Tectonics
Supporting Information for
Neotectonic characteristics along the eastern flank of the Central Range in the
active Taiwan orogen inferred from fluvial channel morphology
Yi-Wei Chen1, J. Bruce H. Shyu1, Chung-Pai Chang2
1: Department of Geosciences, National Taiwan University, Taipei, Taiwan.
2: Center for Space and Remote Sensing Research, National Central University, Chungli, Taiwan.
Additional Supporting Information (Files uploaded separately)
Captions for Tables S1 to S2 and Figures S1 to S3
Introduction
The Supporting Information includes two data set tables and three supplementary
figures. The first table is the knick point data of the main trunks of all 20 rivers analyzed
in this study. The second table provides information of the concavity values (θ) and river
steepness index (ksn) of all main trunk segments of the 20 rivers analyzed in this study.
The first figure shows the χ plot and the SA plot of all other rivers than those already
shown in Figure 3. The second figure shows average ksn values of all river groups
identified in this study. The third figure shows the relationship between mean elevations
and the ksn values of the most downstream segments of the analyzed rivers.
In Table S1, the first column is the number of the knick points. The numbering system
correspond with the number of river basins shown in Figure 2. If there are more than
one knick points along a river, the knick points are numbered from downstream to
upstream. The second and third columns corresponds to the longitude (E) and latitude
(N) of the knick points, in degrees. The fourth column is the distance of the knick points
from the drainage divide, in meters. The fifth column is the elevation of the knick points,
also in meters. The sixth column is the upstream drainage area of the knick points, in
square meters. The last column is the type of the knick points, following the description
of Kirby and Whipple [2012].
In Table S2, the first column is the number of the river segments. The first number
correspond with the number of river basins shown in Figure 2. If there are more than
one segments along a river, the second number is the number of segments, which are
numbered from downstream to upstream. The second column is the river steepness
index (ksn) of the river segment, with the third column indicates the standard deviation in
2σ. The fourth column indicates the reference concavity value when calculating the ksn.
The fifth column is the concavity value (θ) of the river segment, with the sixth column
indicates the standard deviation in 2σ. The seventh and eighth columns are the
1
upstream drainage area at the beginning of the segment and the end of the segment,
respectively, in square meters.
Figures 3-12 in the main text are created with data included in these two tables.
Table S1. Knick point data of the rivers analyzed in this study.
Table S2. Concavity values (θ) and river steepness index (ksn) of main trunk segments
of the rivers analyzed in this study.
Figure S1. River longitudinal profiles, SA plots and χ plots of all rivers in this study
except for those shown in Figure 3. The longitudinal profiles of the trunk rivers are
shown in dark blue, and the knickpoints (or knickzones) are shown as red circles.
Yellow crosses show the start and the end of the regression segments along the profile
and the regressed segments are shown in straight blue lines in both the SA plot and the
χ plot. The lithology units where the trunk flows through are shown beneath the long
profile of the trunk, with the abbreviation of the lithology unit names in gray. The
abbreviations are the same as those in Figure 2(b), and each unit is separated by a gray
dashed line that represents only the position of the unit boundary at the surface, without
further interpretations of the underlying structures. Two different smoothing methods are
shown in the SA plot: the results of 250 smoothing window and 10 m resampling are in
gray crosses and the log-bin average results are in red solid squares. Although some
knickpoints appear to be subtle along the longitudinal river profiles, we have identified
them because they show distinctive features either in the χ plot or the SA plot.
Figure S2. The average ksn values of all river groups identified in this study. Error bar
shows one sigma of the average in each group. Group 2-5 shows relatively high ksn
values, whereas groups 1 and 6 show relatively low ksn values.
Figure S3. The relationships between mean elevations (as shown in Figure 10a) and
the ksn values of the most downstream segments of the analyzed rivers (as shown by the
red dots in Figure 10e). The results show that they are moderately correlative, with an
R2 of 0.5.
2