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History of Investigation
Anderson (1951) classified faults into normal,
strike-slip and reverse faults (thrusts) depending
on which of the three principal stresses is the
vertical one.
IAU Descriptor Term
▶ Fossa
See Also
▶ Fracture
▶Graben
References
Anderson EM (1951) The dynamics of faulting and dyke
formation with applications to Britain, 2nd edn. Oliver
& Boyd, Edinburgh
Caine JS, Evans JP, Forster CB (1996) Fault zone archi-
tecture and permeability structure. Geology
24:1025–1028
Davis HD, Reynolds SJ (1996) Structural geology of rocks
and regions, 2nd edn. Printed in the United States,
Wiley & Sons, p 776
Ferrill DA, Morris AP (2003) Dilational normal faults.
J Struct Geol 25:183–196
Ferrill DA, Wyrick DY, Morris AP, Sims DW, Franklin
NM (2004) Dilational fault slip and pit chain formation
on Mars. GSA Today 14(10):9
Fossen H (2010) Structural geology. Cambridge Univer-
sity Press, Cambridge, p 463
Kattenhorn SA (2011) Terrestrial dilational faults: analogs
for normal faults on Mars and possibly icy moons.
Paper No. 284-12, GSA annual meeting in Minneapo-
lis, 9–12 Oct 2011
Kolyukhin D, Torabi A (2012) Statistical analysis of the
relationships between faults attributes. J Geophys Res
117:14. doi:10.1029/2011JB008880, B05406
Martel SJ, Tulasi I (2009) Formation of pit chains and pit
crater chains at Kilauea Volcano, Hawaii, American
Geophysical Union. Fall meeting 2009, abstract
#V23E-2159
Okubo CH, Schultz RA (2004) Mechanical stratigraphy in
the western equatorial region of Mars based on thrust
fault-related fold topography and implications for
near-surface volatile reservoirs. Geol Soc Am Bull
116:594–605
Rothery DA, Massironi M (2010) Beagle rupes – evidence
of a basal decollement of regional extent in Mercury’s
lithosphere. Icarus 209:256–261
Schultz RA, Hauber E, Kattenhorn SA, Okubo CH,
Watters TR (2010) Interpretation and analysis of plan-
etary structures. J Struct Geol 32:855–875
Sibson RH (1996) Structural permeability of fluid-driven
fault-fracture meshes. J Struct Geol 18(8):1031–1042
Torabi A, Berg SS (2011) Scaling of fault attributes:
a review. Mar Pet Geol 28:1444–1460
Watters, TR, Schultz, RA (eds) (2010) Planetary tectonics.
Cambridge University Press, Cambridge, UK, p 556
Fault Terminations
▶ Secondary Fault
Faulted Band (Europa)
Michelle Selvans
Center for Earth and Planetary Studies, National
Air and Space Museum, Smithsonian Institution,
Washington, DC, USA
Definition
Tectonically deformed dilational bands, showing
lineations caused by normal faults.
Category
A type of ▶ lineated band on Europa.
Synonyms
Ridged band (Stempel et al. 2005); not
recommended
Description
Linear to curvilinear features having grossly axi-
symmetric morphology, with a narrow, linear
Faulted Band (Europa) 761
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central trough flanked by a hummocky textured
zone, beyond which are subparallel ridges and
troughs; commonly showing a ridge at the sharp
boundary with the surrounding terrain (Prockter
et al. 2002).
Interpretation
They appear to be faulted smooth bands (Prockter
and Patterson 2009). Subparallel ridges and
troughs are similar in their characteristics to
imbricate fault blocks. They have distinct troughs
along their axis, inferred to be the spreading axis.
Older faults translate further away from the
actively spreading central axis over time. Tilted
fault blocks in those bands with low spreading
rate may create repeating valleys and ramparts
(Kattenhorn and Hurford 2009).
Formation
They are thought to be formed by extensional
stresses (e.g., Figuerdo and Greeley 2004;
Nimmo 2004), through exploitation of
a preexisting double ridge, with the ridges mov-
ing apart and filling in with buoyant ductile mate-
rial from below that cooled and faulted as it
moved away from the central trough.
Degradation
▶Lineated band
Studied Locations
For example, Yelland and Ino Lineae, in
Argadnel Region (the “wedges region”), which
intersect near 16S, 196W (Fig. 1).
Astrobiological Significance
These features likely formed while warm, ductile
ice (which could have been coupled to the under-
lying, global ocean) was exposed at the surface.
Terrestrial Analog
The central trough, hummocky zone, and series
of troughs and ridges have been modeled using
the analog of a mid-ocean ridge (Stempel
et al. 2005).
See Also
▶Band (Europa)
▶Normal Fault
Faulted Band (Europa), Fig. 1 Anatomy of a faulted
band. A central trough runs along the central axis, inferred
to be a spreading axis. A hummocky zone is found along
both sides of the central trough; outside of this are wide
lineated zones running subparallel to the margins
(Prockter and Patterson 2009, Fig. 11) (1) ridged plains,
(2) lineated zone, (3) hummocky zone, (4) central trough.
Galileo 12ESWEDGE_02 mosaic (NASA/JPL/ASU)
762 Faulted Band (Europa)
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References
Figuerdo PH, Greeley R (2004) Resurfacing history of
Europa from pole-to-pole geological mapping. Icarus
167:287–312
Kattenhorn SA, Hurford TA (2009) Tectonics of Europa.
In: Pappalardo RT, McKinnon WB, Khurana K (eds)
Europa. University of Arizona Press, Tucson,
pp 199–236
Nimmo F (2004) Dynamics of rifting and modes of exten-
sion on icy satellites. J Geophys Res 109:E01003.
doi:10.1029/2003JE002168
Prockter LM, Patterson GW (2009) Morphology and evo-
lution of Europa’s ridges and bands. In: Pappalardo
RT, McKinnon WB, Khurana K (eds) Europa. Univer-
sity of Arizona Press, Tucson, pp 237–259
Prockter LM, Head JW, Pappalardo RT, Sullivan R,
Clifton AE, Giese B, Wagner R, Neukum G (2002)
Morphology of europan bands at high resolution:
a mid-ocean ridge type rift mechanism. J Geophys
Res 107. doi:10.1029/2000JE001458
Stempel MM, Barr AC, Pappalardo RT (2005) Model
constraints on the opening rates of bands on Europa.
Icarus 177:297–304
Feather Fracture
▶ Secondary Fault
Felsenmeer
▶Blockfield (Periglacial)
Festoon (Lava)
Scott S. Hughes1 and Stephanie C. Werner2
1Department of Geosciences, Idaho State
University, Pocatello, ID, USA
2Comparative Planetology, Centre for Earth
Evolution and Dynamics, University of Oslo,
Oslo, Norway
Definition
Pattern of arcuate, bent, or looped ridges exposed
on the surface of a lava flow or on an outcrop of
cross-bedded sediment.
Synonyms
Corda; Festoon deposit; Festoon ridge
Description
Pahoehoe festoon or festoon ridge (corda) is
a subtype of ▶ pressure ridge. Ridges on
pahoehoe lava flows are regularly spaced

5–50 cm apart, where the ropy surface is
dragged by the underlying molten lava into fes-
toon patterns. The morphology of festoon-like
ridges and flow bands is often characterized
using fractal geometry of lava flow surfaces;
sizes of festoon ridges range from small-scale
2–20 cm pahoehoe ropes to meso- and large-
scale features 1–100 m high with spacings rang-
ing from 10 m to several hundred meters apart
(on rhyolite flows) (Theilig and Greeley 1986,
1987).
Interpretation
The lava’s surface crust is folded when in
a semisolid state during the final still-mobile
stages of emplacement as viscosity increases
due to cooling.
Formation
Emplaced as sheet flows from basaltic flood lava
eruptions (Theilig and Greeley 1987). The for-
mation and growth of arcuate ridges oriented
perpendicular to lava flow direction depend on
the physical properties of the flow, specifically
the viscosity. The ridges could result from com-
pression of the fluid in which the viscosity
decreases with depth and form in the cooling
upper layer of the flow. The ridge size and spac-
ing depends on flow rheology, thermal boundary
layer thickness, and applied stress (Theilig and
Greeley 1986).
Festoon (Lava) 763
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