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CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to Korean Patent Application No. 10-2012-0027711 filed on Mar. 19, 2012 and all the benefits accruing therefrom under 35 U.S.C. §119, the contents of which are incorporated by reference in their entirety. 
     BACKGROUND 
     The present disclosure relates to an apparatus for measuring geologic strike and dip. More particularly, the disclosure relates to an apparatus for facilely measuring strike and dip of a bedding plane and an auxiliary apparatus for measuring strike and dip. 
     Strike and dip refer to the attitude of a geologic formation. Structural geology uses measurements of present day rock geometries to determine the history of deformation in various geologic strata. In general, a direction of an intersection defined by a bedding plane and a horizontal plane is referred to as strike, and an angle between the bedding plane and the horizontal plane is referred to as dip. In field work, strike is typically measured by supporting a side surface of a compass on the bedding plane and leveling the compass to read a North direction of the compass. Also dip is measured by locating an inclinometer in a direction perpendicular to the horizontal plane to read an angle of the inclinometer. 
     One popular device for field mapping geological formation strata is known as a Brunton compass. When strike is measured, however, it is difficult to support only the side surface of the compass to maintain a horizontal posture of the compass. Also, when dip is measured, it is difficult to maintain the state in which an inclinometer is vertically disposed with respect to the horizontal plane. Thus, it is often difficult to reproducibly and conveniently measure strike and dip using merely a compass and inclinometer. In addition it is inconvenient to separately and respectively measure strike and dip. 
     SUMMARY 
     The present disclosure provides an apparatus for measuring geologic strike and dip which can reproducibly and conveniently measure strike and dip at the same time. 
     The present disclosure also provides an auxiliary apparatus for measuring strike and dip which can reproducibly and conveniently measure strike and dip at the same time. 
     In accordance with an exemplary embodiment, an apparatus for measuring strike and dip includes: a support plate; a first rotation plate disposed on the support plate and parallel to the support plate, the first rotation plate being rotatable parallel to the support plate. A second rotation and pivot plate is hinge-coupled to the first rotation plate and the second rotation and pivot plate is rotatable about a hinge shaft. A protractor is configured to read an angle between the first rotation plate and the second rotation plate and a measuring unit including a compass disposed on the second rotation plate. 
     The measuring unit further includes an X-Y plane level gauge configured to confirm horizontal posture of the second rotation and pivot plate and a parallel posture of a strike line with a horizontal geologic plane. A protractor may be disposed on a side surface of the hinge shaft. A support plate has graduations along a circumference of the first rotation plate to confirm a rotation angle of the first rotation plate with respect to the support plate. 
     The apparatus may further include one or more auxiliary plates disposed parallel and rotatably connected to the support plate. The auxiliary plate is configured to assist the support plate so that the support plate is disposed parallel to a bedding plane. 
     In accordance with another exemplary embodiment, an auxiliary apparatus for measuring geologic strike and dip includes: a support plate; a first rotation plate disposed on the support plate and parallel to the support plate, the first rotation plate is rotatable parallel to the support plate about an axis normal to the first rotation plate and the support plate. A second rotation and pivot plate is hinge-coupled to the first rotation plate and rotated about a hinge shaft. The hinge shaft extends through and perpendicular to a central rotation axis projecting normal to the first rotation plate. The second rotation plate is configured to support a measuring unit and a protractor is vertically disposed with respect to the first rotation plate. The protractor is configured to confirm an angle between the first rotation plate and the second rotation plate and is mounted on a side surface of the hinge shaft. 
     A support plate may have graduations along a circumference of the first rotation plate to confirm a rotation angle of the first rotation plate with respect to the support plate when the hinge axis is parallel to a geologic horizontal plane. 
     The auxiliary apparatus may further include an auxiliary plate disposed parallel and rotatably connected to the support plate, the auxiliary plate is configured to assist the support plate so that the support plate is disposed parallel to a bedding plane. The second rotation plate may further include an attachment member configured to releasably connect the measuring unit to the support plate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments will be understood in more detail from the following description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a pictorial illustration of a geological outcropping where it is desirable to measure strike and dip values for the formation; 
         FIG. 2  is a graphic representation of a geologic plane similar to a rock formation plane depicted in  FIG. 1  with an addition of imaginary horizontal and vertical planes with lines depicting strike and dip for the exposed formation; 
         FIG. 3  is a plan view of an apparatus for measuring strike and dip in accordance with an exemplary embodiment; 
         FIG. 4  is a side view of the apparatus for measuring strike and dip shown in  FIG. 3 ; 
         FIGS. 5 and 6  are views of a state in which the apparatus for measuring strike and dip of  FIG. 3  is placed on a bedding plane where  FIG. 5  is positioned on a bed in a mirror image posture of the apparatus shown in  FIG. 4 ; 
         FIG. 7  is a plan view of an auxiliary apparatus for measuring strike and dip in accordance with an exemplary embodiment; and 
         FIG. 8  is a side view of the auxiliary apparatus for measuring strike and dip shown in  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Context of the Invention 
     Geological features of bed planes, fold axes, faults and other geologic structures can be described using measurements of strike and dip. 
     In  FIG. 1  a generally horizontal ground earth surface  10  has an outcropping of rock strada or beds  20  and  30 . Strike is a measure of an angle created between a strike line  40  on the rock strada  20  drawn parallel to a horizontal ground surface and magnetic North as determined by a compass. 
     As shown in  FIG. 2  dip is an angle within a plane  50  that is vertical to a horizontal plane  60  extending through the strike line  40 . The dip angle is an angle in the vertical plane  50  from the horizontal plane  60  extended down to the line of intersection of the vertical plane  50  with the geologic strata bedding  20 . Dip is perpendicular to strike and has both a compass direction and an angle. Structural geologists designate strike 15 degrees East of North and having a dip 20 degrees Southeast as N15E, 20SE. 
     Strike and Dip Measurement Apparatus 
     An apparatus for measuring strike and dip and an auxiliary apparatus for measuring strike and dip in accordance with an exemplary embodiment will be described in detail with reference to the accompanying drawings. Since the present disclosure may have diverse modified embodiments, preferred embodiments are illustrated in the drawings and are described in the detailed description of the invention. However, this does not limit the present disclosure to these specific embodiments and it should be understood that the present disclosure covers all the modifications, equivalents, and replacements within the idea and technical scope of the present disclosure. In a description of the drawings, like reference numerals in the drawings denote like elements. In the drawings, dimensions of structures may be enlarged or exaggerated for clarity. 
     It will be understood that although the terms of first and second are used herein to describe various elements, these elements should not be limited by those terms. Terms are only used to distinguish one component from other components. Therefore, a component referred to as a first component in one embodiment can be referred to as a second component in another embodiment. 
     In the following description, the technical terms are used only for explaining a specific exemplary embodiment while not limiting the present disclosure. The terms of a singular form may include plural forms unless as statement is made to the contrary. The meaning of ‘include’ or ‘comprise’ specifies a property, a numeral, a step, an operation, an element or a combination thereof, but does not exclude other properties, numerals, steps, operations, elements or combinations thereof. 
     Unless terms used in the present invention are defined differently, the terms should be construed with a meaning known to those skilled in the art. Terms such as, for example strike and dip should be construed as having meanings matched with contextual meanings in the art. 
       FIG. 3  is a plan view of an apparatus for measuring geological strike and dip in accordance with an exemplary embodiment.  FIG. 4  is a side view of the apparatus for measuring strike and dip disclosed in  FIG. 3 .  FIGS. 5 and 6  are views of a state in which the apparatus for measuring strike and dip of  FIG. 3  is placed on a bedding plane. 
     Referring now specifically to  FIGS. 3 to 6 , an apparatus  100  for measuring geological strike and dip includes a support plate  110 , a first rotation plate  120 , a second rotation and pivot plate  130 , a protractor  140 , a measuring unit  150 , and auxiliary plates  160 . 
     The support plate  110  may have various geometric plate shapes. For example, the support plate  110  may have a square plate shape. Thus, the support plate  110  may contact a bedding plane  20  and be disposed parallel to the bedding plane  20 . 
     The first rotation plate  120  is disposed parallel to the support plate  110  and is mounted on the support plate  110 . The first rotation plate  120  is circular and rotatably connected to the support plate  110 . The first rotation plate  120  and the support plate  110  are connected to each other by a central rotation shaft  112  mounted on the support plate  110  and extends perpendicular to the support plate  110  and the first rotation plate  120 . Thus, the first rotation plate  120  may be rotated parallel to the support plate  110 . 
     The first rotation plate  120  may have a circular plate shape and thus be easily fixed. Here, a perpendicular rotation shaft  112  is connected to a center location of the first rotation plate  120 . Alternatively, the first rotation plate  120  may have various plate shapes such as a semicircular or polygonal plate shape. 
     The support plate  110  has graduations  114  marked along a circumference of the first rotation plate  120 . Thus, a rotation angle of the first rotation plate  120  with respect to the support plate  110  may be easily determined using the graduations  114 . A base line marker graduation combination  116  may be displayed on each of the first rotation plate  120  and the support plate  110  to confirm an angle between the base lines, thereby more easily confirming the rotation angle of the first rotation plate  120 . 
     The second rotation and pivot plate  130  is disposed on the first rotation plate  120  and is hinge-coupled to pivot with respect to the first rotation plate  120 . The second rotation plate  130  may have a rectangular plate shape. Also, the second rotation plate  130  has a side surface hinge-coupled to the first rotation plate  120 . The second rotation plate  130  is mounted to pivot around a hinge shaft  122 . When the first rotation plate  120  has a circular plate shape, the hinge shaft  122  may be disposed crossing a diameter of the first rotation plate  120  and an imaginary central longitudinal axis of the hinge shaft  122  intersects at a right angle an imaginary central longitudinal axis of the rotation shaft  112 . 
     Each of the first and second rotation plates  120  and  130  may be adjusted in rotation in a state where the support plate  110  is placed on the bedding plane  20  to dispose the second rotation plate  130  parallel to a horizontal plane. The horizontal plane may be a virtual sea level, i.e., a virtual plane perpendicular to the direction of gravity. Since the support plate  110  is disposed on the bedding plane  20  and parallel to the first rotation plate  120 , the bedding plane  20  is parallel to the first rotation plate  120 . When the second rotation plate  130  is disposed parallel to the horizontal plane, an angle between the first rotation plate  120  and the second rotation plate  130  is equal to that between the bedding plane  20  and the horizontal plane. That is, an angle between the first rotation plate  120  and the second rotation plate  130  is the dip measurement of the bedding plane  20 . 
     When the second rotation plate  130  is disposed parallel to the horizontal plane, the protractor  140  affixed to the hinge shaft  122  reads an angle between the first rotation plate  120  and the second rotation plate  130 . Since the angle between the first rotation plate  120  and the second rotation and pivot plate  130  is equal to the dip of the bedding plane  20 . The dip of the bedding plane  20  may be determined by reading the angle between the first rotation plate  120  and the second rotation plate  130 . 
     The protractor  140  may be vertically disposed with respect to the first rotation plate  120 . For example, the protractor  140  may be disposed on a side surface of the hinge shaft  122 . The protractor  140  is attached to a side surface of the hinge shaft  122 , with graduations for measuring an angle directly displayed on the side surface of the hinge shaft  122 . Here, a center of the protractor  140  is coaxially disposed with respect to an imaginary central longitudinal axis of the hinge shaft  122 . 
     To easily measure the angle between the first rotation plate  120  and the second rotation plate  130 , a base line  124  may be displayed on a side surface of the second rotation plate  130 . 
     The measuring unit  150  includes a compass  152 . The compass is disposed on the second rotation and pivot plate  130 . When the second rotation and pivot plate  130  is disposed parallel to the horizontal plane, the compass  152  functions to measure a direction of an intersection between the first rotation plate  120  and the second rotation plate  130  with respect to North. As indicated above, since the bedding plane  20  and the first rotation plate  120  are parallel to each other, and a geological horizontal plane and the second rotation plate  130  are parallel to each other, the intersection between the first rotation plate  120  and the second rotation plate  130  is equal to the strike line of the bedding plane  20 . The strike angle can be determined from the intersection between the first rotation plate  120  and the second rotation plate  130  as measured using the compass  152  on the basis of a magnetic North to measure the strike angle of the bedding plane  20 . 
     The measuring unit  150  further includes an X-Y axis level gauge  154 . The level gauge  154  is disposed on the second rotation and pivot plate  130 . Thus, a horizontal posture of the second rotation plate  130  in an orientation where the hinge imaginary central longitudinal axis is perpendicular to the direction of gravity is precisely confirmed using the level gauge  154 . The compass  152  and the level gauge  154  may be integrated with each other. Alternatively, the compass  152  and the level gauge  154  may be separately provided on the second rotation and pivot plate  130 . 
     The measuring unit  150  may be fixed on the second rotation plate  130 . Alternatively, the measuring unit  150  may be detachably disposed on the second rotation plate  130 . 
     When the second rotation plate  130  is horizontally disposed as shown in  FIG. 5 , the first and second rotation plates  120  and  130  may be maintained in a rotated state so as to easily measure the rotation angle of the first rotation plate  120  with respect to the support plate  110  and the pivot angle between the first rotation plate  120  and the second rotation plate  130 . The support plate  110  and the first rotation plate  120  are relatively firmly coupled to each other, and the first rotation plate  120  and the second rotation plate  130  are relatively firmly hinge-coupled to each other to maintain the rotated state of the first rotation plate  120  and the second rotation plate  130 . Alternatively, each of the first and second rotation plates  120  and  130  may be releasably fixed using a separate angle securing member. 
     The support plate  110  is disposed parallel to a lineation having line shapes arranged on the bedding plane  20  and parallel to the bedding plane  20 , and the second rotation plate  130  is horizontally disposed, the rotation angle of the first rotation plate  120  with respect to the support plate  110  may be determined to measure a rake angle that is an angle between the strike of the bedding plane  20  and the line structure. 
     Also, when the support plate  110  is disposed parallel to the lineation and perpendicular to the bedding plane  20  on the bedding plane  110 , and the second rotation plate  130  is horizontally disposed, the rotation angle of the first rotation plate  120  with respect to the support plate  110  may be measured to measure plunge that is an angle between the horizontal plane and the line structure. 
     Auxiliary plates  160  are mounted in a posture parallel and pivotally connected to the support plate  110 . The auxiliary plates  160  may be disposed on each of two edges of the support plate  110 . The auxiliary plates  160  may assist the support plate  110  so that the support plate  110  is disposed parallel to the bedding plane  20 . For example, as shown in  FIG. 4 , when only a portion of the bedding plane  20  is exposed so that the support plate  110  does not stably contact the bedding plane  20 , the auxiliary plates  160  may be unfolded so that the support plate  110  and an auxiliary plate  160  contacts the bedding plane  20  at the same time. Thus, even though only a portion of the bedding plane  20  is exposed, the support plate  110  may be disposed parallel to the bedding plane  20 . 
     The apparatus  100  for measuring strike and dip is operable to measure the strike and dip of the bedding plane  20  at the same time. Also, in the apparatus  100  for measuring strike and dip, since the support plate  110  may be disposed parallel to the bedding plane  20 , strike and dip of the bedding plane  20  may be precisely and reproducibly measured. Also, in the apparatus  100  for measuring the strike and dip, even though only a portion of the bedding plane  20  is exposed, the support plate  110  may be disposed parallel to the bedding plane  20  using the auxiliary plates  160  as shown in  FIG. 6 . 
     The apparatus  100  for measuring strike and dip may also be used for measuring rake angle and plunge of lineation. 
     Method for Measuring Strike and Dip 
     In operation the apparatus  100  for measuring strike and dip is seated on the bedding plane  20  so that the bedding plane  20  and the support plate  110  are parallel to each other. When only a portion of the bedding plane  20  is exposed, the support plate  110  is disposed parallel to the bedding plane  20  using an auxiliary plate  160 . 
     Thereafter, the first and second rotation plates  120  and  130  are rotated and pivoted to dispose the second rotation plate  130  in a horizontal state with the imaginary central longitudinal axis of the hinge  122  perpendicular to the direction of gravity as shown in  FIG. 5 . The second rotation plate  130  angles are as confirmed using the X-Y level gauge  154 . 
     A direction of an intersection between the first and second rotation plates  120  and  130  may be measured using the compass  152  on the basis of a magnetic North to measure the strike of the bedding plane  20 . Also, an angle between the first and second rotation plates  120  and  130  may be measured using the protractor  140  to measure the dip of the bedding plane  20 . 
     Auxiliary Apparatus 
       FIG. 7  is a plan view of an auxiliary apparatus for measuring strike and dip in accordance with an exemplary embodiment.  FIG. 8  is a side view of an auxiliary apparatus for measuring strike and dip shown in  FIG. 7 . 
     Referring to  FIGS. 7 and 8 , an apparatus  200  for measuring strike and dip includes a support plate  210 , a first rotation plate  220 , a second rotation plate  230 , a protractor  240 , and an auxiliary plate  260 . 
     Since the first rotation plate  220 , the second rotation and pivot plate  230 , the protractor  240 , and the auxiliary plate  260  have substantially the same structure as those of the first rotation plate  120 , the second rotation plate  130 , the protractor  140 , and the auxiliary plate  160  described with reference to  FIGS. 3 to 6 , their detailed description will not be repeated. 
     Additionally, the second rotation plate  230  supports a measuring unit  250  for measuring strike of a bedding plane and a horizontal posture of the second rotation plate  230 . 
     The measuring unit  250  may include a compass for measuring strike angle of the bedding plane  20  and an X-Y level gauge  254  for measuring the horizontal posture of the second rotation plate  230  in a posture with the axis of the hinge between the first and second plates perpendicular to a line of gravity. The compass and the level gauge may be integrated or separated from each other. 
     Alternatively, the measuring unit  250  may include a compass application for measuring the strike of the bedding plane and a mobile phone in which a level gauge application for measuring the horizontal posture of the second rotation plate  230  is installed. 
     When the second rotation plate  230  is horizontally disposed, the measuring unit  250  is operable to measure a direction of an intersection between the first rotation plate  220  and the second rotation and pivot plate  230 . Since the bedding plane  20  and the first rotation plate  220  are parallel to each other, and a horizontal plane and the second rotation plate  230  are parallel to each other, the direction of the intersection between the first and second rotation plates  220  and  230  is equal to the strike line of the bedding plane  20 . Thus, the direction of the intersection between the first rotation plate  220  and the second rotation plate  230  may be measured using the measuring unit  250  on the basis of a magnetic North to measure the strike of the bedding plane  20 . 
     Also, the measuring unit  250  may be disposed on the second rotation plate  230  to precisely confirm the horizontal and rotation orientation of the second rotation and pivot plate  230 . 
     The second rotation plate  230  may further include an attachment member  232  for securing the measuring unit  250 . The attachment member  232  operably secures the measuring unit  250  to prevent the measuring unit  250  placed on the second rotation plate  230  from be separated from the second rotation plate  230 . The attachment member  232  may have various mechanical forms such as, for example, a clamp and a clip. 
     Also, the second rotation plate  230  may further include a groove (not shown) for receiving and securing the measuring unit  250 . Since the measuring unit  250  is received in the groove, the measuring unit  250  may be precisely seated on the second rotation plate  230  to more firmly fix the measuring unit  250  with respect to the second rotation plate  230 . 
     The apparatus  200  for measuring the strike and dip may include the measuring unit  250  for measuring the strike of the bedding plane and the horizontal posture of the second rotation plate  230  to measure strike and dip of the bedding plane  20  at the same time. Also, in the apparatus  200  for measuring strike and dip, since the support plate  210  may be disposed parallel to the bedding plane, the strike and dip of the bedding plane may be precisely and reproducibly measured. In the apparatus  200  for measuring strike and dip, even though only a portion of the bedding plane  20  is exposed, the support plate  210  may be disposed parallel to the bedding plane  20  using the auxiliary plate  260 . 
     The apparatus  200  for measuring the strike and dip may also be used for measuring rake angle and plunge of the lineation. 
     The process for measuring strike and dip of the bedding plane  20  using the apparatus  200  for measuring strike and dip may be performed with the same process as the apparatus  100  for measuring strike and dip, after the measuring unit  250  is mounted on the second rotation and pivot plate  230 . 
     As described above, an apparatus  100  for measuring strike and dip and an auxiliary apparatus  200  may measure strike and dip of the bedding plane  20  at the same time using an angle of a compass and an angle between the first and second rotation plates when the second rotation plate is horizontally disposed. Also, in the apparatus for measuring strike and dip and the auxiliary apparatus, since the support plate is stably disposed on the bedding plane, the strike and dip of the bedding plane may be reproducibly and conveniently measured. 
     Although the exemplary embodiments have been described with reference to the specific embodiments, they are not limited thereto. Therefore, it will be readily understood by those skilled in the art that various modifications and changes can be made thereto without departing from the spirit and scope of the present disclosure defined by the appended claims.

Summary:
An apparatus for measuring geologic strike and dip of a formation. The apparatus includes a support plate, a first rotation plate disposed on the support plate and parallel to the support plate, the first rotation plate being rotatable parallel to the support plate, a second rotation plate hinge-coupled to the first rotation plate, the second rotation plate being rotatable about a hinge shaft, a protractor configured to read an angle between the first rotation plate and the second rotation plate; and a measuring unit including a compass disposed on the second rotation plate.