BBP Strong Ground Motion Project - Revision history

Maechlin at 06:50, 14 November 2022

2022-11-14T06:50:13Z

Maechlin at 05:49, 14 November 2022

2022-11-14T05:49:48Z

Maechlin at 05:48, 14 November 2022

2022-11-14T05:48:56Z

Maechlin at 05:48, 14 November 2022

2022-11-14T05:48:07Z

Maechlin: /* Southern San Andreas Velocity Model (SSA) (Fang et al) Velocity Model */

2022-11-14T05:36:59Z

Southern San Andreas Velocity Model (SSA) (Fang et al) Velocity Model

Maechlin at 05:34, 14 November 2022

2022-11-14T05:34:37Z

Maechlin at 05:28, 14 November 2022

2022-11-14T05:28:26Z

Maechlin: /* Southern San Andreas Velocity Model (SSA) (Fang et al) Velocity Model */

2022-11-14T05:14:02Z

Southern San Andreas Velocity Model (SSA) (Fang et al) Velocity Model

Maechlin at 05:10, 14 November 2022

2022-11-14T05:10:06Z

Fsilva at 16:18, 25 September 2022

2022-09-25T16:18:49Z

@@ Line 1: / Line 1: @@
-== Southern San Andreas Velocity Model (SSA) (Fang et al)  Velocity Model ==
+== San Jacinto Fault Zone (SJFZ) Velocity Model (Fang et al) ==
-We have renamed this velocity model to the Southern San Andreas model to avoid name collision with PBR (Precarious Balanced Rock) datasets managed by SCEC.
+We have renamed this velocity model to the San Jacinto Fault Zone (SJFZ) model to avoid name collision with PBR (Precarious Balanced Rock) datasets managed by SCEC.
 The original velocity model dataset (a high resolution Fang et al dataset) was defined with 1500m of topography.  To prepare the model for use with the BBP, a series of modifications have been made to the original Fang dataset. Based on information from the model developer, artificial values were used within the original tomography "starting model", including at volume points above the earth's surface but within the simulation volume. The starting model defined artificial values for regions above the topography. These articifical values remained in the model as delivered by Fang et al.
@@ Line 15: / Line 15: @@
 <gallery>
-File:ssa_30m_map.png | SSA Regional of Coverage Map
+File:ssa_30m_map.png | SJFZ Regional of Coverage Map
-File:ssa_30m_vs.png | Vs 30m SSA Model
+File:ssa_30m_vs.png | Vs 30m SJFZ Model
-File:ssa_100m_map.png | SSA Regional of Coverage Map
+File:ssa_100m_map.png | SJFZ Regional of Coverage Map
-File:ssa_100m_vs.png | Vs 100m SSA Model
+File:ssa_100m_vs.png | Vs 100m SJFZ Model
-File:ssa_200m_map.png | SSA Regional of Coverage Map
+File:ssa_200m_map.png | SJFZ Regional of Coverage Map
-File:ssa_200m_vs.png | Vs 200m SSA Model
+File:ssa_200m_vs.png | Vs 200m SJFZ Model
-File:SSA_1000m_depth_map.png | SSA Regional of Coverage Map
+File:SSA_1000m_depth_map.png | SJFZ Regional of Coverage Map
-File:SSA_1000m_depth.png | Vs 1km SSA Model
+File:SSA_1000m_depth.png | Vs 1km SJFZ Model
 </gallery>
 <gallery>
-File:SSA_10km_profile_map.png| Location of SSA Vertical Profile
+File:SSA_10km_profile_map.png| Location of SJFZ Vertical Profile
-File:SSA_10km_profile.png| Vertical Profile for SSA model in well defined region
+File:SSA_10km_profile.png| Vertical Profile for SJFZ model in well defined region
 </gallery>
-A web-based query tool for this model is located here. At this time, this website uses the models old abbreviation (SCPBR). So the correct model to select to view the model is (SCPBR:ely:taper)
+A web-based query tool for this model is located here. At this time, this website uses the models old abbreviation (SCPBR). So the correct model to select to view the model is (SCPBR:ely:taper). We will update this webviewer to use the new Velocity model name and abbreviation soon.
-*[http://moho.scec.org/UCVM_web_test/web/viewer.php SSA Model Test Website]
+*[http://moho.scec.org/UCVM_web_test/web/viewer.php SJFZ Model Test Website]
-== Southern California Plate Boundary (SCPB) Velocity Model ==
+== San Jacinto Fault Zone (SJFZ) Velocity Model ==
-The Fang et al paper defines a Southern California Plate Boundary Velocity model. The max depth is 20 km; the model should be merged with a regional model to have information below that depth but this will require smoothing between models. We are looking at the Vp, Vs models of the Fang et al. (2016) pape. , and also the Fang et al. (GJI, 216, 609–620, doi: 10.1093/gji/ggy458.2019) paper that has better Vs results, and classify the results using K-means clusters as done by Eymold and Jordan (2019). We found that 6 clusters (data types) can account for most of the data. This is preliminary but can help to decide how many distinct 1D velocity models are needed for the region around the SJFZ. More work is required to decide how to merge the results with a regional model.
+The Fang et al paper defines a Southern California Velocity model centered on the San Jacinto Fault Zone. The max depth is 20 km; the model should be merged with a regional model to have information below that depth but this will require smoothing between models. We are looking at the Vp, Vs models of the Fang et al. (2016) pape. , and also the Fang et al. (GJI, 216, 609–620, doi: 10.1093/gji/ggy458.2019) paper that has better Vs results, and classify the results using K-means clusters as done by Eymold and Jordan (2019). We found that 6 clusters (data types) can account for most of the data. This is preliminary but can help to decide how many distinct 1D velocity models are needed for the region around the SJFZ. More work is required to decide how to merge the results with a regional model.
 The horizontal grid spacing in Fang et al. (2106) has an interval of 0.03 deg in both latitude and longitude, which is about 3.3 km. The damage zones results from Allam and Ben-Zion (2012) and also Zigone et al. (2015) are included in the joint inversions of Fang et al. (2016, 2019).  The image above shows the main clusters of velocity models Hao created from the Vp,Vs models of Fang  et al.  We are checking if the fault damage zones are already represented (if not they can be added by increasing the number of clusters).
@@ Line 42: / Line 42: @@
 The model was developed by solving for P-wave velocities (Vp) and earthquake locations on a uniform 1 km-spaced grid using a smoothed 1-D starting model (Fig. 2a) derived from Helmberger et al. (1992). The obtained velocities and event locations are then used iteratively as initial values for inversions on a variable grid that is progressively reduced to a minimum spacing of 100 m in the 4.5 km region on each side (y direction) of the SJFZ. The grid cells in the x and z directions remain uniformly spaced at 1 km. A more detailed discussion of the inversion grid and MATLAB code for generating it are included in Appendix B; a geographical location map for the grid points used is shown in Fig. S1 (above).
-== Prototype Web viewer for SCPB Velocity Model ==
+== Prototype Web viewer for SJFZ Velocity Model ==
 This web viewer can create vertical profiles and cross section plots of the Fang et all SCPBVM. The images below show how the webviewer reproduces the images from Fang et all (2016) Fig. 3 at depths 3km, 7km, 11km, and 16km.
-*[http://moho.scec.org/UCVM_web_test/web/viewer.php SCPBVM Web Viewer]
+*[http://moho.scec.org/UCVM_web_test/web/viewer.php SJFZ Web Viewer]
-== Horizontal Cross Sections Plots of the SCPB Velocity Model ==
+== Horizontal Cross Sections Plots of the SJFZ Velocity Model ==
-This web viewer can create vertical profiles and cross section plots of the Fang et all SCPB Velocity Model. The images below show how the webviewer reproduces the images from Fang et all (2016) Fig. 3 at depths 3km, 7km, 11km, and 16km.
+This web viewer can create vertical profiles and cross section plots of the Fang et all SJFZ Velocity Model. The images below show how the webviewer reproduces the images from Fang et all (2016) Fig. 3 at depths 3km, 7km, 11km, and 16km.
 Full Resolution Model
@@ Line 72: / Line 72: @@
 == Velocity Model Figures ==
 <gallery>
-File:scpbvm_region.png | SCPB Velocity Model Map
+File:scpbvm_region.png | SJFZ Velocity Model Map
 File:FigS1.png | Sensor Net Distribution
 File:velocity_clusters.png| So. Calif Velocity Regions
@@ Line 78: / Line 78: @@
 == Related Papers and Datasets ==
-*[https://g-c662a6.a78b8.36fe.data.globus.org/scpbp/Fang_etal_JGR16.pdf  Fang Southern California Plate Boundary (SCPB) Velocity Model]
+*[https://g-c662a6.a78b8.36fe.data.globus.org/scpbp/Fang_etal_JGR16.pdf  Fang Southern California San Jacinto Fault Zone (SJFZ) Velocity Model]
 *[https://g-c662a6.a78b8.36fe.data.globus.org/scpbp/graves_pitarka2010.pdf BBP Graves and Pitarka Method]
 *[https://g-c662a6.a78b8.36fe.data.globus.org/scpbp/goulet_etal2015.pdf BBP Goulet Validation Paper]
@@ Line 97: / Line 97: @@
 == Model Data File ==
-*[https://g-c662a6.a78b8.36fe.data.globus.org/scpbp/Fang_2016-20220816T055036Z-001.zip Fang SCPB velocity model data files]
+*[https://g-c662a6.a78b8.36fe.data.globus.org/scpbp/Fang_2016-20220816T055036Z-001.zip Fang SJFZ velocity model data files]
 The model data folder has Vp, Vs, and the geographic coordinates. The format is defined as:

@@ Line 18: / Line 18: @@
 File:ssa_30m_vs.png | Vs 30m SSA Model
 File:ssa_100m_map.png | SSA Regional of Coverage Map
-File:SSA_100m_vs.png | Vs 100m SSA Model
+File:ssa_100m_vs.png | Vs 100m SSA Model
 File:ssa_200m_map.png | SSA Regional of Coverage Map
 File:ssa_200m_vs.png | Vs 200m SSA Model

@@ Line 15: / Line 15: @@
 <gallery>
-File:SSA_30m_map.png | SSA Regional of Coverage Map
+File:ssa_30m_map.png | SSA Regional of Coverage Map
-File:SSA_30m_depth.png | Vs 30m SSA Model
+File:ssa_30m_vs.png | Vs 30m SSA Model
-File:SSA_100m_map.png | SSA Regional of Coverage Map
+File:ssa_100m_map.png | SSA Regional of Coverage Map
 File:SSA_100m_vs.png | Vs 100m SSA Model
-File:SSA_200m_map.png | SSA Regional of Coverage Map
+File:ssa_200m_map.png | SSA Regional of Coverage Map
-File:SSA_200m_vs.png | Vs 200m SSA Model
+File:ssa_200m_vs.png | Vs 200m SSA Model
 File:SSA_1000m_depth_map.png | SSA Regional of Coverage Map
 File:SSA_1000m_depth.png | Vs 1km SSA Model

@@ Line 15: / Line 15: @@
 <gallery>
 File:SSA_1000m_depth_map.png | SSA Regional of Coverage Map
 File:SSA_1000m_depth.png | Vs 1km SSA Model
 File:SSA_10km_profile_map.png| Location of SSA Vertical Profile
 File:SSA_10km_profile.png| Vertical Profile for SSA model in well defined region

@@ Line 2: / Line 2: @@
 We have renamed this velocity model to the Southern San Andreas model to avoid name collision with PBR (Precarious Balanced Rock) datasets managed by SCEC.
-The original velocity model dataset (a high resolution Fang et al dataset) was defined with 1500m of topography.
+The original velocity model dataset (a high resolution Fang et al dataset) was defined with 1500m of topography.  To prepare the model for use with the BBP, a series of modifications have been made to the original Fang dataset. Based on information from the model developer, artificial values were used within the original tomography "starting model", including at volume points above the earth's surface but within the simulation volume. The starting model defined artificial values for regions above the topography. These articifical values remained in the model as delivered by Fang et al.
 The first processing stage for preparing the model for use with BBP was to remove the cells in the model with artificial datasets. This was done using a DEM to identify cells above earth surface.
 The next step was to convert the model from a elevation-based model to a depth-based model. After the cells with invalid data were identified and marked as "no data", the topography was removed by pushing the region above sea level down to a 0 depth, to create a flat representation. Region below sea level were pulled up to a 0 depth. This converted the SSA into a depth-based model with the earth surface properties at 0 depth, increasing values below the earth surface.
 The next step was to add the "ely:taper" algorith to modify the Vp and Vs properties in the top 0-700m. This ely:taper has recently been introduced to provide more reasonable velocity profiles in the top 700m. The taper uses a Vs30 value lookup (using Thompson 2022 Vs30 map) and then tapers the Vp and Vs 30 values down to the properties found in the model at 700m.

← Older revision		Revision as of 05:10, 14 November 2022
Line 1:		Line 1:
		+	== Southern San Andreas Velocity Model (SSA) (Fang et al) Velocity Model ==
		+	We have renamed this velocity model to the Southern San Andreas model to avoid name collision with PBR (Precarious Balanced Rock) datasets managed by SCEC.
		+
		+	Our goal has been to converted the Fang et al the high resolution Fang et al dataset to a flat representation that can be converted into a BBP 1D velocity file.
		+
		+	<gallery>
		+	File:scpbvm_region.png \| SCPB Velocity Model Map
		+	File:FigS1.png \| Sensor Net Distribution
		+	File:velocity_clusters.png\| So. Calif Velocity Regions
		+	</gallery>
		+
		+
		+

	== Southern California Plate Boundary (SCPB) Velocity Model ==		== Southern California Plate Boundary (SCPB) Velocity Model ==

@@ Line 86: / Line 86: @@
 Ground motion simulation methods implemented in the SCEC Broadband Platform (BBP) are designed to simulate strong ground motions at levels of engineering interest. The simulation methods have undergone extensive verification and validation efforts involving comparison of simulated results to Ground Motion Prediction Equations (GMPEs) and to the observed ground motions from historical earthquakes. The ground motion simulation methods implemented in the platform propagate seismic waves through a region-specific 1D velocity model, and typically a single 1D velocity model is selected for each validation earthquake. Recently, dense seismic arrays and other methods have produced detailed velocity models for Southern California that often resolve near surface layers better than earlier models. The goal of this study is to use the BBP with multiple 1D velocity models in a region, to study the impact of the different velocity models on the simulated ground motions. We use the Graves and Pitarka ground motion method as implemented in the BBP and large scenario earthquakes on the San Jacinto Fault and the Newport Inglewood Fault consistent with high probability UCERF3 ruptures for Southern California. Initial results in comparison with baseline ground motions using the existing BBP region-specific 1D velocity models will be presented in the meeting.
-== Creating PGA/PGV Maps ==
+== 1D Velocity Models Available on the Broadband Platform ==
 In order to create PGA/PGV maps, we follow the steps below.