revised: 05-Feb-2015

NMBGMR Draft Geologic Data Model - v. 1.0.4
SYMBOLOGY: Linear Features - Faults

In the interests of standardization and interoperability, we are migrating our geologic maps into the USGS NCGMP09 data model. However, our well data model is still actively being used. Documentation for the NMBGMR geology data model is being provided for users with legacy data in this model. We also hope that it will provoke discussion in the ongoing effort to improve NCGMP09 and other models.

This document indicates how faults portrayed on a geologic map should be coded in the data model. See the NMBGMR Symbol set (3.7 Mb PDF) for details on how our standard symbology is constructed. Node order for faults should be set such that the right side of the fault is down for every fault type.

Fault (line decoration)

(point data combined with basic line styles, and Fault_line)

Description Symbol Relevant Feature Classes Attributes set Comment
Fault-unspecified fault Fault_line, Fault_point Fault_line
 LineClass="fault"
FaultType="unknown"
Confidence="certain"
Exposure="exposed"
Feature_point:
FeatrClass="key locality" 		triangle indicates superior exposure (point data)
Fault-unknown dip fault Fault_line, Fault_point Fault_line:
 LineClass="fault"
FaultType="unknown"
Confidence="certain"
Exposure="concealed"
Fault_Symbol:
SymbolClass="D"
SymbolClass="U" 		"U" and "D" are hand placed points from
Fault-oblique-slip fault Fault_line, Fault_point

Fault_line:
LineClass="fault"
FaultType="oblique-slip"
Confidence="[variable]"
Exposure="[variable]"
Slipsense="oblique"
SubSlipSns="dextral"
Fault_point:
MappedFeat="TRUE"
LineClass="fault"
FaultType="normal"
SlipSense="dip-slip"
SubSlipSns="dextral"
Inclination="inclined"
DipDir=[355]
Dip=[60]
FltLnType="slickenline"
Trend=[010]
Plunge=[50]
Fault_Symbol:
SymbolClass="bar-ball"
SymbolClass="text"
SymbolType="history"
SymbolText="N,d"
RotaAngle=[variable]
Feature_point:
FeatrClass="key locality"

Decoration (bar+ball, dip, slickenlines, etc) are all point data that lie on the fault line. Data regarding fault type might either be duplicated for the line and the point data, or may be different for faults with different slip histories along strike.
Fault-reverse fault Fault_line, Fault_point

Fault_line:
LineClass="fault"
FaultType="reverse"
Confidence="[variable]"
Exposure="[variable]"
Slipsense="dip-slip"
Fault_Symbol:
SymbolClass="reverse teeth"
RotaAngle=[variable]

Teeth may be either placed by hand as points in Fault_Symbol or may be generated for a given line segment from the line attributes (line node order may need to be reversed to get the symbols on the correct side, but 'FltDipDir' in Fault_line can record the dip direction).
Fault-thrust fault Fault_line, Fault_point Fault_line:
LineClass="fault"
FaultType="dip-slip"
Confidence="[variable]"
Exposure="[variable]"
Slipsense="thust"
Fault_Symbol:
SymbolClass="thrust teeth"
RotaAngle=[variable]		 Teeth may be either placed by hand as points in Fault_Symbol or may be generated for a given line segment from the line attributes (line node order may need to be reversed to get the symbols on the correct side, but 'FltDipDir' in Fault_line can record the dip direction).
Fault-detachment fault Fault_line, Fault_point Fault_line:
LineClass="fault"
FaultType="dip-slip"
Confidence="[variable]"
Exposure="[variable]"
Slipsense="low-angle normal"
Fault_Symbol:
SymbolClass="detach teeth"
RotaAngle=[variable]		 Teeth may be either placed by hand as points in Fault_Symbol or may be generated for a given line segment from the line attributes (line node order may need to be reversed to get the symbols on the correct side, but 'FltDipDir' in Fault_line can record the dip direction).
Fault-strike-slip fault Fault_line, Fault_point

Fault_line:
LineClass="fault"
FaultType="strike-slip"
Confidence="[variable]"
Exposure="exposed"
Slipsense="sinestral"
Fault_Symbol:
SymbolClass="sinistral" RotaAngle=[variable]

 Strike-slip arrows are point data (one point for each arrow).
Fault-strike-slip concealed fault Fault_line, Fault_point

Fault_line:
LineClass="fault"
FaultType="strike-slip"
Confidence="[variable]"
Exposure="concealed"
Slipsense="sinestral"
Fault_Symbol:
SymbolClass="sinistral" RotaAngle=[variable]

 Strike-slip arrows are point data (one point for each arrow).
Fault-complex history fault Fault_line, Fault_point

Fault_line:
LineClass="fault"
FaultType="oblique-slip"
Confidence="[variable]"
Exposure="obscured"
Slipsense="dip-slip"
SubSlipSns="strike-slip"
Ancestry="[e.g.] Laramide sinestral strike slip"
Fault_Symbol:
SymbolClass="bar-ball"
SymbolClass="sinistral" RotaAngle=[variable]

  
Fault-scarp fault Fault_line

Fault_line:
LineClass="fault scarp"
FaultType="dip-slip"
Slipsense="Right-side down"
Confidence="[variable]"
Exposure="obscured"

 Teeth should be generated from the line attributes (line node order may need to be reversed to get the symbols on the correct side, but 'SlipSense' in Fault_line can record the down side of the scarp if FltDipDir is unknown).
Breccia-zone breccia

Geo_poly

Feature_point

Geo_poly:
GeoID=[variable-hostrock]
Modified="breccia" Feature_point:
FeatureClass="breccia-symbol"

 If breccia occupies a mappable area, record in Geo_poly, if breccia is isolated or along a fault, record as point data in Feature_point.
Ductile shear-zone fault Fault_line

Fault_line:
LineClass="shear zone "
FaultType="[variable]"
Confidence="[variable]"
Exposure="[variable]"
Slipsense="[variable]"