1891 earthquake, earthquake, earthquake risk, fault-lines, faults, Fukushima, historic earthquake, Japan, land-shift, Monju nuclear reactor, nuclear energy, nuclear hubris, nuclear power, subsidence, Tsuruga reactor
It seemed time to take a look at the widespread and bizarre geological impacts of Japan’s largest on and offshore earthquakes, since Japanese Atomic Power Co. (JAPC) and earthquake experts have been arguing about whether or not some faults under the Tsuruga Nuclear Power Station are active, seemingly oblivious to the faults that run next to it. There is also debate about if a potential quake is a 7.2 or 7.4. Faults are also near the neighboring and more dangerous Monju Fast Breeder, (plus there is Mihama not too far away on the same peninsula). Some of the faults are not even on the government maps. More fault-lines appear on the JAPC maps than government maps for this area. JAPC recognizes the faults but apparently does not think them a problem. The government of Japan doesn’t even list some faults.
For impacts we set aside the Fukushima Daiichi nuclear power station, which continues to leak radionuclides into the Pacific. This is an ongoing nuclear disaster. Instead the focus is on the oft-forgotten weird geological events, which could lead to another nuclear disaster. Meanwhile, the Japanese nuclear industry appears to think that only an “active” fault directly under a reactor matters, with typical hubris.
The largest earthquake with the epicentre on land in Japan is believed to be the 1891 Mino-Owari earthquake (M 8.0). The largest earthquake to impact it from offshore is the 2011 Great Tohoku Earthquake (M 9.0 offshore), more popularly called “Fukushima” in the English-speaking world.
“The 1891 Mino-Owari earthquake (美濃尾張地震 Mino-Owari Jishin?) struck the former Japanese provinces of Mino and Owari in the Nōbi Plain in the early morning of October 28 with a surface wave magnitude of 8.0. The event, also referred to as the Nōbi Earthquake (濃尾地震 Nōbi Jishin?) or the Great Nōbi Earthquake (濃尾大地震 Nōbi Daijishin?), is the largest known inland earthquake to have occurred in the Japanese archipelago“. http://en.wikipedia.org/wiki/1891_Mino-Owari_earthquake
About the 1891 earthquake, said to be M 8.0, Davison (1905) says:
“As in all disastrous earthquakes, the surface of the ground was scarred and rent by the shock. From the hillsides great landslips descended, filling the valleys with débris; and slopes which were formerly green with forest, after the earthquake looked as if they had been painted yellowish-white. Innumerable fissures cut up the plains, the general appearance of the ground, according to Professor Milne, being ‘as if gigantic ploughs, each cutting a trench from 3 to 12 feet deep, had been dragged up and down the river-banks’ But by far the most remarkable feature of the earthquake was a great rent or fault, which, unlike the fissures just referred to, pursued its course regardless of valley, plain, or mountain. Although at first sight quite insignificant in many places, and some time hardly visible to the untrained eye, Professor Koto has succeeded in tracing this fault along the surface for a distance of forty miles, and he gives good reasons for believing that its total length must be not less than seventy miles“. (Davison, 1905)
Fig. 47.—The Fault-scarp at Midori. (Koto), in DAVISON (1905)
Neodani fault, by Tomomarusan, CC-BY-SA-3.0
(Note the size of the people vs. the fault scarp.) http://en.wikipedia.org/wiki/1891_Mino-Owari_earthquake
These maps show that the impact was widespread for both the Tohoku (Fukushima) and the 1891 earthquakes.
Fig. 41.—Sketch-Map of Disturbed Area and Isoseismal Lines (Masato), in Davison 1905, with red arrow indicating area of Tsuruga, Monju Fast Breeder and Mihama nuclear power stations. They are to the left side of the bay. The bay indicated by the arrow has about 15 reactors in all. There are as many or more fault-lines in this area, as reactors. This is not to suggest that this particular fault would impact the reactors, since it ruptured recently, but rather to make the point of widespread intensity of large earthquakes.
Seismic intensity map of M9.0 Tohoku earthquake(Sendai earthquake). Note that since it was an offshore quake, it was not M9.0 onshore.
March 11, 2011, by Pekachu, CC-BY-SA-3.0
“The 2011 earthquake of the Pacific coast of Tōhoku … was a magnitude 9.0 (Mw) undersea megathrust earthquake off the coast of Japan that occurred at 14:46 JST (05:46 UTC) on Friday 11 March 2011, with the epicentre approximately 70 kilometres (43 mi) east of the Oshika Peninsula of Tōhoku and the hypocenter at an underwater depth of approximately 30 km (19 mi)” http://en.wikipedia.org/wiki/2011_Tōhoku_earthquake_and_tsunami
From Davison (1905): THE JAPANESE EARTHQUAKE OF OCTOBER 28TH, 1891.
“The part of Japan over which the earthquake was sensibly felt is shown in Fig. 41. The small black area in the centre is that in which the shock was most severe and the principal damage to life and property occurred. The other bands, more or less darkly shaded according to the greater or less intensity of the shock, will be referred to afterwards. …as the greater part of it lies within the two provinces of Mino and Owari, the earthquake is generally known among the Japanese themselves as the Mino-Owari earthquake of 1891.
… The “most severely shaken” district, that in which the destruction of buildings and engineering works was nearly complete, contains an area of 4,286 square miles, or about two-thirds that of Yorkshire. This is indicated on the map by the black portion. Outside this lies the “very severely shaken” district, 17,325 square miles in area, extending from Kobe on the west to Shizuoka on the east, in which ordinary buildings were destroyed, walls fractured, embankments and roads damaged, and bridges broken down. The third or “severely shaken” district contains 20,183 square miles; and in this some walls were cracked, pendulum clocks stopped, and furniture, crockery, etc., overthrown. Tokio and Yokohama lie just within this area. In the fourth region the shock was “weak,” the motion being distinctly felt, but not causing people to run out-of-doors; and in the fifth it was “slight,” or just sufficient to be felt. These two regions together include an area of 51,976 square miles.
Thus, the land area disturbed amounts altogether to 93,770 square miles—i.e., to a little more than the area of Great Britain. According to Professor Omori, the mean radius of propagation was about 323 miles, and the total disturbed area must therefore have been about 330,000 square miles, or nearly four times the area of Great Britain. Considering the extraordinary intensity of the shock in the central district, this can hardly be regarded as an over-estimate.
Next to buildings, the embankments which border the rivers and canals suffered the most serious damage, no less than 317 miles of such works having to be repaired. Railway-lines were twisted or bent in many places, the total length demolished being more than ten miles.
…When the line crossed a small depression in the general level of the plain, the whole of the track was bowed, as if the ground were permanently compressed at such places. “Effects of compression,” says Professor Milne, “were most marked on some of the embankments, which gradually raise the line to the level of the bridges. On some of these, the track was bent in and out until it resembled a serpent wriggling up a slope…. Close to the bridges the embankments had generally disappeared, and the rails and sleepers were hanging in the air in huge catenaries.”
“The isoseismal lines shown in Fig. 41 are not to be regarded as drawn with great accuracy; for there is no marked separation between the tests corresponding to the different degrees of the scale of intensity. The seismographs at Gifu and Nagoya  were thrown down within the first few seconds, and failed to record the principal motion. But a great number of well-formed stone lanterns and tombstones were overturned, and, from the dimensions of these, Professor Omori calculated the maximum horizontal acceleration necessary for overturning them at fifty-nine places within the meizoseismal area. At five of these it exceeded 4000 millimetres per second per second, an acceleration equal to about five-twelfths of that due to gravity“. These calculations by Davison are almost exactly the same as a USGS risk map of Japan, for the area and including the 15 reactors on that bay and more:
Continuing with Davison (1905):
…. “In the meizoseismal area, many persons saw waves crossing the surface of the ground. At Akasaka, according to one witness, the waves came down the streets in lines, their height being perhaps one foot, and their length between ten and thirty feet. To the north of the same area, we are told that “the shoreline rose and fell, and with this rising and falling the waters receded and advanced.” Even at Tokio, which is about 175 miles from the epicentre, the tilting of the ground was very noticeable. After watching his seismographs for about two minutes, Professor Milne next observed the water in an adjoining tank, 80 feet long and 28 feet wide, with nearly vertical sides. “At the time it was holding about 17 feet of water, which was running across its breadth, rising first on one side and then on the other to a height of about two feet.” Still clearer is the evidence of the seismographs in the same city. Instead of a number of irregular waves, all the records show a series of clean-cut curves. The heavy masses in the horizontal pendulums were tilted instead of remaining as steady points. They were not simply swinging, for the period of the undulations differed from that of the seismograph when set swinging, and also varied in successive undulations. It was ascertained afterwards, by measurement with a level, that to produce these deflections, the seismograph must have been tilted through an angle of about one-third of a degree….
The general character of the fault-scarp changes with the surface features. On flat ground, where the throw is small, it cuts up the soft earth into enormous clods, or makes a rounded ridge from one to two feet high, so that it resembles, more than anything else,  the pathway of a gigantic mole (Fig. 46). When the throw is considerable—and in one place it reaches from 18 to 20 feet—the fault-scarp forms a terrace, which from a distance has the appearance of a railway embankment (Fig. 47). Or, again, where the rent traverses a mountain ridge or a spur of hills, “it caused extensive landslips, one side of it descending considerably in level, carrying the forest with it, but with the trees complicatedly interlocked or prostrate on the ground.”
Fig. 48.—Displacement of Field Divisions by the Fault near Nishi-Katabira. (Koto.)
At its southern end, the fault was seen for the first time crossing a field near the village of Katabira. The field was broken into clods of earth, and swollen up to a height of 5½ yards, while a great landslip had descended into it from an adjoining hill. A little farther to the north-west, the ground was sharply cut by the fault, the north-east side having slightly subsided and at the same time been shifted horizontally through a distance of 3¼ to 4 feet to the north-west Adjoining fields were formerly separated by straight mounds or ridges running north and south and east and west, and these mounds were cut through by the fault and displaced, as shown in Fig. 48. From this point the fault runs in a general north-westerly direction, the north-east side being always slightly lowered with respect to the other and shifted to the north-west. Near Seki it takes a more westerly direction, and continues so to a short distance east of Takatomi, where the north side is lowered by five feet, and moved about 1¼ feet to the west. At the north end of Takatomi, a village in which every house was levelled with the ground, the fault is double, and the continuous lowering towards the north has converted a once level field into sloping ground. At this point, the small river Toba, flowing south, is partially blocked by the fault-scarp, and an area of about three-quarters of a square mile, on which two villages stand, was converted into a deep swamp (Fig. 49), so that, as the earthquake occurred at the time of the rice-harvest, the farmers were obliged to cut the grain from boats. After passing Takatomi, the fault again turns to the west-north-west, but, the throw being small, it resembles here the track of an enormous  mole. At Uméhara it crosses a garden between two persimmon trees, appearing on the hard face of the ground as a mere line; but the trees, which were before in an east-and-west line, now stand in one running north and south, without being in the least affected by the movement (Fig. 50). From here to Kimbara, where the fault enters the Neo valley, the north side is always depressed and shifted westwards by about 6½ feet.
EFFECT OF THE EARTHQUAKE ON THE SEISMIC ACTIVITY OF THE ADJOINING DISTRICTS.
So great and sudden a displacement as occurred along the fault-scarp could hardly take place without affecting the stability of adjoining regions of the earth’s crust, and we should naturally expect to find a distinct change in their seismic activity shortly after October 28th. In Fig. 59 two such regions are shown, bounded by the straight dotted lines. The district in which the principal earthquake and its after-shocks originated is enclosed within the undulating dotted lines. The continuous lines inside all three districts are the curves corresponding to 10 and 5 epicentres for the years 1885-92. Not far from the axes of the outer groups of curves there are probably transverse faults, approximately parallel to the great fault-scarp and the main branch of the meizoseismal band, and distant from them about 45 and 55 miles respectively….
ORIGIN OF THE EARTHQUAKE.
The last severe earthquake in the Mino-Owari plain occurred in 1859, so that for more than thirty years there had been but little relief to the gradually increasing stresses. Now, the distribution of stress must have been far from uniform throughout the fault-system, and also the resistance to displacement far from proportional to the stresses at different places. At certain points, therefore, the effective stress would be greater than elsewhere, and it would be at these points that fault-slips would first occur. Such slips tend to remove the inequalities in effective stress. Thus, the function of the slight shocks of 1890 and 1891 was, briefly, to equalise the effective stress over the whole fault-system, and so to clear the way for one or more great slips throughout its entire length“. More details and images here: http://www.gutenberg.org/files/25062/25062-h/25062-h.htm#CHAPTER_VII (A Study of Recent Earthquakes by Charles Davison, Sc.D., F.G.S., London and Newcastle-on-Tyne: The Walter Scott Publishing Co, Ltd., 1905)
Little Discussed Bizarre Geological Facts re the March 2011 Great Tohoku (Fukushima) Earthquake
“Portions of northeastern Japan shifted by as much as 2.4 m (7.9 ft) closer to North America, making some sections of Japan’s landmass wider than before. Those areas of Japan closest to the epicenter experienced the largest shifts. A 400 km (250 mi) stretch of coastline dropped vertically by 0.6 m (2.0 ft), allowing the tsunami to travel farther and faster onto land. One early estimate suggested that the Pacific plate may have moved westward by up to 20 m (66 ft), and another early estimate put the amount of slippage at as much as 40 m (130 ft). On 6 April the Japanese coast guard said that the quake shifted the seabed near the epicenter 24 meters (79 ft) and elevated the seabed off the coast of Miyagi prefecture by 3 meters. A report by the Japan Agency for Marine-Earth Science and Technology, published in Science on 2 December 2011, concluded that the seabed in the area between the epicenter and the Japan Trench moved 50 meters east-southeast and rose about 7 meters as a result of the quake. The report also stated that the quake had caused several major landslides on the seabed in the affected area.
“Soil liquefaction was evident in areas of reclaimed land around Tokyo, particularly in Urayasu, Chiba City, Funabashi, Narashino (all in Chiba Prefecture) and in the Koto, Edogawa, Minato, Chūō, and Ōta Wards of Tokyo. Approximately 30 homes or buildings were destroyed and 1,046 other buildings were damaged to varying degrees. Nearby Haneda Airport, built mostly on reclaimed land, was not damaged. Odaiba also experienced liquefaction, but damage was minimal.
Shinmoedake, a volcano in Kyushu, erupted three days after the earthquake. The volcano had previously erupted in January 2011; it is not known if the later eruption was linked to the earthquake. In Antarctica, the seismic waves from the earthquake were reported to have caused the Whillans Ice Stream to slip by about 0.5 m (1.6 ft).”
Map of seismic intensity observations resulting from main shock
[March 11, 2011, by Pekachu, CC-BY-SA-3.0]
“The Earth’s axis shifted by estimates of between 10 cm (4 in) and 25 cm (10 in). This deviation led to a number of small planetary changes, including the length of a day, the tilt of the Earth, and the Chandler wobble. The speed of the Earth’s rotation increased, shortening the day by 1.8 microseconds due to the redistribution of Earth’s mass. The axial shift was caused by the redistribution of mass on the Earth’s surface, which changed the planet’s moment of inertia. Because of conservation of angular momentum, such changes of inertia result in small changes to the Earth’s rate of rotation. These are expected changes for an earthquake of this magnitude. The earthquake also generated sound waves detected by the GOCE satellite, which thus serendipitously became the first seismograph in orbit.
“The first sign international researchers had that the earthquake caused such a dramatic change in the Earth’s rotation came from the United States Geological Survey which monitors Global Positioning Satellite stations across the world. The Survey team had several GPS monitors located near the scene of the earthquake. The GPS station located nearest the epicenter moved almost 4 m (13 ft). This motivated government researchers to look into other ways the earthquake may have had large scale effects on the planet. Scientists at NASA’s Jet Propulsion Laboratory did some calculations and determined that the Earth’s rotation was changed by the earthquake to the point where the days are now 1.8 microseconds shorter.
Dr. Richard Gross, one of the head researchers working for NASA, explained that the way the Earth rotates is not very smooth, like an old car wobbling on its axle. The earthquake’s effect was as if a person took a hammer and whacked the car’s axle, causing it to shift and the car to drive differently. The powerful earthquake hit the Earth’s axle, causing it to spin in a slightly different way.” http://en.wikipedia.org/wiki/2011_Tōhoku_earthquake_and_tsunami
IT EVEN CAUSED SUBSIDENCE AT VOLCANOS 90-120 MILES AWAY (150-200 KM)
According to their abstract, researchers examined “data from satellite radar and the Global Positioning System to show that volcanic regions, located between 150 and 200 km from the rupture area6, experienced subsidence coincident with the Tohoku earthquake. The volcanic regions subsided by 5–15 cm, forming elliptical depressions with horizontal dimensions of up to 15–20 km.” See: “Volcanic subsidence triggered by the 2011 Tohoku earthquake in Japan“, by Youichiro Takada and Yo Fukushima, Nature Geoscience 6, 637–641 (2013)