shows that the Earth has an unmixed, inhomogeneous mantle, and that there is a high concentration of carbonaceous material in many areas of the globe.
   I am presenting here a selection of eye-witness accounts of major quakes, showing that gases, and in particular combustible gases are frequently in evidence.

The great earthquake series in New Madrid (Mid Mississippi) in 1811 - 1812

   The report by contains the following items:
   On the 16th day of December, 1811, at two o'clock in the morning, the inhabitants of New Madrid were aroused from their slumbers by a deep rumbling noise like many thunders in the distance, accompanied with a violent vibratory or oscillating movement of the earth from the southwest to the northeast, so violent at times that men, women, and children caught hold of the nearest objects to prevent falling to the ground.
   It was dangerous to stay in their dwellings, for fear they might fall and bury them in their ruins; it was dangerous to be out in the open air, for large trees would be breaking off their tops by the violence of the shocks, and continually falling to the earth, or the earth itself opening in dark, yawning chasms, or fissures, and belching forth muddy water, large lumps of blue clay, coal, and sand, and when the violence of the shocks were over, moaned and slept, again gathering power for a more violent commotion.
   On this day twenty-eight distinct shocks were counted, all coming from the southwest and passing to the northeast, while the fissures would run in an opposite direction, or from the northwest to the southeast.
   On a small river called the Pemiseo at that time stood a mill owned by a Mr. Riddle. This river ran a southeast course, and probably was either a tributary of the St. Francis or lost itself in those swamps. This river blew up for a distance of nearly fifty miles, the bed entirely destroyed, the mill swallowed up in the ruins, and an orchard of ten acres of bearing apple trees, also belonging to Mr. Riddle, nearly ruined. The earth, in these explosions, would open in fissures from forty to eighty rods in length and from three to five feet in width; their depth none knew, as no one had strength of nerve sufficient to fathom them, and the sand and earth would slide in or water run in, and soon partially fill them up.
Large forest trees which stood in the track of these chasms would be split from root to branch, the courses of streams changed, the bottoms of lakes be pushed up from beneath and form dry land, dry land blow up, settle down, and form lakes of dark, muddy water.
   One family, in their efforts to reach the highlands by a road they all were well acquainted with, unexpectedly came to the borders of an extensive lake; the land had sunk, and water had flowed over it or gushed up out of the earth and formed a new lake. The opposite shore they felt confident could not be far distant, and they traveled on in tepid water, from twelve to forty inches in depth, of a temperature of 100 degrees, or over blood heat, at times of a warmth to be uncomfortable, for the distance of four or five miles, and reached the highlands in safety.
   On the 8th of February, 1812, the day on which the severest shocks took place, the shocks seemed to go in waves, like the waves of the sea, throwing down brick chimnies level with the ground and two brick dwellings in New Madrid, and yet, with all its desolating effects, but one person was thought to have been lost in these commotions.
The morning after the first shock, as some men were crossing the Mississippi, they saw a black substance floating on the river, in strips four or five rods in breadth by twelve or fourteen rods in length, resembling soot from some immense chimney, or the cinders from some gigantic stove-pipe. It was so thick that the water could not be seen under it. On the Kentucky side of the river there empties into the Mississippi river two small streams, one called the Obine, the other the Forked Deer. Lieutenant Robinson, a recruiting officer in the United States army, visited that part of Kentucky lying between those two rivers in 1812, and states that he found numberless little mounds thrown up in the earth, and where a stick or a broken limb of a tree lay across these mounds they were all burnt in two pieces, which went to prove to the people that these commotions were caused by some internal action of fire.
   About four miles above Paducah, on the Ohio River, on the Illinois side, on a post-oak flat, a large circular basin was formed, more than one hundred feet in diameter, by the sinking of the earth, how deep no one can tell, as the tall stately post-oaks sank below the tops of the tallest trees. The sink filled with water, and continues so to this time. The general appearance of the country where the most violent shocks took place was fearfully changed, and many farms were ruined.
   After reading this and several reports about other earthquakes that are quite similar, I find it very hard to understand how there can be any opposition to the notion that the eruption of gases is connected with earthquakes, and possibly a major cause of them. I know of no way in which an area of land could suddenly sink by tens of feet, except by the release of large amounts of gases whose pressure had previously held open a large total volume of pore-spaces in the underlying rocks.
   The same consideration applies to the creation of the earthquake-related ocean waves called tsunamis. A rapid and very large change in some volume is necessary to set up these waves, and that volumetric change has to be of a magnitude similar to the volume of ocean water that has been displaced to make either the negative or the positive phase of the great wave. Again sinking of an area of ocean floor due to the sudden escape of gases would be a possibility as would the rapid expansion of gases that make their way from the ocean floor to the surface. There are various reports of violent bubbling of areas of the ocean, and even of flames emerging out of the water.
   Another feature of earthquakes that seems incompatible with the theory of shear strain in the rocks reaching breaking point are the deep source earthquakes. Earthquakes are known at depths down to 700 kilometers, and the pressure there is so great that sudden fracture cannot occur. The friction between two masses that slide against each other would be so great that this would far exceed any mechanical breaking strength of any rock. Any movement at such depths would occur only as a gradual adjustment proceeding in step with the driving force that causes the movement. This implied that another process must be going on down there and finding the answer to that may also then explain the features of shallower earthquakes that have so far remained unexplained, but that appear in seismic investigation quite similar to the deep ones.
   We have two recent examples: on June 8, 1994, a very large earthquake registering 8.2 emanated from 600 kilometers below Bolivia. Not far away in time and space, in 1970, there was a powerful deep earthquake in Colombia.
   The southern island arc of Indonesia and its continuation into Burma and the mountains of southern China is a very long belt that shows many features that show themselves along the whole length. Earthquakes make clear that it is related to an underlying structure of very large dimensions. The two other features that follow this same arc all the way are active volcanoes and the commercial production of oil and gas. While the belt was defined by the frequent occurrence of small quakes, it is also the region of the highest frequency of large quakes. In the 75 years between 1897 and 1972, there were ten earthquakes of magnitude eight or larger along this belt. There are no signs of a progressive shift of some land masses against others, and the rock stress situation is surely totally different in the folded mountains of Burma as in the volcanic island arc of Indonesia.
   There are other features of earthquakes that have also to be considered. There are places that are distinctive "earthquake spots." There is a spot in northern Norway where for a long time one could almost be guaranteed to feel an earthquake in any 24 hour period. These were weak earthquakes, not much above the level at which one could feel them, but there was no faultline that was slipping, no accumulation of any deformation of the surface, it just kept shaking in an area that was about 12 kilometers across. A very similar story comes from two places in the United States, one is on the western tip of Flathead Lake in Montana, the other is in Arkansas, near the small town of Enola. Both of those have been active in recent times, and the one in Arkansas is known to have been active some 80 years ago.
   Another earthquake spot is on the north shore of the St. Lawrence River, most interestingly just in a large meteorite impact structure ("astrobleme") called Charlevoix. The large meteorite struck there some 350 million years ago, and detailed evidence of this impact has been obtained. Despite the length of time that has elapsed since then, it seems that even now the area has not settled down and some activity is still clearly centered there. Some earthquakes that can be felt occur there every few days, and microquakes are registered extremely frequently. In this case, the proximity to the major faultline of the St. Lawrence River complicates the discussion somewhat but, nevertheless, the concentration of the seismic activity to the 30 mile diameter impact area is quite evident.
   Such spots clearly need a different explanation from that of plates shearing against each other. Possibly the explanation has to do with gases forcing their way up and causing fractures in the rock to open and shut repeatedly.
   We have investigated in some detail the Arkansas and the Charlevoix spots, and in the course of this discovered that they both contain a most intriguing feature which has shed further light on this type of occurrence. This is the presence of clusters of earth mounds that stand abruptly out of the alluvial plain. From a few feet to 40 feet in height and up to 200 feet or so in the horizontal dimensions, they are composed internally just of the clay and sand of the local alluvium, and no good reason has been offered to account for their origin.
   The association in both areas of these strange mounds with locally concentrated seismic activity cannot reasonably be ascribed to chance. While such mounds do occur elsewhere, dense clusters of them are extremely rare, and an explanation for them is required. One cannot argue that the shaking of the ground of the earthquakes would itself cause what appears to be a substantial extrusion from below.
   A class of a much larger type of feature is known and referred to as "mud volcano." It is also strongly related to earthquake activity. Mud volcanoes are mountains that are in the general shape of a volcano, sometimes but not always with an open hole on top and with steep sides sloping down to the plain below. The sides are made of rock debris, which presumably was ejected at the top as a mixture of such debris with water. Huge fields of mud volcanoes exist in several areas of the globe. The best known ones and the largest are in Azerbaijan on the north slopes of the Caucasus. Large eruptions of individual mud volcanoes are common there and the gases that propel the eruption are usually flammable and become ignited at the time, presumably by electrostatic sparks resulting from the friction of fast moving rock grains. Flames to a height of two kilometers have been photographed from one mud volcano whose orifice measures 120 meters across.
   The gases coming out of mud volcanoes have often quite unusual composition and contain elements that are known to be at a high concentration in the mantle of the earth and at a much lower concentration in the sediments and in the outer crust. They clearly represent a very different chemical environment from that of the sedimentary cover.
   The mounds on the earthquake spots in Enola, Arkansas and in Charlevoix on the St. Lawrence River, can be attributed to the same class of phenomenon as mud volcanoes, only on a much smaller scale.
  Gases that stream up out of cracks during earthquakes are also frequently flammable. In the collection of eyewitness reports, flames are frequently a feature. Also in recent times, the great earthquake in San Francisco in 1906 was accompanied by large fires, and it was said at the time that this was due to the fracture of gas pipes in the ground. That may well have been the case; however flames were also seen on hills nearby that had no gas pipes and also on roads and fields in nearby San Jose. The Armenian earthquake of 1990 showed a line of burnt bushes along a visible faultline.
   Large vertical displacements of areas of land can be understood if a mass of gas had previously held open pore spaces in the rocks below, and thereby raised the ground, and if these pore spaces had suddenly made connections to the surface and rapidly exhausted the gas. Such volumetric changes occurring in a matter of seconds can then account for the large tsunamis and for the flames often seen in earthquakes. As methane appears to be the most common gas in the rocks, it would seem reasonable to expect that methane would be the principal gas responsible, just as it is known in the case of mud volcanoes. The mud volcanoes merely show the locations in which earthquakes and gas eruptions are particularly frequent, and locations in which large amounts of underground mud have been generated by the frequent agitation of ground water in some fine-grained alluvial sediments.

Can the emission of gases be used for precursory information?

   There were two observations before the earthquake at Loma Prieta on October 17, 1989 that seemed to be gas related and are clearly just prior to the earthquake (Reimer, 1990 and Fraser-Smith, 1989). But these observations were made for different purposes, unrelated to earthquake research, and yet they constitute the best earthquake-predictive observations. One was the observation of the amount of helium in a shallow well, which showed a sharp increase a day before the quake (Figure 2). I suppose that this represented an increased flow of gases upwards through the rocks, that had gathered up the helium that had accumulated in the pores.

Figure 2. From Reimer, 1990.
The other observation was that of a low radio frequency noise that is not normally present, also seen just before the quake (Figure 3); I attribute this to the interruption and reconnection of earth currents normally flowing in the groundwater, as these current paths are interrupted and re-connected by the bubbles of insulating gases that stream through the pores of the rock. Would these and other gas-related precursory effects not form the best line of earthquake investigation, to devise the most important of all, a predictive capability?

Figure 3. From Fraser-Smith, 1989.
The eye-witness stories of the past are all ignored or not even known to the present investigators; they are certainly not mentioned much in the modern earthquake literature. See the related documentation describing historical accounts of many large quakes (in "Eye-witness Accounts of Several Major Earthquakes," this Web site).


Cox, K. G. (1978). Kimberlite pipes. Scientific American 238 (4).
Fraser-Smith, A.C. et al. (1989). STAR Laboratory, Stanford University, Stanford, CA 94305.
Kennedy, G.C. and Nordly, B.E. (1968). The genesis of diamond deposits Econ. Geol. 63, 495-503.
Melton, C.E. and Giardini, A.A. (1974). The composition and significance of gas released from natural diamonds from Africa and Brazil. Amer. Mineralogist 59, 775-782.
Reimer, G.M. (1990). Helium increase. Nature, 347, 342.

Eye-witness Accounts of Several Major Earthquakes
Thomas Gold
   To show how common the gas related effects have been in reports of earthquakes of the past, I am giving here a list of such reports. I do not believe that the individual authors had much information about other such reports, and therefore these reports can be taken to be free from suggestive influences.
   I am grateful to my colleague Dr. Steven Soter for his library researches that found the samples given here and many more like these.
  Norcia and Aquila (Italy), 14 January and 2 February 1703
"In Aquila and Norcia, and in other places . . . the earth was here and there observed to split in cracks, from which streamed the evil odors of sulfur and bitumen; and men in Aquila most worthy of trust write that in many places after the earthquake sulfur and fire issued from the opened earth." (Quoted by Galli, 1911)
Lisbon, 1 November 1755
". . . we began to hear a rumbling noise, like that of carriages, which increased to such a degree as to equal the noise of the loudest cannon; and immediately we felt the first shock, which was succeeded by a second and a third; on which, as on the forth, I saw several light flames of fire issuing from the sides of the mountains, resembling that which may be observed on the kindling of coal. . . . I observed from one of the hills called the Fojo, near the beach of Adraga [near Colares], that there issued a great quantity of smoke, very thick, but not very black/ which still increased with the fourth shock, and after continued to issue in a greater or less degree. Just as we heard the subterraneous rumblings, we observed it would burst forth at the Fojo; for the quantity of smoke was always proportional to the subterraneous noise." (Stoqueler, 1756)
Komarom (Hungary), 28 June 1763
   "Ruptures in the soil originated in thousands of places. From almost all of them water and quicksand were emitted together with flames and stinking smoke. . . . The river Danube began to rise . . . and the water appeared to be steaming as though boiling. It had a sulphurous smell. The majority of the ruptures occurred near the river bank and from some of them flames emerged alternately with the sand and smoke. Fertö Lake, 100 km west of Komarom, began to rumble and foam very intensely. . . . Flames as big as a barrel were seen over the river itself. Many horned cattle perished in the terrible stinking vapour that came from the earth. . . . At the bank of another smaller river, the Vag, red-colored flames rushed up from the ruptures, followed by sulphurous waters. . . . At some places the waters that came from the earth were distinctly black. The water of the river Bag appeared to be boiling." (Quoted by Rethly, 1952)
Lima, 30 March 1828
   Water in the bay "hissed as if hot iron was immersed in it," bubbles and dead fish rose to the surface, and the anchor chain of HMS Volage was partially fused while lying in the mud on the bottom. (Bagnold, 1829)
(The anchor chain is reported to be on display in the London Navy Museum.)
   Owens Valley (California), 26 March 1872
"People living near Independence . . . said [that] at every succeeding shock they could plainly see in a hundred places at once, bursting forth from the rifted rocks great sheets of flames apparently thirty or forty feet in length, and which would coil and lap about a moment and then disappear." (San Francisco Chronicle, 2 April 1872)
   "Immediately following the great shock, men whose judgment and veracity is beyond question, while sitting on the ground near the Eclipse mine, saw sheets of flame on the rocky sides of the Inyo mountains but a half a mile distant. These flames, observed in several places, waved to and fro apparently clear of the ground, like vast torches; they continued for only a few minutes." (Inyo Independent, 20 April 1872)
Sonora (Mexico), 3 May 1887
   "Another effect of the earthquake which terrified the frightened inhabitants of these places, was the fire upon all the mountains around the epicenter and even some situated in the territory of Arizona, among others the ridge of San Jose. Some of these, it is said, continued in flames for many days." (Aquilera, 1920)
   Swabia (Southern Germany), 16 November 1911
   The following are from among the many eyewitness accounts quoted by Schmidt and Mack (1913):
"We saw a sea of flames, gas-like and not electrical in nature, shoot up out of the paved market street. The height of the flames I can estimate at 8 to 12 cm; it was like when you pour petroleum or alcohol on the ground and light it."
"I observed very precisely how a bright fire, which had a bluish color, came out of the ground in the meadow. Its height was about 80 cm. . . . The first was present not only in the meadow but also in the whole surroundings of our house."
   "Some people in the streets . . . noticed that for a while before the quake and particularly after it an evil stuffy air made breathing almost impossible."
Rumania, 10 November 1940
   The following are phrases used in eyewitness accounts collected by Demetrescu and Petrescu (1941):
". . . a thick layer like a translucid gas above the surface of the soil . . . irregular gas fires . . . flames in rhythm with the movements of the soil . . . flashes like lightning from the floor to the summit of Mt Tampa . . . flames issuing from rocks, which crumbled, with flashes also issuing from non-wooded mountainsides."
   Sungpan-Pingwu (China), 16, 22, and 23 August 1976
"From March of 1976, various large anomalies were observed over a broad region. . . . At the Wanchia commune of Chungching County, outbursts of natural gas from rock fissures ignited and were difficult to extinguish even by dumping dirt over the fissures. . . . Chu Chieh Cho, of the Provincial Seismological Bureau, related personally seeing a fireball 75 km from the epicenter on the night of 21 July while in the company of three professional seismologists.

The San Francisco Earthquake

   The earthquake that destroyed parts of San Francisco and virtually all of Santa Rosa occurred at 5:12 a.m. on 18 April 1906. It was most intense perhaps a hundred kilometers north of San Francisco. We will here list some excerpts from the numerous reports, all indicating violent gas emission from the ground, gases that contained the poisonous hydrogen sulphide and gases that were frequently flammable. It is the earthquake for with the most detailed reports exist, and which shows every type of phenomenon that we have noted in other cases.

(a) Effects in Air

   An extensive list of noises heard at the time of the shock, compiled from witnesses by Lawson and others (1908), includes the following: From Santa Rosa, "Heard noises in SW; then felt breeze; then felt shock". From Cotati, "Sound as of a strong wind before the shock". From Point Reyes Station, "Heard roar, then felt wind on my face". From Calistoga, "A rushing noise before the shock came". From Pescadero, "Noise as of wind preceded the shock". And from Mount Hamilton, "Sound as of flight of birds simultaneously with shock".
   Other clear evidence for gas is given by a report published on 23 April in the Santa Rosa Democrat-Republican (the first newspaper to appear after the devastation). It said:
   J.B. Doda, who came over from Fort Ross on Monday, reports that the earthquake caused immense cracks in the earth there, from which strong gases are emitted which make men and cattle sick.
   Also, according to Edgar Larkin (1906), who collected a great many accounts, the odour of hydrogen sulphide was noted in the area of Sausalito. He also reported that sulfurous odors were pungent in Napa County during the night of the 17th and 18th before the upheaval, and lasted all day. . . . From many of the letters it is clear that the entire region north and east of San Francisco is saturated with gases of sulfur origin. . . .
   In Santa Rosa, according to Lawson and others (1908), a strong smell of sulphur had been noticed two days before the earthquake by one Charles Kobes. Since during an earthquake eight years previously, "sulfur fumes came up from under his house which almost drove his family from home", the recurrence of this phenomenon on 16 April 1906 caused Kobes to tell his family that there would be another earthquake.

(b) Effects in Water

   Numerous indications of hydrogen sulphide in bodies of water were reported. According to Larkin (1906), "creeks became milky in several places as if gas escaped from the water". Hydrogen sulfide bubbling through water is known to give it a milky appearance. Another report in the San Jose Herald of 2 May 1906 states that in Monterey Bay, on the day of the quake, there were thousands of strange fish floating on the water a few miles offshore, none of which were known to old fishermen on the boat. Similar reports of massive fish kills at times of earthquakes, especially of bottom-dwelling fish, are known from Japan, in some cases also associated with the description of milkiness of the water. Again, hydrogen sulphide, which is highly toxic to fish, seems a likely explanation, and in each case it is bottom dwelling fish which are not normally caught that are the chief victims.

(c) Anomalous Animal Behaviour

   Strange animal behaviour preceding earthquakes is well documented in many parts of the world. Dogs, pigs, horses, cows and many other animals seem to show signs of restlessness or extreme disturbance prior to major earthquakes, and I would attribute this to their ability to smell the outflow of ground gases much more readily than humans and to be altogether much more concerned about smells. In San Francisco the major reports of this nature concerned the behaviour of dogs (Lawson et al., 1908), which are reported to have been howling during the night preceding the earthquake.

(d) Earthquake Lights

   Again, as in many other earthquakes, there are many reports of flames issuing from the ground, either seen close-by or seen as a glow of light in the distance. In fact, while it was reported that the great fire, which was initiated by the earthquake, was in part caused by broken gas mains in the streets of San Francisco, this may not have been the major cause. There are numerous reports of flames seen in neighboring areas where no gas mains existed. Thus, George Madeira, a veteran mining engineer from Healdsburg, reports in the Santa Rosa Republican for 4 April 1910:
   While investigating the natural phenomena of the seismic disturbance of April 18, 1906, I visited the mountain ranch of Mr. and Mrs. Adams, a mile and one-half northeast of Cazadero. They stated that for two night preceding the earthquake they "had seen small streams of lightning running along the ground". Their attention was called to the phenomenon by the incessant barking of their dog.
   Here, evidently some 30 hours before the shock, earthquake lights were reported in what was soon to be the epicentral region.
   During the earthquake itself there were more such accounts, like that of J.E. Houser, and engineer in San Jose, California, quoted by Larkin (1906):
   This report included the following:
   We could see down Alameda Street ablaze with fire, it being of a beautiful rainbow color, but faint. We passed out into the street and met a man who asked, "Did you see the fire in Alameda Street?" An hour later a friend told me that the ground all around was a blaze of fire.

(e) Explosive Noises (Brontides)

   According to George Madeira in a letter written on 5 May 1908, as quoted by Alippi (1911),
   Explosions much resembling the discharge of heavy guns have for the past two years been heard at intervals in the West and Middle Coast range of mountains, particularly in Marin, Sonoma and Mendocino Counties. Heavy detonations and rumblings were heard near the base of Mt. Tamalpais, Marin County, during the winter months and previous to the great earthquake which destroyed San Francisco and Santa Rosa in Sonoma County April 18th, 1906, and have been heard at stated times up to this writing.
   Some of these later explosions evidently accompanied earthquake aftershocks.

(f) Visible Waves

   The phenomenon of slowly rolling waves, like the waves at sea, was reported from many places in the San Francisco earthquake. Lawson and others (1908) list over twenty such accounts distributed geographically from the vicinity of Eureka to Visalia, a distance of more than 600 kilometres. Several of these accounts explicitly compare the ground motion observed to that of waves in the ocean. Similar accounts are also in descriptions of other earthquakes, especially that in Lisbon. These waves were discussed by John Michell (1761), a brilliant scientist of the 18th century. What he presumed was happening was that soft alluvial deposits can be bent and do not fracture as readily as the hard rock beneath. If a great mass of gas suddenly comes from cracks in the rock, it may lift up this carpet and in that case, gravity waves quite similar to the waves in the ocean would be set up.

Can Earthquakes Be Predicted?

   We see that these descriptions make major earthquakes look much like violent eruptions, quite similar to gas eruptions from volcanoes or mud volcanoes. The airborne noises, the flames, the air pollution are all similar, and while most of the intense effects take place at the time of the quake, some of the effects occur as precursors and cannot therefore be ascribed to secondary effects of the mechanical deformation of the ground. It seems very strange that in all the attempts to predict earthquakes, no gas observations are included. Highly accurate measurements of the distortion of the ground represent the main effort, since the current theory has earthquakes resulting from a gradually augmenting stress in the rocks until they reach the breaking strain and the earthquake occurs. It is therefore supposed that one can measure the building up of the stress by the slight deformation prior to a quake. However, as a means to predicting earthquakes, this method has been entirely unsuccessful. The ground does distort on occasions, but not by any unusual amount before an earthquake.
   The evacuation of Haicheng two hours before a devastating quake is an example of a successful prediction, and it was based mainly on gas effects such as a cloud of warmer air and fog developing above the known faultline, strange and nauseating smells and changes in groundwater levels. The same effects have been mentioned in very many of the ancient records.
   Gases can indeed have a lot to do with earthquakes. A large volume of gas entering the crust of the Earth from deeper levels and at a high pressure, will greatly change the mechanical properties of the rock. Pore-spaces will be inflated, and the overburden weight of the rock will be effectively relieved by the pressure of the gas. The great weight of the overburden would normally have resulted in high internal friction, opposing any slippage at all but the shallowest levels. But with gas effectively bearing the overburden, slippage can occur much more easily. Much smaller values of stress in the rock will then be sufficient to cause a quake.
   The absence of high stresses along the San Andreas fault was indeed a surprise to the investigators, when they had a chance to make such measurements in the deep well drilled at Cajon Pass in Southern California. They also failed to find there the extra heat that the known past slippage should have left behind, had it taken place without gas levitation.
   When gas has invaded an area of the crust, it generally shows some emission at the surface that can be observed, and that results in the various effects mentioned. Of course the gases that were in the pore-spaces to start with are pushed up first, before the "new" gas has got to the surface. This brings up smells which cause surprise or consternation among many animals; it brings up more carbon-dioxide and less oxygen than air has normally, and this drives animals out of burrows; it brings up humidity and temperature of the sub-surface and thus frequently makes a fog. This contains more of the heavy CO2 molecule than the average air, and can therefore make a warmer cloud that stays on the ground instead of rising rapidly. Radioactive gases that are normally generated in the ground make a prominent appearance as they are flushed from the ground.
   These signs should be taken to mean that the rock underneath has now suddenly lost much of its strength, and even small stresses will allow it to break. There was no particular build-up of stress prior to the quake, and measurements of this are therefore useless as predictors. The sudden event was the gas invasion that weakened the rock, and it is on this that a prediction method has to be based. During earthquakes and after, a lot more gas escape can usually be observed, and by then the deep source gas may have made its way to the surface. This is often combustible, probably mainly methane as this is in most common gas in deep rocks, and it often catches fire.
   In China, in Japan, in the Soviet Union, much more attention is paid to gas phenomena. Japan even has a "Laboratory of Earthquake Chemistry." The US is far behind in this field, not because it does not have the technology, but just because it took a wrong choice some time ago, and now does not wish to change course. But the citizens of earthquake-prone regions will be more concerned with obtaining a warning than to be party to a scientific controversy. Sub-surface gas observations are simple and comparatively inexpensive, such as changes in groundwater levels in water wells, or changes in gas pressure above a water table. It is high time that California and the Central Mississippi region obtained the knowledge and experience in this field that will be necessary to establish a meaningful prediction service. Instrumentation operated by scientists is one aspect of this; public earthquake education and a reporting network is another, to assure the widest possible coverage for the observation of the many phenomena that may be relevant for predictions. One wonders how many such observations go unreported because their relation to earthquakes is not generally known.


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