Table summarizing the global seismotectonic classification used in this study (Table S1), and figure showing worldwide Flinn-Engdahl regions, plate boundaries, and seismicity (Figure S3). Figures showing the performance of the current earthquake selection algorithm (Figures S1 and S2) and of the proposed new scheme (Figure S4). Table listing the ShakeMap Atlas-I subset events misclassified by the proposed scheme (Table S2).
Figure S1. Performance of the current Global ShakeMap selection scheme for the Atlas-I subset. (a) Overall results of the analysis. (b) Results for ACR earthquakes, showing how the misclassified events are assigned to the other three earthquake types. For each type results are split in the three depth ranges of Figure 2. Numbers in brackets represent the number of events in all depth ranges misclassified as a specific type. Inset: total distribution of ACR events classification. (c) and (d) Same as (b) for interface and intraslab earthquakes, respectively. SCR events were correctly classified in all cases (32 events), thus no figure is shown for them.
Figure S2. Earthquakes of the Atlas-I subset misclassified by the current Global ShakeMap selection scheme (see Figure S1). Symbols represent the type of earthquake: ACR (squares), interface (triangles), or intraslab (circles). No SCR events were misclassified. Open symbols correspond to the type of event given by the current scheme; filled symbols (smaller size) represent the actual type of earthquake, given by our individual reclassification.
Figure S3. Global map showing FEGRs (Young et al., 1996), plate boundaries (Coffin et al., 1998; Bird, 2003), distributed deformation areas (in grey; Bird, 2003), SCRs (in yellow; Johnston et al., 1994), and seismicity of M 5 and above from PDE catalog (1973-2010) color-coded according to hypocentral depth (orange: 0-35 km; yellow: 35-70 km; green: 70-150 km; blue: 150-300 km; purple: 300-500 km; red: >500 km).
Figure S4. Performance of the new discrimination scheme for the Atlas-I subset. (a) Overall results of the analysis. (b) Results for ANSR earthquakes, showing how the misclassified events are assigned to the other three earthquake types. For each type results are split in the three depth ranges of Figure 2. Numbers in brackets represent the number of events in all depth ranges misclassified as a specific type. Inset: total distribution of ANSR events classification. (c) and (d) Same as (b) for interface and intraslab earthquakes, respectively. Additional earthquake types defined in the new scheme have not been shown separately to ease comparison with Figure S1.
Table S1 contains information on the Flinn-Engdahl Geographical Regions (FEGRs) and the tectonic regime and seismotectonic domain assigned to each region [ASCII Text Comma-Separated Value file; 57 KB].
FEGR_CODE: code number of the FEGR (Young et al., 1996)
FEGR_NAME: name of the FEGR (Young et al., 1996)
TECT_REG: tectonic regime assigned to the FEGR:
SEISM_DOM: seismotectonic domain assigned to the FEGR:
SUB_SCR: absence (0) or presence (1 or 2) of portion(s) inside the FEGR defined as Stable Continental Region (SCR). The SCR portion may be underlain by a slab (2) or not (1). When the whole FEGR is defined as a SCR, this column is marked as '0'.
SUB_REG: absence (0) or presence (1) of portion(s) inside the FEGR defined with a different tectonic regime of that assigned to the FEGR
OBSERVATIONS: relevant information regarding the assigned tectonic regime and seismotectonic domain, the seismicity of the FEGR, or the characteristics of the subregions defined inside the FEGR (catalogs referred in this column are those mentioned in the text)
Table S2 contains the source and scheme parameters of the 31 events from the Atlas-I subset (total of 449 events) that were misclassified by the proposed scheme [ASCII Text Comma-Separated Value file; 8 KB].
DATE & TIME: date and time of the event
REGION: epicentral region of the event
M: magnitude of the event
LAT: epicentral latitude
LON: epicentral longitude
H: hypocentral depth
TYPE: type of earthquake as inferred by the authors:
SCHEME: type of earthquake assigned by the proposed scheme
FEGR: code number of the Flinn-Engdahl Geographical Region where the epicenter lies
TECREG(SD): tectonic regime (and seismotectonic domain) of the FEGR
FM: focal mechanism (NM: normal; RS: reverse; SS: strike-slip; UND: undefined or odd)
P_AZI: P-axis azimuth of the focal mechanism
P_PLG: P-axis plunge of the focal mechanism
SLAB_MOD: slab interface model used (Default: constant-dip model; Hayes: Hayes et al., 2009)
SLAB_STR: slab interface strike at the trench
SLAB_DIP: slab interface dip beneath the epicenter
SLAB_H: slab interface depth beneath the epicenter
FAILURE: reason(s) of the incorrect assignment of earthquake type
Bird, P. (2003). An updated digital model of plate boundaries. Geochem. Geophys. Geosyst. 4, 3, 1027, doi:10.1029/2001GC000252.
Coffin, M.F., L.M. Gahagan, and L.A. Lawver (1998). Present-day plate boundary digital data compilation. Univ. of Texas Inst. For Geophysics Tech. Rep. no. 174. 6 pp.
Hayes, G.P., D.J. Wald, and K. Keranen (2009). Advancing techniques to constrain the geometry of the seismic rupture plane on subduction interfaces a priori: higher-order functional fits. Geochem. Geophys. Geosyst. 10, 9, Q09006, doi:10.1029/2009GC002633.
Johnston, A.C., K.J. Coppersmith, L.R. Kanter, and C.A. Cornell (1994). The earthquakes of stable continental regions. Palo Alto, California, Electric Power Research Institute. 5 vol., 2519 p.
Young, J.B., B.W. Presgrave, H. Aichele, D.A. Wiens, and E.A. Flinn (1996). The Flinn-Engdahl regionalisation scheme: the 1995 revision. Phys. Earth Pl. Int. 96, 4, 221-297. doi:10.1016/0031-9201(96)03141-X.
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