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To get right to it:Segmentation vs the “inversion”

Geodetic slip rates and block modelsFault zones to link small faults and assign rates

modern

1500 A.D.

1500 B.C.

3000 B.C.

YoungSection

Old Section

BSSA: Biasi, 2002; Fumal, 2002; Scharer, 2007

MiddleSection

12 meters44 clastic layers15 earthquakes

4 meters44 clastic layers14 earthquakes

Composite Stratigraphic Column

Dated Interpolated

Calendar Year (A.D.)

Cum

ulati

ve T

hick

ness

(cm

)Cu

mul

ative

Fre

quen

cy

Sedimentation EventReturn Interval

Clastic Accumulation Rate(cm/yr)

37 yr

0.6 cm/yr

Young Section

Earthquakes

2 cm/yr

12 yr236 yr

0.4 cm/yr

Variation around avg thickness (25 cm) - Modeled Dates

-40

-20

0

20

40

60

80

100

500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000

Calendar Year

Clas

tic (c

m)

clastic

WW Young - Clastic Sedimentation Rates

0

200

400

600

800

1000

1200

500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000

C14 dated

interp

eqs

Age of debris flow layer is age of underlying peat.

avg avg

Age Range # eqs # DF layers

DF thickness DF RI

634 890 5 13 43 20

890 1191 2 6 15 50

1191 1338 1 1 65 147 W6

1338 1857 5 21 16 25

Starting w/ W13

Pallett Creek

With a sedimentation rate of ~1 m/100 yrs, and individual clastic units representing on average 5-10 years, we can distinguish events that are likely separated by decades.

Here are two earthquakes separated by just 20-30 cms, and thus likely 20-30 years (as the C-14 shows).

• Interseismic deformation due to plate convergence

Updip Deformation Sources

Trench Central OR Coast