Oriented Core Structural Calculator

True plane orientation from a single oriented-core measurement

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Step 1

Drillhole orientation

Azimuth is clockwise from true north. Enter the inclination magnitude, then select − Downhole or + Uphole.

Drillhole azimuth

Drillhole inclination magnitude

Step 2

Structure measurement

Alpha angle

Beta angle

Apparent Thickness / Downhole Intercept (m) — optional

Alpha angle

Measurement units

Enter diameterEnter circumference

Core size

Core diameter

Core circumference

Arc distance from reference line

Direction around core

Apparent Thickness / Downhole Intercept (m) — optional

Calculated Beta: —

Measurement Convention

Displayed convention: view the core looking downhole. Beta starts at the bottom-of-hole/reference line and increases clockwise. Alpha is the acute angle between the structure plane and the core axis: 0° is parallel to the axis; 90° is perpendicular.

Counterclockwise arc measurements are converted to the equivalent clockwise Beta. The Alpha/Beta rotation and geographic transformation follow the supplied Alpha-Beta Quick Office workbook, with negative field inclination converted to positive downhole plunge for the calculation.

True thickness assumptions

True thickness assumes approximately parallel planar boundaries and an intercept measured along the drillhole axis. Curved, folded, irregular, or nonparallel contacts produce only an approximation. For long intervals or curved holes, use the local drillhole orientation representative of the measured interval.

Calculated Structural Orientation

Right-Hand Rule

True Dip—

Dip Direction—

Strike—

Strike / Dip— / —

Enter a measurement and press Calculate.

Orientation Preview

Compass & plane

Structure strikeDip directionDrillhole direction

Interactive 3D Preview

Drillhole & structural plane

Calculate an orientation to build the 3D model.

Strike—

Dip—

Dip direction—

DrillholeStrikeDown-dip

The red collar is the orbit center. Drag to rotate; Shift-drag or right-drag to pan; scroll or pinch to zoom.

Display

Result precision

All calculations retain full floating-point precision. Rounding applies only to displayed angles; thickness remains at two decimal places.

Optional AnalysisApparent Dip & Drillhole Section ViewVertical section aligned with the drillhole azimuth

Apparent dip in section—

Acute structure trace ↔ drillhole—

Drillhole traceProjected structure traceApparent dip from horizontalTrace-to-drillhole angle

The apparent dip is the structure’s inclination in the vertical drillhole-azimuth section. The trace-to-drillhole value is a separate acute angle between the two projected lines.