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Fig. 10. Grain-size characteristics of distal Rangitawa Tephra, (a) summary showing particle size distributions for North Island and Chatham Island localities; (b) Rangitawa Stream tephra; (c) Red Bluffs Tephra.

Figure 10 Grain-size characteristics of distal Rangitawa Tephra, (a) summary showing particle size distributions for North Island and Chatham Island localities; (b) Rangitawa Stream tephra; (c) Red Bluffs Tephra.

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This article appeared in a journal published by Elsevier. The attachec copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Provided for non-commercial research and education use. Not for reproduction, distribution or commercial use.
This article appeared in a journal published by Elsevier. The attachec copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Provided for non-commercial research and education use. Not for reproduction, distribution or commercial use.
Fig. 1. (a) Distribution of recovered YTT deposits and location of Toba caldera. Open circles indicate marine cores with YTT identified; black squares show terrestrial YTT localities discussed in this paper and ODP core 758; grey triangle marks Toba caldera. Map adapted from Liu et al. (2006) and Pattan et al. (1999). Location of marine cores with annotated YTT thicknesses, data provided in Table 2 from Ninkovich et al. (1978a, b), Rose and Chesner (1987), Acharyya and Basu (1993), Shane et al. (1995), Pattan et al. (1999, 2001), Bihring et al., (2000), Song et al. (2000), Gasparotto et al. (2000) and Schulz et al. (1998). (b) Toba caldera complex (adapted from Chesner, 1998). Black circles mark YTT sampling locations (see Table 1 for details). Pusikbukit volcano is a prominent post-YTT edifice on the western edge of the lake (Smith et al., 2011). The ~74 ka YTT super-eruption is the youngest of four large eruptions in northern Sumatra, with the earlier three being the ~1.2 Ma Haranggoal Dacite Tuff, ~840 ka Oldest Toba Tuff (OTT), and ~501 ka Middle Toba Tuff (MTT) (Chesner et al., 1991). It formed the 100 x 30 km Toba caldera (Fig. 1; Rose and Chesner, 1987; Chesner, 1998), erupting ~2800 km? (DRE) of rhyolitic magma — making it the largest eruption to have occurred globally during the last 2 Ma (Rose and Chesner, 1987, 1990; Chesner et al., 1991). The minimum mass of the ash fall deposit has previously been estimated as 2 x 10! kg, equivalent to 800 km? DRE, repre- senting ~30% of the total mass of erupted material (Rose and Chesner, 1987). The eruption resulted in deposition of thick ignimbrite sequences proximally (covering up to 30,000 km? of Sumatra; Rose and Chesner, 1987; Bihring et al., 2000) and wide- spread distribution of ash westward over the Indian subcontinent and the Arabian Sea (Schulz et al., 1998; Pattan et al., 1999, 2001), and eastward over the South China Sea (~1500—1800 km NE of Toba; Biihring et al., 2000; Song et al., 2000; Liang et al., 2001; Fig. 1a).
Fig. 1. (a) Distribution of recovered YTT deposits and location of Toba caldera. Open circles indicate marine cores with YTT identified; black squares show terrestrial YTT localities discussed in this paper and ODP core 758; grey triangle marks Toba caldera. Map adapted from Liu et al. (2006) and Pattan et al. (1999). Location of marine cores with annotated YTT thicknesses, data provided in Table 2 from Ninkovich et al. (1978a, b), Rose and Chesner (1987), Acharyya and Basu (1993), Shane et al. (1995), Pattan et al. (1999, 2001), Bihring et al., (2000), Song et al. (2000), Gasparotto et al. (2000) and Schulz et al. (1998). (b) Toba caldera complex (adapted from Chesner, 1998). Black circles mark YTT sampling locations (see Table 1 for details). Pusikbukit volcano is a prominent post-YTT edifice on the western edge of the lake (Smith et al., 2011). The ~74 ka YTT super-eruption is the youngest of four large eruptions in northern Sumatra, with the earlier three being the ~1.2 Ma Haranggoal Dacite Tuff, ~840 ka Oldest Toba Tuff (OTT), and ~501 ka Middle Toba Tuff (MTT) (Chesner et al., 1991). It formed the 100 x 30 km Toba caldera (Fig. 1; Rose and Chesner, 1987; Chesner, 1998), erupting ~2800 km? (DRE) of rhyolitic magma — making it the largest eruption to have occurred globally during the last 2 Ma (Rose and Chesner, 1987, 1990; Chesner et al., 1991). The minimum mass of the ash fall deposit has previously been estimated as 2 x 10! kg, equivalent to 800 km? DRE, repre- senting ~30% of the total mass of erupted material (Rose and Chesner, 1987). The eruption resulted in deposition of thick ignimbrite sequences proximally (covering up to 30,000 km? of Sumatra; Rose and Chesner, 1987; Bihring et al., 2000) and wide- spread distribution of ash westward over the Indian subcontinent and the Arabian Sea (Schulz et al., 1998; Pattan et al., 1999, 2001), and eastward over the South China Sea (~1500—1800 km NE of Toba; Biihring et al., 2000; Song et al., 2000; Liang et al., 2001; Fig. 1a).
YTT thicknesses recorded in India refer to the primary ash thickness, not the over-thickened, reworked deposits; Whakamaru pumice sample SB1119 collected by S. Browr (Brown, 1994); Whakamaru pumices listed as types A, B, C and D, as referred to in text. Localities quoted using WGS84 coordinates. Details of the proximal pumice and distal tephra samples for YTT and Rangitawa. Table 1
YTT thicknesses recorded in India refer to the primary ash thickness, not the over-thickened, reworked deposits; Whakamaru pumice sample SB1119 collected by S. Browr (Brown, 1994); Whakamaru pumices listed as types A, B, C and D, as referred to in text. Localities quoted using WGS84 coordinates. Details of the proximal pumice and distal tephra samples for YTT and Rangitawa. Table 1
Fig. 3. Map of Chatham Island, New Zealand, showing distal Rangitawa Tephra sampling localities and measured thicknesses; Inset shows Chatham Islands location in relation to mainland New Zealand (marked by black box), Rangitawa Stream (R024) and Mount Curl (R025) localities marked by open circles, and Whakamaru caldera marked by grey triangle. Base map from Forsyth et al. (2008). Distal tephra correlatives in the TVZ have been mapped by Manning (1996) using mineralogy and glass chemistry to identify source volcanoes. Localities of deposits referred to here are listed in Table 1, and mapped in Figs. 2 and 3. The type locality is the Ran- gitawa Stream exposure (Site RO24; Fig. 2) near Mt Curl, Wanganui region, North Island, New Zealand (Te Punga, 1952). The most distal on-land exposures of the Rangitawa Tephra are preserved on the
Fig. 3. Map of Chatham Island, New Zealand, showing distal Rangitawa Tephra sampling localities and measured thicknesses; Inset shows Chatham Islands location in relation to mainland New Zealand (marked by black box), Rangitawa Stream (R024) and Mount Curl (R025) localities marked by open circles, and Whakamaru caldera marked by grey triangle. Base map from Forsyth et al. (2008). Distal tephra correlatives in the TVZ have been mapped by Manning (1996) using mineralogy and glass chemistry to identify source volcanoes. Localities of deposits referred to here are listed in Table 1, and mapped in Figs. 2 and 3. The type locality is the Ran- gitawa Stream exposure (Site RO24; Fig. 2) near Mt Curl, Wanganui region, North Island, New Zealand (Te Punga, 1952). The most distal on-land exposures of the Rangitawa Tephra are preserved on the
Fig. 2. Map of New Zealand showing locations and thicknesses of documented Ran- gitawa Tephra (in terrestrial exposures and ocean cores). Whakamaru caldera marked by grey triangle (WH). Samples also marked as follows: RO24 — Rangitawa Stream; RO11 — Red Bluffs, Chathams; ROO6 — Mairangi North, Chathams; and ODP cores marked by black squares. Proximal pumice samples are from the Rangitaiki and Whakamaru ignimbrite units. Refer to Table 3 for location details and references.
Fig. 2. Map of New Zealand showing locations and thicknesses of documented Ran- gitawa Tephra (in terrestrial exposures and ocean cores). Whakamaru caldera marked by grey triangle (WH). Samples also marked as follows: RO24 — Rangitawa Stream; RO11 — Red Bluffs, Chathams; ROO6 — Mairangi North, Chathams; and ODP cores marked by black squares. Proximal pumice samples are from the Rangitaiki and Whakamaru ignimbrite units. Refer to Table 3 for location details and references.
Fig. 4. Field photographs of YTT in India. (a)—(d) Jurreru locality, (e)—(g) Son Valley; (a) basal YTT, scale bar 2 cm; (b) cross-bedding structures 15 cm above basal ash contact; (c) detail of hard pan layer with load structures, scale bar 2 cm; (d) seven hard pan layers visible in reworked YTT sequence; (e) sequence at Ghogara, Middle Son Valley, arrow indicates YTT layer; (f) basal YTT, primary deposit thickness ~4—5 cm; (g) cross-bedding and herringbone structures above basal primary YTT.
Fig. 4. Field photographs of YTT in India. (a)—(d) Jurreru locality, (e)—(g) Son Valley; (a) basal YTT, scale bar 2 cm; (b) cross-bedding structures 15 cm above basal ash contact; (c) detail of hard pan layer with load structures, scale bar 2 cm; (d) seven hard pan layers visible in reworked YTT sequence; (e) sequence at Ghogara, Middle Son Valley, arrow indicates YTT layer; (f) basal YTT, primary deposit thickness ~4—5 cm; (g) cross-bedding and herringbone structures above basal primary YTT.
Fig. 5. Field photographs of Rangitawa Tephra. (a)—(d) Mount Curl and Rangitawa Stream localities, Nth Island, (e)—(g) Chatham Island, New Zealand; (a) Rangitawa Tephra horizon at Mount Curl locality (RO25); (b) 55 cm thick tephra horizon at Rangitawa Stream (R024); (c) detail of the crystal-rich basal tephra, scale bar 1 cm; (d) detail of accretionary lappilli layer at top of tephra horizon; (e) distal Rangitawa Tephra at Red Bluffs (R011), Chatham Island; (f) tephra horizon between peat layers, Kaingaroa, Chatham Island; (g) Kawakawa Tephra horizon at Mairangi North, Chatham Island.
Fig. 5. Field photographs of Rangitawa Tephra. (a)—(d) Mount Curl and Rangitawa Stream localities, Nth Island, (e)—(g) Chatham Island, New Zealand; (a) Rangitawa Tephra horizon at Mount Curl locality (RO25); (b) 55 cm thick tephra horizon at Rangitawa Stream (R024); (c) detail of the crystal-rich basal tephra, scale bar 1 cm; (d) detail of accretionary lappilli layer at top of tephra horizon; (e) distal Rangitawa Tephra at Red Bluffs (R011), Chatham Island; (f) tephra horizon between peat layers, Kaingaroa, Chatham Island; (g) Kawakawa Tephra horizon at Mairangi North, Chatham Island.
Latitude and longitude given in WGS84. Source caldera indicated by bold text. YTT thickness data compiled from the following references — 1: Smith et al., 2011; 2: Acharyya and Basu, 1993; 3: Ninkovich et al., 1978a,b; 4: Song et al., 2000; 5: Westgate et al., 1998; 6: Liang et al., 2001; 7: Pattan et al., 2002. YTT thicknesses used in tephra dispersal modeling, compiled from terrestrial exposures and ocean cores. Table 2
Latitude and longitude given in WGS84. Source caldera indicated by bold text. YTT thickness data compiled from the following references — 1: Smith et al., 2011; 2: Acharyya and Basu, 1993; 3: Ninkovich et al., 1978a,b; 4: Song et al., 2000; 5: Westgate et al., 1998; 6: Liang et al., 2001; 7: Pattan et al., 2002. YTT thicknesses used in tephra dispersal modeling, compiled from terrestrial exposures and ocean cores. Table 2
Latitudes and longitudes in WGS84. Source caldera indicated by bold text. Rangitawa Tephra thickness data compiled from — 1: Holt et al., 2010; 2: Pillans and Kohn, 1981; 3: Pillans et al., 1996; 4: Kohn et al., 1992; 5: Te Punga, 1952; 6: Milne, 1973; 7: Palmer, A., pers. comm.; 8: Lowe et al., 2001; 9: Vucetich et al., 1981; 10: Birrell et al., 1981; 11: Mildenhall and Alloway, 2008; 12: Manning, 1996; 13: Froggatt, 1983; 14: Ninkovich, 1968; 15: Seward, 1974; 16: Watkins and Huang, 1977; 17: Carter et al., 2004; 18: Alloway et al., 2005; 19: Froggatt et al., 1986; 20: Nelson et al., 1985; 21: Nelson, 1988. Rangitawa Tephra identified by glass chemistry, ferromagnesian assemblages, and geochronology. 4 Thickneccec renrecent ectimatec haced on exytranonlatinn fram nearhy Incalities Rangitawa Tephra thicknesses used in tephra dispersal modeling, compiled from terrestrial exposures and ocean cores. Table 3
Latitudes and longitudes in WGS84. Source caldera indicated by bold text. Rangitawa Tephra thickness data compiled from — 1: Holt et al., 2010; 2: Pillans and Kohn, 1981; 3: Pillans et al., 1996; 4: Kohn et al., 1992; 5: Te Punga, 1952; 6: Milne, 1973; 7: Palmer, A., pers. comm.; 8: Lowe et al., 2001; 9: Vucetich et al., 1981; 10: Birrell et al., 1981; 11: Mildenhall and Alloway, 2008; 12: Manning, 1996; 13: Froggatt, 1983; 14: Ninkovich, 1968; 15: Seward, 1974; 16: Watkins and Huang, 1977; 17: Carter et al., 2004; 18: Alloway et al., 2005; 19: Froggatt et al., 1986; 20: Nelson et al., 1985; 21: Nelson, 1988. Rangitawa Tephra identified by glass chemistry, ferromagnesian assemblages, and geochronology. 4 Thickneccec renrecent ectimatec haced on exytranonlatinn fram nearhy Incalities Rangitawa Tephra thicknesses used in tephra dispersal modeling, compiled from terrestrial exposures and ocean cores. Table 3
Numbers are quoted as averages of n analyses, with 1 standard deviation, and results are presented as anhydrous All major elements determined by EPMA at University of Oxford. * H20 by difference. Proximal and distal YTT glass chemistry (by EPMA). Table 4
Numbers are quoted as averages of n analyses, with 1 standard deviation, and results are presented as anhydrous All major elements determined by EPMA at University of Oxford. * H20 by difference. Proximal and distal YTT glass chemistry (by EPMA). Table 4
Fig. 6. Compositions of glass shards at distal sites in India (JWP138, Jurreru, and Middle Son Valley) and YTT in ODP 758, Layer A (Westgate et al., 1998; Smith et al., 2011), compared with proximal data from Sumatra YTT pumice (refer to Table 1 for localities), and MTT (Smith et al., 2011). Trace-element data for distal and proximal YTT samples and MTT are from Smith et al. (2011). Single glass shard data plotted as (a) SiO, vs. KO; (b) CaO vs. FeO!; (c) Rb vs. Sr; and (d) Ba vs. Sr.
Fig. 6. Compositions of glass shards at distal sites in India (JWP138, Jurreru, and Middle Son Valley) and YTT in ODP 758, Layer A (Westgate et al., 1998; Smith et al., 2011), compared with proximal data from Sumatra YTT pumice (refer to Table 1 for localities), and MTT (Smith et al., 2011). Trace-element data for distal and proximal YTT samples and MTT are from Smith et al. (2011). Single glass shard data plotted as (a) SiO, vs. KO; (b) CaO vs. FeO!; (c) Rb vs. Sr; and (d) Ba vs. Sr.
Fig. 7. Compositions of Rangitawa glass shards at distal locality on Chatham Island (RO11) compared with the more proximal Rangitawa Stream locality (RO24), North Island, and proximal pumices from the Rangitaiki and Whakamaru members of the Whakamaru Group Ignimbrites (coded separately in terms of A, B, Cand D magma types). Distal Kawakawa Tephra (ROO6, Chatham Island), and more proximal Kawakawa (from the type Section; Aokautere Ash, Manawatu; Holt et al., 2010) are marked for comparison. K20 may have been slightly affected by alteration (analyses clearly altered are not shown here). Single glass shard data plotted as (a) SiO) vs. Na2O; (b) CaO vs. FeO"; (c) Rb vs. Sr; and (d) Ba vs. Sr.
Fig. 7. Compositions of Rangitawa glass shards at distal locality on Chatham Island (RO11) compared with the more proximal Rangitawa Stream locality (RO24), North Island, and proximal pumices from the Rangitaiki and Whakamaru members of the Whakamaru Group Ignimbrites (coded separately in terms of A, B, Cand D magma types). Distal Kawakawa Tephra (ROO6, Chatham Island), and more proximal Kawakawa (from the type Section; Aokautere Ash, Manawatu; Holt et al., 2010) are marked for comparison. K20 may have been slightly affected by alteration (analyses clearly altered are not shown here). Single glass shard data plotted as (a) SiO) vs. Na2O; (b) CaO vs. FeO"; (c) Rb vs. Sr; and (d) Ba vs. Sr.
Proximal Whakamaru pumice glass chemistry (by EPMA and LA-ICP-MS). All major elements by EPMA; trace elements by LA-ICP-MS. Numbers are quoted as averages of n analyses, with 1 standard deviation. * H20 by difference. Table 5
Proximal Whakamaru pumice glass chemistry (by EPMA and LA-ICP-MS). All major elements by EPMA; trace elements by LA-ICP-MS. Numbers are quoted as averages of n analyses, with 1 standard deviation. * H20 by difference. Table 5
Distal Rangitawa and Kawakawa Tephra glass chemistry (by EPMA and LA-ICP-MS). All major elements by EPMA; trace elements by LA-ICP-MS. Numbers are quoted as averages of n analyses of glass shards, with 1 standard deviation. * H20 by difference. Table 6
Distal Rangitawa and Kawakawa Tephra glass chemistry (by EPMA and LA-ICP-MS). All major elements by EPMA; trace elements by LA-ICP-MS. Numbers are quoted as averages of n analyses of glass shards, with 1 standard deviation. * H20 by difference. Table 6
Grain-size distributions measured on Malvern Mastersizer 2000, data quoted as average of 5 analyses per sample. Mean particle size quoted as geometric mean following methodology of Blott and Pye (2001). Particle fractions are chosen based on ash grain-size classification divisions and health-pertinent fractions. All samples are characterized by a unimodal PSD and are fine skewed. Note that YTT sample JV7-M1 differs from the other YTT basal ash samples, most likely due to sample contamination from the underlying unit or due to reworked material. Selected particle size distribution (PSD) parameters for distal YTT ash and Rangitawa Tephra. Table 7
Grain-size distributions measured on Malvern Mastersizer 2000, data quoted as average of 5 analyses per sample. Mean particle size quoted as geometric mean following methodology of Blott and Pye (2001). Particle fractions are chosen based on ash grain-size classification divisions and health-pertinent fractions. All samples are characterized by a unimodal PSD and are fine skewed. Note that YTT sample JV7-M1 differs from the other YTT basal ash samples, most likely due to sample contamination from the underlying unit or due to reworked material. Selected particle size distribution (PSD) parameters for distal YTT ash and Rangitawa Tephra. Table 7
Fig. 8. Glass chemistry for distal Rangitawa Tephra, showing stratigraphic changes in SiO2, MgO, CaO and Na20; (a) Rangitawa Tephra at Red Bluffs (RO11); Chatham Island; (b) Rangitawa Stream locality (R024), North Island. Locality details provided in Table 1.
Fig. 8. Glass chemistry for distal Rangitawa Tephra, showing stratigraphic changes in SiO2, MgO, CaO and Na20; (a) Rangitawa Tephra at Red Bluffs (RO11); Chatham Island; (b) Rangitawa Stream locality (R024), North Island. Locality details provided in Table 1.
Fig. 9. YTT grain-size characteristics (PSD), all samples from Jurreru Valley, India; (e)—(g) grain-size characteristics for complete reworked YTT sequence (2.5 m thick) a archaeological site JWP138, Jurreru Valley. N.E. Matthews et al. / Quaternary International 258 (2012) 54—79
Fig. 9. YTT grain-size characteristics (PSD), all samples from Jurreru Valley, India; (e)—(g) grain-size characteristics for complete reworked YTT sequence (2.5 m thick) a archaeological site JWP138, Jurreru Valley. N.E. Matthews et al. / Quaternary International 258 (2012) 54—79
Fig. 11. (a) Median grain-size with stratigraphic height for Rangitawa Tephra and basal YTT; Note that both distal YTT and Rangitawa Tephra show similar median grain-size characteristics, and the more proximal RO24 Rangitawa sample shows strong normal grading. Dashed black line at 4.5 cm height marks the upper contact of the YTT primary ash layer, with reworked ash above as indicated by sedimentary structures within the deposit; (b) Median grain-size in terms of fraction of whole deposit with stratigrahic height at Rangitawa Stream locality (R024); all ash is <1000 «um (fine); (c) cumulative frequency plot of YTT grain size; (d) cumulative frequency plot of Rangitawa Tephra grain size.
Fig. 11. (a) Median grain-size with stratigraphic height for Rangitawa Tephra and basal YTT; Note that both distal YTT and Rangitawa Tephra show similar median grain-size characteristics, and the more proximal RO24 Rangitawa sample shows strong normal grading. Dashed black line at 4.5 cm height marks the upper contact of the YTT primary ash layer, with reworked ash above as indicated by sedimentary structures within the deposit; (b) Median grain-size in terms of fraction of whole deposit with stratigrahic height at Rangitawa Stream locality (R024); all ash is <1000 «um (fine); (c) cumulative frequency plot of YTT grain size; (d) cumulative frequency plot of Rangitawa Tephra grain size.
Results of HAZMAP tephra dispersal modeling for Toba and Whakamaru eruptions. YTT model 1 uses all data points (terrestrial and ocean cores) with statistical weighting; YTT model 2 uses all data points with proportional weighting; comparison of these two illustrates uncertainty in the total mass erupted (1500—1900 km? DRE). Rangitawa model 1 uses all data points with statistical weighting (omitting the 25 cm from ODP 591) and assuming a maximum wind intensity of 35 m s~'; Rangitawa model 2 uses the best-fit wind intensity of 42 ms~!. * Maximum column height of 40 km for YTT is the upper limit imposed in the modeling. > Rangitawa volume is underestimated due to ash deposition which also occurred in sectors away from the main SE dispersal axis. Table 8
Results of HAZMAP tephra dispersal modeling for Toba and Whakamaru eruptions. YTT model 1 uses all data points (terrestrial and ocean cores) with statistical weighting; YTT model 2 uses all data points with proportional weighting; comparison of these two illustrates uncertainty in the total mass erupted (1500—1900 km? DRE). Rangitawa model 1 uses all data points with statistical weighting (omitting the 25 cm from ODP 591) and assuming a maximum wind intensity of 35 m s~'; Rangitawa model 2 uses the best-fit wind intensity of 42 ms~!. * Maximum column height of 40 km for YTT is the upper limit imposed in the modeling. > Rangitawa volume is underestimated due to ash deposition which also occurred in sectors away from the main SE dispersal axis. Table 8
Fig. 12. Thickness versus distance data for terrestrial and deep-sea tephra layers in cores of the Toba and Rangitawa Tephra layers, data reported in Tables 2 and 3. Dashed black line shows generalised model for thickness variations in tephra fall deposit with segmentation into four domains as described by Bonadonna et al. (1998), where the proximal segment is formed from deposition of high Reynolds number particles, and the distal segment is formed from deposition of low Reynolds number particles (while the transitional region has a mixture of the two particle populations).
Fig. 12. Thickness versus distance data for terrestrial and deep-sea tephra layers in cores of the Toba and Rangitawa Tephra layers, data reported in Tables 2 and 3. Dashed black line shows generalised model for thickness variations in tephra fall deposit with segmentation into four domains as described by Bonadonna et al. (1998), where the proximal segment is formed from deposition of high Reynolds number particles, and the distal segment is formed from deposition of low Reynolds number particles (while the transitional region has a mixture of the two particle populations).
Fig. 14. Isopach maps for Rangitawa Tephra showing modeled tephra thickness; isopachs labeled in cm of primary ashfall thickness. (a) Model Rangitawa 1, all data points included with equal weighting (with the exception of ODP 591 to the NW of New Zealand, see text); (b) Model Rangitawa 2, with ODP cores to the NE of New Zealand excluded from the simulation, parameters are summarised in Table 8. Input dataset provided in Table 3.
Fig. 14. Isopach maps for Rangitawa Tephra showing modeled tephra thickness; isopachs labeled in cm of primary ashfall thickness. (a) Model Rangitawa 1, all data points included with equal weighting (with the exception of ODP 591 to the NW of New Zealand, see text); (b) Model Rangitawa 2, with ODP cores to the NE of New Zealand excluded from the simulation, parameters are summarised in Table 8. Input dataset provided in Table 3.
Fig. 15. Comparison between the HAZMAP simulation for YTT using the values obtained by best-fit procedure and the field data at each sampling point (where tephra thickness is equivalent to ash loading divided by 11, using a deposit density of 1.1 g cm~3). The equiline (black solid line) represents an ideal line if a perfect agree- ment exists, and the dotted and dashed black lines mark the region between 5 and 1/5 times the observed thickness at each location; (a) YTT modeling results for scenario 1; (b) YTT modeling results for scenario 2 (parameters provided in Table 7).
Fig. 15. Comparison between the HAZMAP simulation for YTT using the values obtained by best-fit procedure and the field data at each sampling point (where tephra thickness is equivalent to ash loading divided by 11, using a deposit density of 1.1 g cm~3). The equiline (black solid line) represents an ideal line if a perfect agree- ment exists, and the dotted and dashed black lines mark the region between 5 and 1/5 times the observed thickness at each location; (a) YTT modeling results for scenario 1; (b) YTT modeling results for scenario 2 (parameters provided in Table 7).
Fig. 16. Comparison between the HAZMAP simulation for Rangitawa Tephra using the values obtained by best-fit procedure and the field data at each sampling point (where tephra thickness is equivalent to ash loading divided by 12, using a deposit density of 1.2 g cm”). The equiline (black solid line) represents an ideal line if a perfect agree- ment exists, and the dotted and dashed lines mark the region between 5 and 1/5 times the observed thickness at each location (parameters provided in Table 7).
Fig. 16. Comparison between the HAZMAP simulation for Rangitawa Tephra using the values obtained by best-fit procedure and the field data at each sampling point (where tephra thickness is equivalent to ash loading divided by 12, using a deposit density of 1.2 g cm”). The equiline (black solid line) represents an ideal line if a perfect agree- ment exists, and the dotted and dashed lines mark the region between 5 and 1/5 times the observed thickness at each location (parameters provided in Table 7).
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