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when facing the strike direction, or that the dip direction should be 90° clockwise of the strike direction. However, in the UK, the right-hand rule has sometimes been specified so that the dip direction is instead counterclockwise from the strike. Some geologists prefer to use whichever strike direction is less than 180°. Others prefer to use the "dip-direction, dip" (DDD) convention instead of using the strike direction. Strike and dip are generally written as 'strike/dip' or 'dip direction,dip', with the degree symbol typically omitted. The general alphabetical dip direction (N, SE, etc) can be added to reduce ambiguity. For a feature with a dip of 45° and a dip direction of 75°, the strike and dip can be written as 345/45 NE, 165/45 NE, or 075,45. The compass quadrant direction for the strike can also be used in place of the azimuth, written as S15E or N15W.
428:, strike and dip can be represented by a T symbol with a number next to it. The longer line represents strike, and is in the same orientation as the strike angle. Dip is represented by the shorter line, which is perpendicular to the strike line in the downhill direction. The number gives the dip angle, in degrees, below horizontal, and often does not have the degree symbol. Vertical and horizontal features are not marked with numbers, and instead use their own symbols. Beds dipping vertically have the dip line on both sides of the strike, and horizontal bedding is denoted by a cross within a circle.
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There are a few conventions geologists use when measuring a feature's azimuth. When using the strike, two directions can be measured at 180° apart, at either clockwise or counterclockwise of north. One common convention is to use the "right-hand rule" (RHR) where the plane dips down towards the right
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Dip is the inclination of a given feature, and is measured from the steepest angle of descent of a tilted bed or feature relative to a horizontal plane. True dip is always perpendicular to the strike. It is written as a number (between 0° and 90°) indicating the angle in degrees below horizontal. It
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While true dip is measured perpendicular to the strike, apparent dip refers to an observed dip which is not perpendicular to the strike line. This can be seen in outcroppings or cross-sections which do not run parallel to the dip direction. Apparent dip is always shallower than the true dip. If the
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Strike and dip are measured using a compass and a clinometer. A compass is used to measure the feature's strike by holding the compass horizontally against the feature. A clinometer measures the features dip by recording the inclination perpendicular to the strike. These can be done separately, or
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instead. Plunge, or angle of plunge, is the inclination of the feature measured downward relative to horizontal. Trend is the feature's azimuth, measured in the direction of plunge. A horizontal line would have a plunge of 0°, and a vertical line would have a plunge of 90°. A linear feature which
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A feature's orientation can also be represented by its dip direction. Rather than the azimuth of a horizontal line on the plane, the azimuth of the steepest line on the plane is used. The direction of dip can be visualized as the direction water would flow if poured onto a plane.
491:. A compass is used to measure the azimuth of the strike, and the clinometer measures inclination of the dip. Dr. E. Clar first described the modern compass-clinometer in 1954, and some continue to be referred to as Clar compasses. Compasses in use today include the
228:(compass direction) of the strike line. This can be represented by either a quadrant compass bearing (such as N25°E), or as a single three-digit number in terms of the angle from true north (for example, N25°E would simply become 025 or 025°).
524:, and has arms radially attached which can detect the microresistivity of the rock. By recording the times at which the rock's properties change across each of the sensors, the strike and dip of subsurface features can be worked out.
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When measuring or describing the attitude of an inclined feature, two quantities are needed. The angle the slope descends, or dip, and the direction of descent, which can be represented by strike or dip direction.
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on a horizontal plane. Z: strike line of the red plane, σ: strike angle, F: dip direction, φ: dip angle. The angle of the intersection with the green plane is the red plane's apparent dip in the northward direction
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can be accompanied with the rough direction of dip (N, SE, etc) to avoid ambiguity. The direction can sometimes be omitted, as long as the convention used (such as right-hand rule) is known.
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The measurement of a linear feature's orientation is similar to strike and dip, though the terminology differs because "strike" and "dip" are reserved for planes. Linear features use
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of an area. Strike and dip information recorded on a map can be used to reconstruct various structures, determine the orientation of subsurface features, or detect the presence of
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162:, etc. Observations about a structure's orientation can lead to inferences about certain parts of an area's history, such as movement, deformation, or
224:, fault, or other planar feature, is a line representing the intersection of that feature with a horizontal plane. The strike of the feature is the
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Cross-section of an anticline with a dike cutting through it, with the a map view of the surface expression showing the strike and dip of each bed
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where δ is the true dip, α is the apparent dip, and β is the angle between the strike direction and the apparent dip direction, all in degrees.
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99:) measured downward from horizontal. They are used together to measure and document a structure's characteristics for study or for use on a
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386:(or pitch). Unlike plunge, which is the feature's azimuth, the rake is the angle measured within the plane from the strike line.
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A feature that is completely flat will have the same dip value over the entire surface. The dip of a curved feature, such as an
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735:"How to calculate an apparent dip from a real dip (and viceversa) using orthographic projection and trigonometry"
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When studying subsurface features, a dipmeter can be used. A dipmeter is a tool that is lowered into a
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Weng Y.-H., Sun F.-S. & Grigsby J.D. (2012). "GeoTools: An android phone application in geology".
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functionality of such devices, this allows readings to be recorded and later downloaded onto a map.
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A feature's apparent dip is shown when the exposed face is not aligned to the dip direction
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Strike is a representation of the orientation of a tilted feature. The strike line of a
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780:"Ein zweikreisiger Geologen- und Bergmannskompaß zur Messung von Flächen und Linearen"
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which can make strike and dip measurements are also available, including apps such as
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strike is known, the apparent dip or true dip can be calculated using trigonometry:
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For the angle made with the horizontal by the Earth's magnetic field lines, see
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678:(8 ed.). Upper Saddle River, N.J.: Pearson / Prentice Hall. p. 308.
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Any planar feature can be described by strike and dip, including
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300:{\displaystyle \alpha =\arctan(\sin \beta \times \tan \delta )}
757:"Digital Cartographic Standard for Geologic Map Symbolization"
479:, used commonly by geologists for strike and dip measurements
356:{\displaystyle \delta =\arctan(\tan \alpha \div \sin \beta )}
591:
Physical
Geology, First University of Saskatchewan Edition
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Interpretation of strike and dip is a part of creating a
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of an imagined horizontal line across the plane, and its
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to provide orientation measurements. Combined with the
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103:. A feature's orientation can also be represented by
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Example of strike and dip on tilted sedimentary beds
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720:Geological Structures and Maps - A Practical Guide
509:. These apps can make use of the phone's internal
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483:Strike and dip are measured in the field using a
417:Some common map symbols, including strike and dip
68:is a measurement convention used to describe the
672:Tarbuck, Edward J; Lutgens, Frederick K (2005).
382:lies within a plane can also be measured by its
625:Geological Structures: A Practical Introduction
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784:Verhandlungen der Geologischen Bundesanstalt
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675:Earth: An Introduction to Physical Geology
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843:. Kansas State University. 2017-03-24.
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619:Waldron, John; Snyder, Morgan (2020).
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761:FGDC Geological Data Subcommittee
27:Orientation of a geologic feature
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847:from the original on 2021-04-25.
745:from the original on 2021-06-11.
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567:from the original on 2021-12-29.
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115:together using a tool such as a
95:is the angle of inclination (or
868:. New York: J. Wiley and Sons.
587:"Measuring Geological Features"
178:Strike and dip shown alongside
698:New International Encyclopedia
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841:KGS - Geological Log Analysis
862:Compton, Robert R. (1985).
823:10.1016/j.cageo.2012.02.027
803:Computers & Geosciences
723:(3 ed.). pp. 2–6.
621:"Orientation of Structures"
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557:"Measuring dip and strike"
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1241:Thick-skinned deformation
717:Lisle, Richard J (2004).
638:Lahee, Federic H (1961).
627:. Open Education Alberta.
1246:Thin-skinned deformation
1022:Stereographic projection
644:(1 ed.). New York:
585:Panchuck, Karla (2018).
1012:Orthographic projection
995:Measurement conventions
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1071:Convergent boundary
971:Strain partitioning
956:Overburden pressure
946:Mohr–Coulomb theory
837:"The Dipmeter Tool"
815:2012CG.....44...24W
477:Brunton Geo Transit
180:cardinal directions
128:sedimentary bedding
1600:Structural geology
1510:Kinematic analysis
1166:Mountain formation
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1046:Accretionary wedge
922:Structural geology
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1279:Exfoliation joint
1269:Columnar jointing
929:Underlying theory
875:978-0-471-82902-7
164:tectonic activity
70:plane orientation
49:Tilted layers of
16:(Redirected from
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1317:Cataclastic rock
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121:Silva compass
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39:
33:
19:
18:Dip (geology)
1347:Thrust fault
1036:Large-scale
1026:
1007:Inclinometer
981:Stress field
864:
840:
831:
806:
802:
796:
787:
783:
773:
760:
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738:
729:
719:
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364:
251:
247:
236:Apparent dip
230:
219:
199:
195:
186:
125:
113:
108:
104:
101:geologic map
92:
84:
65:
59:
32:Magnetic dip
1528:Paleostress
1414:Slickenside
1389:Crenulation
1342:Fault trace
1337:Fault scarp
1327:Disturbance
1312:Cataclasite
1201:Rift valley
1121:Half-graben
1091:Fault block
1076:Décollement
646:McGraw-Hill
487:and with a
452:Conventions
447:Measurement
1594:Categories
1556:Pure shear
1543:Shear zone
1500:Competence
1384:Compaction
1261:Fracturing
1056:Autochthon
1051:Allochthon
528:References
489:clinometer
146:, igneous
1492:Boudinage
1472:Monocline
1467:Homocline
1447:Anticline
1429:Tectonite
1419:Stylolite
1394:Fissility
1371:lineation
1367:Foliation
1231:Syneclise
1176:Obduction
1146:Inversion
1038:tectonics
884:301031779
809:: 24–30.
437:anticline
348:β
345:
339:÷
336:α
333:
324:
315:δ
292:δ
289:
283:×
280:β
277:
268:
259:α
210:fold axis
202:anticline
156:foliation
132:fractures
1579:Category
1551:Mylonite
1482:Vergence
1477:Syncline
1379:Cleavage
1304:Faulting
845:Archived
743:Archived
565:Archived
522:borehole
507:GeoTools
495:and the
441:syncline
206:syncline
170:Elements
74:attitude
1452:Chevron
1439:Folding
1284:Fissure
1236:Terrane
1181:Orogeny
1161:Mélange
1096:Fenster
986:Tension
811:Bibcode
701:. 1905.
695:"Dip".
485:compass
443:folds.
226:azimuth
144:cuestas
89:azimuth
87:is the
62:geology
1226:Suture
1211:Saddle
1151:Klippe
1116:Graben
976:Stress
966:Strain
882:
872:
693:
652:
379:plunge
321:arctan
265:arctan
216:Strike
160:fabric
140:joints
136:faults
85:strike
78:planar
55:Cyprus
1561:Shear
1289:Joint
1171:Nappe
1131:Horst
1126:Horse
461:Tools
375:trend
152:sills
148:dikes
119:or a
76:of a
51:chalk
1462:Dome
1369:and
1294:Vein
1274:Dike
1206:Rift
1017:Rake
880:OCLC
870:ISBN
765:USGS
650:ISBN
384:rake
377:and
158:and
150:and
819:doi
515:GPS
439:or
424:On
342:sin
330:tan
286:tan
274:sin
222:bed
204:or
192:Dip
93:dip
72:or
60:In
1596::
878:.
839:.
817:.
807:44
805:.
786:.
782:.
763:.
759:.
737:.
707:^
664:^
623:.
599:^
589:.
573:^
559:.
536:^
499:.
475:A
212:.
166:.
142:,
138:,
134:,
130:,
123:.
64:,
53:,
914:e
907:t
900:v
886:.
825:.
821::
813::
790:.
788:4
658:.
593:.
351:)
327:(
318:=
295:)
271:(
262:=
34:.
20:)
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