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Unformatted text preview: E age on West Tahoe Fault, 4.1-4.5 ka; Incline
Village Fault, 0.6 ka; Stateline/North Tahoe
Size of MRE rupture: West Tahoe Fault, ~3.7-4.1
m; Incline Village, ~3-3.5 m; Stateline/North
Total extension across basin is ~0.5 mm/yr.
sedimentation rate extrapolation suggest ~60
ka age of slide, maybe younger.
~2000-3000 year potential recurrence interval
for tsunami-generating M7 earthquake.
West Tahoe Fault: ~55 km length has a potential
of a M7.3 rupture. Figure 19. Comparison of the West Tahoe fault and the GF; both faults exhibit similar range front morphology, strike, and length.
Together, these faults appear to be accommodating most of the extension (2–3 mm=yr) occurring within the northern Walker Lane at
the latitude of Lake Tahoe. second method, the offset fan surface offshore Sugar Pine
Point (Figs. 16 and 18) is presumed to be inactive since
the Tioga glacial retreat (Dingler, 2007). The 10.5 m offset
(Fig. 18) since 13 k.y. B.P. also produces a maximum vertical
slip rate of ∼0:8 mm=yr. Overall, these data give rise to a
vertical displacement rate between 0.4 and 0:8 mm=yr since
the end of Tioga glaciation, which is slightly higher than
the 0:5 mm=yr minimum slip-rate estimate (over the last
∼20 ka) reported by Kent et al. (2005). An extension rate
can be estimated from vertical slip rate assuming simple fault
geometry. For a 60° dipping normal fault, the vertical deformation rate is transformed into an extension rate between 0.3
and 0:5 mm=yr. The slip rate along the WTDPF may be
higher than estimated because the MRE occurred at 4.1–
4.5 k.y. B.P. and, presumably, additional strain has accumulated during the quiescent interval. With a slip rate between
0.4 and 0:8 mm=yr, it is possible that ∼3 m of elastic strain has accumulated across the WTDPF. Coseismic slip of 3 m
on the WTDPF could generate an M ≥ 7 event. The GF
(Fig. 19) has a vertical deformation rate of 2–3 mm=yr over
the last 2 k.y. (Ramelli et al., 1999), which can be converted
to a 1:2–1:7 mm=yr extension rate (also assuming 60° dip).
The combined extension rates of the GF and the WTDPF are
consistent with the 2–3 mm=yr GPS derived extension rates
across the Sierra Nevada frontal fault zone (Hammond and
Thatcher, 2004, 2007).
Earthquake triggering associated with normal fault
earthquakes and resulting static stress changes have been
used to explain normal fault event sequences (Nostro et al.,
1997); therefore, it is important to compare paleoearthquake
records between neighboring faults. Events on the IVF and
GF at ∼500 yr B.P. (Ramelli et al., 1999; Dingler, 2007) suggest a possible relationship in the rupture timing, but the age
uncertainty is large and coincident timing could also be re- Persistent Drought—60% of “normal”, Medieval Period
Rooted Trees 110’
Cedar Grove Cry...
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