[cig-commits] r11441 - seismo/3D/automeasure/latex
carltape at geodynamics.org
carltape at geodynamics.org
Thu Mar 13 17:39:20 PDT 2008
Author: carltape
Date: 2008-03-13 17:39:20 -0700 (Thu, 13 Mar 2008)
New Revision: 11441
Modified:
seismo/3D/automeasure/latex/REFERENCES.bib
seismo/3D/automeasure/latex/figures_paper.tex
seismo/3D/automeasure/latex/flexwin_paper.pdf
seismo/3D/automeasure/latex/results.tex
Log:
Checking in Min Chen's edits to the windowing paper.
Modified: seismo/3D/automeasure/latex/REFERENCES.bib
===================================================================
--- seismo/3D/automeasure/latex/REFERENCES.bib 2008-03-13 23:56:42 UTC (rev 11440)
+++ seismo/3D/automeasure/latex/REFERENCES.bib 2008-03-14 00:39:20 UTC (rev 11441)
@@ -253,9 +253,8 @@
TITLE = {{Waveform modeling of the slab beneath Japan}},
JOURNAL = {\jgr},
VOLUME = {112},
- YEAR = {2007},
- NOTE = {{doi:10.1029/2006JB004394}}
-}
+ YEAR = 2007,
+ note={doi:10.1029/2006JB004394}}
@article{SmithSandwell97,
AUTHOR = {W. H. F. Smith and D. T. Sandwell},
@@ -717,15 +716,6 @@
YEAR = {2000}
}
- at book{Kern52,
- TITLE = {Earthquakes in Kern County, California During 1952},
- EDITOR = {O. P. Jenkins and G. B. Oakeshott},
- PUBLISHER = {State of California Natural Resources, Division of Mines},
- ADDRESS = {San Francisco, Calif., USA},
- NOTE = {Bulletin 171},
- YEAR = {1955}
-}
-
@article{LSHtomo,
AUTHOR = {G. Lin and P. M. Shearer and E. Hauksson and C. H. Thurber},
JOURNAL = {\jgr},
Modified: seismo/3D/automeasure/latex/figures_paper.tex
===================================================================
--- seismo/3D/automeasure/latex/figures_paper.tex 2008-03-13 23:56:42 UTC (rev 11440)
+++ seismo/3D/automeasure/latex/figures_paper.tex 2008-03-14 00:39:20 UTC (rev 11441)
@@ -261,7 +261,7 @@
%\center
\includegraphics[width=6in]{figures/japan/ERM_II_051502B}
\caption{\label{fg:ERM_II_051502B}
-Window selection results for event 051502B from Table~\ref{tb:events} recorded at station ERM.
+Window selection results for event 051502B from Table~\ref{tb:events} recorded at station ERM ($42.01$\degN, $143.16$\degE, $\Delta=24.83$\deg).
(a)~Event and station map: event is 051502B indicated by the beach ball with the
Harvard CMT focal mechanism, station ERM is marked as red triangles and all the other stations
which recorded this event are marked by grey triangles.
@@ -277,7 +277,7 @@
%\center
\includegraphics[width=6in]{figures/japan/KIS_BO_091502B}
\caption{\label{fg:KIS_BO_091502B}
-Window selection results for event 091502B from Table~\ref{tb:events} recorded at station KIS.
+Window selection results for event 091502B from Table~\ref{tb:events} recorded at station KIS ($33.87$\degN, $135.89$\degE, $\Delta=11.79$\deg).
(a)~Event and station map: event is 091502B indicated by the beach ball with the
Harvard CMT focal mechanism, station KIS is marked as red triangles and all the other stations
which recorded this event are marked by grey triangles.
@@ -292,7 +292,7 @@
%\center
\includegraphics[width=6in]{figures/japan/SHR_BO_20051121536A}
\caption{\label{fg:SHR_BO_20051121536A}
-Window selection results for event 20051121536A from Table~\ref{tb:events} recorded at station SHR.
+Window selection results for event 20051121536A from Table~\ref{tb:events} recorded at station SHR ($44.06$\degN, $144.99$\degE, $\Delta=17.47$\deg).
(a)~Event and station map: event 20051121536A is indicated by the beach ball with the
Harvard CMT focal mechanism, station SHR is marked as red triangles and all the other stations
which recorded this event are marked by grey triangles.
@@ -312,7 +312,6 @@
(a)~Map showing paths to each station with at least one measurement window.
(b)-(d)~Histograms of number of windows as a function of normalised cross-correlation $CC$, time-lag $\tau$ and amplitude ratio $\Delta \ln A$.
(e)-(g)~Record sections of selected windows for the vertical, radial and transverse components.
-The two branches observed on the vertical and radial components correspond to the long-period P-wave arrivals and the Rayleigh-wave arrivals; the one branch on the tangential components corresponds to the wavetrains consisted of the long-period S-wave arrivals and the Love-wave arrivals.
}
\end{figure}
Modified: seismo/3D/automeasure/latex/flexwin_paper.pdf
===================================================================
(Binary files differ)
Modified: seismo/3D/automeasure/latex/results.tex
===================================================================
--- seismo/3D/automeasure/latex/results.tex 2008-03-13 23:56:42 UTC (rev 11440)
+++ seismo/3D/automeasure/latex/results.tex 2008-03-14 00:39:20 UTC (rev 11441)
@@ -181,53 +181,197 @@
\citep{LebedevNolet03} as the background model, with
$P$-wave velocity anomalies added from
a high-resolution Japan $P$-wave model \citep{Zhao94}
-(32--45$^\circ$N, 130--145$^\circ$E
-and down to 500~km) and $S$-wave velocity anomalies
+and $S$-wave velocity anomalies
scaled to $P$ by a factor of 1.5 \citep{Chen07}.
The lateral dimensions of the entire model domain are
44$^\circ$(EW)$\times$33$^\circ$(NS) (108--152$^\circ$E
and 18--51$^\circ$N). Two different crustal
-models are implemented in the model: inside the region of the
-high-resolution model \citep{Zhao94}, the crust model is derived from
+models are implemented in the mesh: inside the region of the
+high-resolution model (32--45$^\circ$N, 130--145$^\circ$E
+and down to 500~km), the crust model is derived from
the arrival time data from local shallow earthquakes \citep{Zhao92};
-outside that region, the crustal model is CRUST2.0.
+outside that region, the crustal model is CRUST2.0 \citep{BassinEtal2000}.
We collected more than $200$ events with $M_w$ from 4.5 to 8 that
occurred between 2000 and 2006. The source location and focal
mechanism are the Harvard centroid-moment tensor (CMT) solutions.
There are total 818 stations from three different networks
-(GSN, F-net and Hi-net) in this area. Amongst which,
-119 stations (GSN and F-net) provide broadband records,
+(GSN, F-net and Hi-net): 119 stations (GSN and F-net)
+provide broadband records,
whereas 699 Hi-net provides only high-frequency records.
We use the one-chunk version of spectral-element code to calculate
the synthetic seismograms accurate at periods of $\sim$6~s and
longer \citep{Chen07}. Data and synthetics are processed in
-two period ranges: 6--30~s for all the records from maximum
-all 818 stations and 24--120~s for the records from 119
-broadband stations.
+two period ranges: 6--30~s for all the records and 24--120~s
+for the broadband records.
-Figures~\ref{fg:ERM_II_051502B}--\ref{fg:091502B_T06_rs} are the examples
-of applying the windowing on the three events listed in
-Table~\ref{tb:example_params}: 051502B (22.4~km), 200511211536A (155~km)
-and 091502B (589.4~km).
+Figure~\ref{fg:ERM_II_051502B}, \ref{fg:KIS_BO_091502B} and
+\ref{fg:SHR_BO_20051121536A} are the examples
+of applying the windowing code on the three-component
+seismograms of three events at
+very different depths (Table~\ref{tb:example_params}):
+051502B, 22.4~km deep, Taiwan; 091502B, 589.4~km deep,
+Northeastern China; 200511211536A, 155~km deep, Kyushu, Japan.
-More text will be added soon to describe the figures.
-Figures~\ref{fg:ERM_II_051502B}
+The windowing code uses different sets of parameters for
+seismograms in $T = 6 - 30$~s and $T = 24 - 120$~s
+(Table~\ref{tb:example_params}). In the period
+range of 24--120~s, the water level is raised after the
+surface-wave arrivals to exclude the later arrivals which are
+not sensitive to the upper mantle structure. In the period
+range of 6--30~s, the water level is raised after the
+$S$-wave arrivals to exclude the surface waves,
+as the current crustal model is not sufficient
+to predict the short-period surface
+waves and the corresponding STA/LTA is also very low.
-Figures~\ref{fg:KIS_BO_091502B}
+Figure~\ref{fg:ERM_II_051502B} shows that, for the shallow event beneath Taiwan
+(051502B) recorded by station ERM, the overall fits of data and synthetics
+are not so good in short-period range (6--30~s)
+(Figure~\ref{fg:ERM_II_051502B}b), but are much
+better at long-period range (24--120s) (Figure~\ref{fg:ERM_II_051502B}c).
+For the seismograms in $T = 6 - 30$~s, the synthetics captures only the major $P$-wave
+arrival on the vertical component (Figure~\ref{fg:ERM_II_051502B}b). While
+for the seismograms in $T = 24 - 120$~s, the windowing code picks not only the
+long-period $P$- and $S$-wave arrivals on three components, but also the
+Rayleigh-wave arrival on vertical and radial component and Love-wave
+arrival on transverse component (Figure~\ref{fg:ERM_II_051502B}c). As the depth sensitivity of the surface waves
+are frequency dependent, the good fits of surface waves
+at long periods (24--120~s) indicate structure deeper than MOHO
+is sufficiently good in the starting model for tomography.
-Figures~\ref{fg:SHR_BO_20051121536A}
+
+Figure~\ref{fg:KIS_BO_091502B} is an example for a deep event (091502B)
+beneath Northeastern China. Compared to the shallow event
+(Figure~\ref{fg:ERM_II_051502B}), the seismograms of this event
+very simple with only two major body-wave arrivals ($P$ and $S$).
+$P$- or $S$-wave windows are picked based on the local level of STA/LTA curve
+and the similarity between the data and synthetics. For example,
+the windowing code did not pick the short-period $S$ arrival
+on the vertical component (Figure~\ref{fg:KIS_BO_091502B}b), as
+the distorted $S$-wave waveform of the data is quite
+different from the synthetics shaped like a simple Gaussian.
+On the other hand, the long-period $S$-wave arrival
+(Figure~\ref{fg:KIS_BO_091502B}c) on the
+same component is selected due to higher data-synthetic
+waveform similarity.
-Figures~\ref{fg:200511211536A_T24_rs}
+The intermediate-depth event (20051121536A) has more phases
+showing up on the seismograms recorded by station SHR
+(Figure~\ref{fg:SHR_BO_20051121536A}).
+For example, on the vertical component of the short-period
+ seismogram (Figure~\ref{fg:SHR_BO_20051121536A}b), $P$ wave
+arrives around 230~s, immediately followed by $pP$ and $sPn$,
+and $S$ wave comes at around 420~s followed by $sS$ around 470~s and
+$PcP$ around 500~s. In the period range of 6--30~s, the windowing
+code chooses the windows for the $P$, $S$ and $sS$ arrivals
+separately on the vertical
+component and $P$ arrival on the radial component.
+In the period range of 24--120~s, the windows of
+two wavepackets are picked in instead on the vertical
+and radial component, $P+pP+sPn$ and $S+sS+PcP$;
+one wavepacket window of $S+sS$ is selected on
+the transverse component.
+Notice that the surface-wave signals of this
+intermediate-depth event are not as obvious as of the shallow event.
-Figures~\ref{fg:200511211536A_T06_rs}
+Figure~\ref{fg:200511211536A_T24_rs} and
+Figure~\ref{fg:200511211536A_T06_rs} show summary plots of the
+window picks for event 200511211536A in two different
+period ranges ($T = 6 - 30$~s and $T = 24 - 120$~s),
+each has a different set of parameters
+(Table~\ref{tb:example_params}). The window record sections
+in both figures highlight the primary phases
+that are picked by the algorithm.
+In the period range of 24--120~s, on the vertical and radial
+component (Figure~\ref{fg:200511211536A_T24_rs}ef), the
+first branch corresponds the wavepacket of $P+pP+sPn$ and the
+second branch corresponds the wavepacket of $S+sS+PcP$;
+the windows on the transverse component capture the
+arrivals of $S+sS$ (Figure~\ref{fg:200511211536A_T24_rs}g).
+The examples of major wavepackets are also shown
+in Figure~\ref{fg:SHR_BO_20051121536A}.
+In the period range of 6--30~s, the windows in the record sections,
+are much narrower compared to the ones in Figure~\ref{fg:200511211536A_T24_rs}. On all three components, the two main branches
+correspond to $P$ and $S$ arrivals. Even on the
+transverse component (Figure~\ref{fg:200511211536A_T06_rs}g),
+the algorithm picks up $P$ arrivals sparsely.
+Of course the number and width of the windows
+for each trace varies with distances.
+We notice that on vertical and radial component
+window record section (Figure~\ref{fg:200511211536A_T06_rs}ef),
+beyond the distance of 14\deg: after the $P$-arrival branch,
+there are two small branches corresponding to $pP$ and $sPn$;
+after the $S$-arrival branch, there is another branch
+corresponding to $sS$. More percentage of measurement windows are
+made in $T = 24 - 120$~s with higher degrees of waveform similarity
+than in $T = 6 - 30$~s, as shown in
+Figure~\ref{fg:200511211536A_T24_rs}b that
+more than two thirds of the total windows have $CC>0.9$, while the
+quite opposite distribution shows in
+Figure~\ref{fg:200511211536A_T06_rs}b.
+$\Delta\tau$ values peak between -5~s to 0~s in both period ranges
+(Figure~\ref{fg:200511211536A_T24_rs}c and
+Figure~\ref{fg:200511211536A_T06_rs}c), indicating that
+the synthetics are slower than the observed records.
+The particularly large peak at -2~s in
+Figure~\ref{fg:200511211536A_T06_rs}c
+of $\Delta\tau$ distribution possibly corresponds
+to the addition of the large number of Hi-net stations for
+short-period range records, and these stations happened
+to be in the same NE direction with respect to this event.
+The $\Delta\ln A$ distribution peaks at $\Delta\ln A\simeq0$
+for $T = 24 - 120$~s (Figure~\ref{fg:200511211536A_T24_rs}d),
+which indicates the amplitude of the synthetics fits the data
+pretty well at long periods. The peak at $\Delta\ln A\simeq-0.3$
+in Figure~\ref{fg:200511211536A_T06_rs}d indicates that on average,
+the synthetics overestimate the amplitude of the
+observed waveforms by 30\%. We cannot know at this stage
+if this anomaly in short-period range is due to an
+overestimation of seismic moment of the events,
+or to an underestimation of the attenuation.
-Figures~\ref{fg:051502B_T06_rs}
-Figures~\ref{fg:091502B_T06_rs}
+Figure~\ref{fg:051502B_T06_rs} and Figure~\ref{fg:091502B_T06_rs}
+show summary plots of the
+window picks for the shallow event (051502B) and deep
+event (091502B) in $T = 6 - 30$~s. Notice the very large numbers of
+measurement windows picked due to the addition of more than 600
+Hi-net stations:
+(Figure~\ref{fg:200511211536A_T06_rs}, Figure~\ref{fg:051502B_T06_rs}
+and Figure~\ref{fg:091502B_T06_rs}): 1356 measurement windows
+for event 200511211536A, 1243 for event 051502B and 1880 for
+event 091502B.
+Comparing all three events at different depth, we can see that
+the degrees of similarity get better with increasing of event
+depth (Figure~\ref{fg:051502B_T06_rs}b,
+Figure~\ref{fg:200511211536A_T06_rs}b and
+Figure~\ref{fg:091502B_T06_rs}b). This implies better estimation
+of mantle structure than the crustal structure
+in the initial model.
+The $\Delta\ln A$ distributions of these three events
+have similar shapes (Figure~\ref{fg:051502B_T06_rs}d,
+Figure~\ref{fg:200511211536A_T06_rs}d and
+Figure~\ref{fg:091502B_T06_rs}d), with peaks in the
+range of -0.5 - -0.3.
+However, the $\Delta\tau$ distributions have very different features
+in Figure~\ref{fg:051502B_T06_rs}c,
+Figure~\ref{fg:200511211536A_T06_rs}c and
+Figure~\ref{fg:091502B_T06_rs}c:
+the shallow event (051502B) has peak $\Delta\tau$ distribution
+at -10~s and another smaller peak at 8~s; the intermediate-depth
+event (200511211536A) has very peaked $\Delta\tau$ distribution
+with a peak at -2s; the deep event(091502B) has very
+distributed $\Delta\tau$ in the range of -2---10~s.
+Again, like what we discussed in the global examples,
+possible explanations for these large average
+time lags include an origin time error,
+and/or an overestimation of the seismic
+velocity at the source location.
+
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\subsection{Southern California scale}
\label{sec:socal}
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