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Fault may refer to:

  • Fault (geology), planar rock fractures which show evidence of relative movement
  • Fault (dog), in dog breeding, is an undesirable aspect of structure or appearance that indicates the dog should not be bred
  • Fault (legal), in criminal law, one must determine fault in a crime
  • Fault (technology), an abnormal condition or defect at the component, equipment, or sub-system level which may lead to a failure
  • Fault (tennis), a serve that fails to place a tennis ball in the correct area of play
  • Electrical fault, an unintended electrical connection commonly referred to as a "short circuit"
  • An asymmetric fault or symmetric fault in an electric power system

See also


1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

FAULT (Mid. Eng. faute, through the French, from the popular Latin use of fallere, to fail; the original l of the Latin being replaced in English in the 15th century), a failing, mistake or defect.

In geology, the term is given to a plane of dislocation in a portion of the earth's crust; synonyms used in mining are " trouble," " throw " and " heave "; the German equivalent is Verwerfung, and the French faille. Faults on a small scale are sometimes sharply defined planes,' as if the rocks had been sliced through and fitted together again // p //? / after being shif ted __ 1 I I (fig. r). In such cases, however, the ' - _ harder portions of the I l f" = :-1

?;:? dislocated rocks will i usually be found " slickensided." More frequently some dis turbance has occurred on one or both sides of the fault. Sometimes in a series of strata the beds on the side which has been pushed up are bent down against the fault, while those on the opposite side are bent up (fig. 2). Most commonly FIG. 2. - Section of strata, bent at a line of fault.

the rocks on both sides are considerably broken, jumbled and crumpled, so that the line of fracture is marked by a belt or walllike mass of fragmentary rock, fault-rock, which may be several yards in breadth. Faults are to be distinguished from joints and fissures by the fact that there must have been a movement of the rock on one side of the fault-plane relatively to that on the other side. The trace of a fault-plane at the surface of the earth is a line (or belt of fault-rock), which in geological mapping is often spoken of as a " fault-line " or " line of fault." Fig. 3 ?

FIG. 3. - Plan of simple fault.

represents the plan of a simple fault; quite frequently, however, the main fault subdivides at the extremities into a number of minor faults (fig. 4), or the main fault may be accompanied by FIG. 4. - Plan of a fault splitting into minor faults.

lateral subordinate faults (fig. 5), some varieties of which have been termed flaws or Blatts. " Faultplanes "are sometimes perpendicular to the horizon, but more usually they are inclined at a greater or lesser angle. The angle made by the fault-plane with the vertical is the hade of the ' The fault-plane is not a plane surface in the mathematical sense; it may curve irregularly in more than one direction.

fault (if the angle of inclination were measured from the horizon, as in determining the " dip " of strata, this would be expressed as the " dip of the fault "). In figs. 1 and 2 the faults are hading d `i 'h FIG. 5. - Plan of main fault, with branches.

towards the right of the reader. The amount of dislocation as measured along a fault-plane is the displacement of the fault (for an illustration of these terms see fig. 18, where they are applied to a thrust fault); the vertical displacement is the throw (Fr. rejet); the horizontal displacement, which even with vertical movement must arise in all cases where the faults are not perpendicular to the horizon and the strata are not horizontal, is known as the heave. In fig. 6 the displacement is equal to the throw in the fault A; in the fault B the displacement is more than F IG. 6. - Section of a vertical and inclined fault.

twice as great as in A, while the throw is the same in both; the fault A has no heave, in B it is considerable. The rock on that side of a fault which has dropped relatively to the rock on the other is said to be upon the downthrow side of the fault; conversely, the relatively uplifted portion is the upthrow side. The two fault faces are known as the " hanging-wall " and the " foot-wall." The relationship that exists between the hade and the direction of throw has led to the classification of faults into " normal faults," which hade under the downthrow side, or in other words, those in which the hanging-wall has dropped; and " reversed faults," which hade beneath the upthrow side, that is to say, the foot-wall exhibits a relative sinking. Normal faults are exemplified in figs. I, 2, and 6; in the latter the masses A and B are on the downthrow sides, C is upthrown. Fig. 7 represents a small reversed fault. Normal faults are FIG. 7. - Reversed fault, Liddesdale.

so called because they are more generally prevalent than the other type; they are sometimes designated " drop " or " gravity " faults, but these are misleading expressions and should be discountenanced. Normal faults are regarded as the result of stretching of the crust, hence they have been called " tension faults as distinguished from reversed faults, which are assumed to be due to pressure. It is needful, however, to exercise great caution in accepting this view except in a restricted and localized sense, for there are many instances in which the two forms are intimately associated (see fig. 8), and a whole complex system of faults may be the result of horizontal (tangential) pressure alone or even of direct vertical uplift. It is often tacitly assumed k A FIG. I. - Section of clean-cut fault.

2 07

that most normal and reversed faults are due to simple vertical movements of the fractured crust-blocks; but this is by no means the case. What is actually observed in examining a fault is the apparent direction of motion; but the present position of the dislocated masses is the result of real motion or series of FIG. 8. - Diagram of gently undulating strata cut by a fault, with alternate throw in opposite directions.

motions, which have taken place along the fault-plane at various angles from horizontal to vertical; frequently it can be shown that these movements have been extremely complicated. The striations and " slickensides " on the faces of a fault indicate only the direction of the last movement.

FIG. 9. - Section of strata cut by step faults.

A broad monoclinal fold is sometimes observed to pass into a fault of gradually increasing throw; such a fault is occasionally regarded as pivoted at one end. Again, a faulted mass may be on the downthrow side towards one end, and on the upthrow side towards the other, the movement having taken place about X Q A b Ct 'I - ---X ----- X ' - x ,NflM V z FIG. to. - Trough faults.

an axis approximately normal to the fault-plane, the " pivot " in this case being near the centre. From an example of this kind it is evident that the same fault may at the same time be both " normal " and " reversed " (see fig. 8). When the principal movement along a highly inclined fault-plane has been approxi .1.:' 7 7 ' South FIG. IL - Plan of a strike fault.

mately horizontal, the fault has been variously styled a lateralshift, transcurrent fault, transverse thrust or a heave fault. The horizontal component in faulting movements is more common than is often supposed.

A single normal fault of large throw is sometimes replaced by a series of close parallel faults, each throwing a small amount in the same direction; if these subordinate faults occur within a narrow width of ground they are known as distribution faults; if they are more widely separated they are called step faults (fig. 9). Occasionally two normal faults bade towards one another and intersect, and the rock mass between them has been let down; this is described as a trough fault (fig. 10). A fault running parallel to the strike of bedded rocks is a strike fault; one which runs along the direction of the FIG. 12. - Section across the plan, fig. I I. dip is a dip fault; a so-called diagonal fault takes a direction intermediate between these two directions. Although the effects of these types of fault upon the outcrops of strata differ, there are no intrinsic differences between the faults themselves.

The effect of normal faults upon the outcrop may be thus briefly summarized: - a strike fault that hades with the direction of the dip may cause beds to be cut out at the surface on the b b FIG. 13. - Plan of strata cut by a dip fault.

upthrow side; if it hades against the dip direction it may repeat some of the beds on the upthrow side (figs. 1 i and 12). With dip faults the crop is carried forward (down the dip) on the upthrow side. The perpendicular distance between the crop of the bed (dike or vein) on opposite sides of the fault is the " offset." The offset decreases with increasing angle of dip and increases with increase in the throw of the fault (fig. 13).

FIG. 14. - Plan of strata traversed by a diminishing strike fault.

Faults which run obliquely across the direction of dip, if they hade with the dip of the strata, will produce offset with " gap " between the outcrops; if they hade in the opposite direction to the dip, offset with " overlap " is caused: in the latter case the crop moves forward (down dip) on the denuded upthrow side, in the former it moves backward. The effect of a strike fault of diminishing throw is seen in fig. 14. Faults crossing folded strata cause the outcrops to approach on the upthrow side of a syncline and tend to separate the outcrops of an anticline (figs. 15, 16, 17).

In the majority of cases the upthrown side of a fault has been so reduced by denudation as to leave no sharp upstanding ridge; but examples are known where the upthrown side still Is' exists as a prominent cliff-like face of rock, a "fault-scarp "; familiar instances occur in the Basin ranges of Utah, Nevada, &c., and many smaller examples have been observed in the areas affected by recent earthquakes in Japan, San Francisco and other places. But although there may be no sharp cliff, the effect of faulting upon topographic forms is abundantly evident wherever a harder series of strata has been brought in juxtaposi tion to softer rocks. a r By certain French writers, the upstanding side of a faulted piece of ground is said to have a regard, thus the ° faults of the Jura Mountains have a " regard francais," and a in the same region it has been observed that a in curved faults the convexity is directed the same way as the syncline (S), dislocated by a fault. regard. Occasionally one or more parallel faults have let down an intervening strip of rock, thereby forming " fault valleys " or Graben (Grabensenken); the Great Rift Valley is a striking example. On the other hand, a large area of rock is sometimes lifted up, or surrounded by a system of faults, which have let down the encircling ground; such a fault-block is known also as a horst; a considerable area of Greenland stands up in this manner.

Faults have often an important influence upon water-supply by bringing impervious beds up against pervious ones or vice versa, thus forming underground dams or reservoirs, or allowing water to flow away that would otherwise be conserved. Springs often rise along the outcrop of a fault. In coal and metal mining it is evident from what has already been said that faults must act sometimes beneficially, sometimes the reverse. It is a common occurrence for fault-fissures and fault-rock to appear as valuable mineral lodes through the infilling or impregnation of the spaces and broken ground with mineral ores.

In certain regions which have been subjected to very great crustal disturbance a low hade - sometimes d type of fault is found which possesses a very 60 / A d 60 only a few degrees from the horizontal - \. and, like a reversed fault, hades beneath the upthrown mass; FIG. 17. - Section along the downcast these are termed side of same fault.

thrusts, overthrusts, or overthrust faults (Fr. recouvrements, failles de chevauchement, charriages; Ger. ZTberschiebungen, Uberspriinge, Wechsel, Fallenverwerfungen). Thrusts should not be confused with reversed faults, which have a strong hade. Thrusts play a very important 's.

part in the N.W. highlands of Scotland, the Scandinavian high &c. By the action of thrusts enormous masses of rock have been pushed almost horizontally over underlying rocks, in some cases for several miles. One of the largest of the Scandinavian thrust FIG. 18. - Diagram to illustrate the terminology of faults and thrusts.

F e fav?red dOwnF r '`'.

.

.e ? ' . .. - - ----r  ?

? F F /, lands, the western Alps, the Appalachians, the Belgian coal region, Moine Thrust Plane Si A C - M _ ? ????.

?" .. olne Th P ' '; F S .E.

?? ' Arnaboll Hill  ?,_ .?

Loch Eriboll . ~ 2. ;F Hope u'?'?'v Scale, t inch = 13 6 mile r na lne T hr-at rust l ane FIG. 19. - Section of a very large thrust in the Durness Eriboll district, Scotland.

F d 'a ' $ 60' A 1 s F FIG. 15. - Plan of an anticline (A) and. ' .

A ` 60 u u ` u FIG. 16. - Section along the upcast side of the fault in fig. 15.

60' masses is 1120 m. long, So m. broad, and 5000 ft. thick. In Scotland three grades of thrusts are recognized, maximum, major, and minor thrusts; the last have very generally been truncated by those of greater magnitude. Some of these great thrusts have received distinguishing names, e.g. the 1Vloine thrust (fig. 19) and the Ben More thrust; similarly in the coal basin of Mons and Valenciennes we find the faille de Boussu and the Grande faille du midi. Overturned folds are frequently seen passing into thrusts. Bayley Willis has classified thrusts as (I) Shear thrusts, (2) Break thrusts, (3) Stretch thrusts, and (4) Erosion thrusts.

Dr J. E. Marr (" Notes on the Geology of the English Lake District," Proc. Geol. Assoc., 1900) has described a type of fault which may be regarded as the converse of a thrust fault. If we consider a series of rock masses A, B, C - of which A is the oldest and undermost - undergoing thrusting, say from south to north, should the mass C be prevented from moving forward as rapidly as B, a low-hading fault may form between C and B and the mass C may lag behind; similarly the mass B may lag behind A. Such faults Dr Marr calls "lag faults." A mass of rock suffering thrusting or lagging may yield unequally in its several parts, and those portions tending to travel more rapidly than the adjoining masses in the same sheet may be cut off by fractures. Thus the faster-moving blocks will be separated from the slower ones by faults approximately normal to the plane of movement: these are described as " tear faults." Faults may occur in rocks of all ages; small local dislocations are observable even in glacial deposits, alluvium and loess. A region of faulting may continue to be so through more than one geological period. Little is known of the mechanism of faulting or of the causes that produce it; the majority, of the text-book explanations will not bear scrutiny, and there is room for extended observation and research. The sudden yielding of the strata along a plane of faulting is a familiar cause of earthquakes.

See E. de Margerie and A. Heim, Les Dislocations de l'ecorce terrestre (Zurich, 1888); A. Rothpletz, Geotektonische Probleme (Stuttgart, 1894); B. Willis, " The Mechanics of Appalachian Structure," 13th Ann. Rep. U.S. Geol. Survey (1891-1892, pub. 1893). A prolonged discussion of the subject is given in Economic Geology, Lancaster, Pa., U.S.A., vols. i. and ii. (1906, 1907). (A. GE.; J. A. H.)


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Bible wiki

Up to date as of January 23, 2010

From BibleWiki

Harmful neglect of duty. The "culpa" of Roman law is treated to some extent under the heads of Accident and Bailments, the former dealing with torts arising from lack of care, the latter with the loss of goods or animals through the lack of care or the dishonesty ("dolus") of the keeper.

Fault in Workmanship.

Another important branch of fault or culpa arises where men entrusted with material to work up, or with implements to repair, do their task badly, or disregard the instructions of the owner, or injure thethings entrusted to them. The principles governing this branch are briefly laid down in the Mishnah (B. Ḳ. ix. 3, 4); "If one has given [anything] to mechanics to repair, and they have ruined [it], they must make compensation. If a wagon, a chest, a platform, has been given to a carpenter to repair, and he has ruined it, he is held responsible. And the mason who has undertaken to take down a wall, and in doing so breaks the stones, or does damage, is likewise responsible. [If] he was tearing down on one side, and it fell on another side, he is free from liability; but if [it fell] from his stroke, he is liable. When one gives wool to a dyer and the kettle burns it, the dyer must pay the price of the wool. If he dyes it [so that it looks] ugly, then if the improvement is greater than the outlay, [the owner] pays the amount expended; if the outlay is greater than the improvement, he gives the workman the value of the improvement. [If he gives him wool] to dye black, and he dyes it red, or red and he dyes it black, R. Meïr says he [the dyer] gives him the price of the wool, [keeping the dyed wool]. R. Judah [whose opinion prevails] says: If the improvement is greater than the outlay, he [the owner] pays him [the dyer] the outlay; if the outlay is greater than the improvement, he gives the worth of the latter."

The Gemara ad locum (B. Ḳ. 98b-102a), commenting on these two sections, discusses mainly the question whether the workman, by making a change in the object on which he is working, acquires title thereto, and how this would affect the measure of his liability; but the Halakah is against the view of a change of title.

Maimonides, in "Yad," Sekirut, x. 4, and Ḥobel u-Mazziḳ, vi. 11, states the law almost in the words of the Mishnah; adding to it for greater clearness a few words from the Talmud; "Whether the owner has given to the mechanic the wagon, etc., to put a nail in [that is, to make a slight repair], or has given him the timber to make the wagon, etc., the mechanic, if he breaks the wagon, etc., must pay the value of the wagon [of course deducting his wages and outlays]." To the case of the dyer, Maimonides adds: "Or if he gives timber to a mechanic to make a chair, and he makes a bad one, or makes a bench, he must pay for a good chair. And as the workman does not acquire the ownership by change in the material, the employer can not say, 'Let him pay me for my timber or my wool'; nor can the mechanic clear himself by offering to pay the price of the material."

Fault by Lack of Skill.

A baraita in the discussions on B. Ḳ. ix. 3 (99b) takes up the workman's liability for lack of skill: "If one gives wheat out to grind, and [the miller] does not bold it, but turns it into coarse meal and bran; flour to a baker, and he makes it into flat loaves; a beast to the slaughterer, and he makes a carcass of it [kills it in an unlawful way], the workman is liable, because he is a taker of hire." Maimonides quotes this (ib. x. 5), and, following the reasoning of the Talmud, adds: "Hence, if the slaughterer was an expert and slaughtered without reward, he is free from liability; but if not an expert, though he did it for nothing, he is liable. Thus, if I show a coin to a banker who is well posted, and he tells me it is good, whereas it is bad, but charges me nothing, he is not liable for the loss. But if he is not posted he is liable, though he acted for nothing; for I ought to be able to rely on a banker's opinion. And so in like matters." There is in modern law a similar rule, that a quack is liable for mistakes in medical treatment, where a regular physician would not be liable.

In referring to the mason who does harm while taking down a wall ("Yad," Hobel, vi. 11), Maimonides couples with him the Smith who starts a fire by sparks from his hammer; for a human being, he says, is always "forewarned," whether he acts wilfully or unwittingly, asleep or awake (see Accident).

Another rule connected with fault on the part of workmen entrusted with material or goods is thus stated in the Mishnah (B. M. vi. 6): "All mechanics are keepers for hire [and liable for loss or damage as such]; but all of them, when they say, 'Take thy goods and give me my money,' become gratuitous keepers. When [the owner] says, 'Keep this for me [to-day] and I will keep for you to-morrow,' he is a hired keeper. [If the owner says], 'Keep for me,' and he answers, 'It lies with me,' [he becomes] a gratuitous keeper." R. Huna, in the Talmud on this section, adds: "If he says, 'It lies before thee,' the mechanic is no longer even a gratuitous keeper" (B, M. 81b). And Maimonides ("Yad," Sekirut, ch. x.) gives these propositions as the Halakah.

The following case, however, of acting outside the line of strict law may be mentioned in this connection, though it is not noted by the codifiers: It happened to Rabba bar bar Ḥanah (others read "bar Rab Hunah") that the porters broke a cask of wine belonging to him. Then he took away their clothes in compensation. They went to Rab and complained. Whereupon he said, "Rabba, return them their clothes." The latter asked, "Is this the law?" Rab said, "Yes; as it is said, 'That thou mayest walk in the way of the good ones' (Prov 2:20)." He returned their clothes. Then the porters said to Rab, "We are poor and labor the whole day, and now we are hungry and have nothing." Rab then said to Rabba, "Go and pay them their wages." Rabba asked again, "Is this the law?" Rab replied, "Yes; as it is said, 'And keep the paths of the righteous'" (B. M. 83a).

As to a pawning of the finished commodity, and the pawnee's liability for a loss, see Pledges.

This entry includes text from the Jewish Encyclopedia, 1906.
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