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TABLE 1List of the HVSR measurements, their geographiccoordinates, the frequency of the highest HVSR peak andits amplitude. The last column is the K g coefficient asintroduced by Nakamura (1996).Site Lon Lat Fmax Amax KgCACS 172.5275768 –43.4826609 5.88 2.8 1.3RSMC 172.5628001 –43.5355676 0.94 3.2 10.9N13 172.5705568 –43.5437258 2.00 5.0 12.5N26 172.5777560 –43.5108726 3.88 3.7 3.5N27 172.5818618 –43.5213617 3.19 2.5PPHS 172.6064083 –43.4936198 2.06 5.9 16.9N28 172.6125849 –43.5122464 1.81 3.2 5.7N25 172.6167294 –43.5493591 0.50 3.1 19.2CBGS 172.6199070 –43.5292657 1.38 4.0 11.6CHHC 172.6234361 –43.5368474 1.44 3.5 8.5CMHS 172.6273183 –43.5675024 3.75 4.5 5.4N3 172.6306775 –43.5275045 2.06 4.5 9.8N2 172.6306950 –43.5285730 2.13 5.0 11.7N1 172.6313143 –43.5311002 1.46 4.0 11.0N12 172.6346267 –43.5806096 0.81 3.8 17.8RHES 172.6354074 –43.5235211 2.05 6.0 17.6N30 172.6355683 –43.5310515 1.50 3.9 10.1N32 172.6355845 –43.5284343 1.50 5.0 16.7N31 172.6413124 –43.5309137 1.75 6.0 20.6N14 172.6416583 –43.5213395 2.25 5.0 11.1N24 172.6429684 –43.5476508 0.69 2.5 9.1N4-N5 172.6458412 –43.5257455 1.75 4.3 10.6CCCC 172.6461493 –43.5373261 1.50 4.9 16.0N29 172.6473579 –43.4943542 1.56 5.1 16.7N15 172.6519704 –43.5319409 1.63 3.7 8.4N10 172.6596168 –43.5500570 1.13 4.4 17.1N16 172.6642247 –43.5319177 1.38 2.2 3.5SHLC 172.6651345 –43.5040313 1.50 2.5 4.2N11 172.6752989 –43.5624248 2.63 4.0 6.1PRPC 172.6823280 –43.5281150 1.25 3.4 9.2N17 172.6874653 –43.5401185 1.63 2.8 4.8N6 172.6879189 –43.5015612 1.80 2.2 2.7HPSC 172.7019825 –43.5024466 1.25 1.5 1.8N18 172.7049053 –43.5361145 1.94 2.8 4.0N21 172.7071643 –43.5575285 1.55 5.6 20.2HVSC 172.7082133 –43.5807977 3.56 4.2 5.0N9 172.7228573 –43.6046841 7.44 6.2 5.2N8 172.7233046 –43.6033945 6.06 3.4 1.9N19 172.7291321 –43.5239186 0.38 1.7 7.6N7 172.7313212 –43.5077893 0.31 2.2 15.6N23 172.7360934 –43.5611169 2.00 4.5 10.1N20 172.7433333 –43.5401993 0.50 3.8 28.9N22 172.7604590 –43.5769734 1.25 9.8 76.8RESULTSWe compared our results with the results of Toshinawa et al.(1997) by preparing two maps (Figure 2 and Figure 3) thatshow the frequency of the highest peak in the HVSR curveand the relevant amplitude (Fmax and Amax). It is worth notingthat this highest peak does not always coincide with thesoil fundamental frequency but is closer to the parameterschosen by Toshinawa et al. (1997), for a reason that is evidentif one compares the frequency maps. As mentioned before,Toshinawa et al. did not find any resonance peak in the coastaldune area, while our measurements return values below 1 Hz.It is probable that the older instrumentation, coupled with ashorter-duration sampling time, could not detect low frequencysoil resonance due to a deeper structure. This low frequency isalso often visible moving westward, providing a peak whoseamplitude is generally lower than those in the range above 1Hz. The peaks at frequency >1 Hz appear to be in good agreementwith those reported by Toshinawa et al. (1997), passingfrom 1 Hz below the city center up to 5–6 Hz in the westernmostpart of Christchurch. Our results present quite a differentpicture when the amplitude is taken into account. While theToshinawa et al. (1997) values never exceed 6 and below thecity center HVSR maximum amplitudes are in the range of 2to 3, our measurements top a value of 10 and under the citycenter (or central business district, CBD, as it is often called)the HVSR amplitudes range from 3.5 to 7. It is well known thatHVSR amplitude could be rather sensitive to processing techniques,and a more precise comparison was not possible due tolack of further information from Toshinawa et al. (1997).More detail on our results is given in Figures 4 and 5.Figure 4 shows the clear change in fundamental frequencymoving along longitude, with an increase moving westward.The second plot (Figure 5) shows a site with HVSR that has asingle, low-frequency peak while another site has a similar peakplus another one at higher frequency. It is known that HVSRhas a problem in showing modes higher than the fundamentalone (Parolai and Richwalski 2004), so the two peaks are mostlikely related to a complex stratigraphic situation with tworesonant strata separated by a velocity inversion (Di Giacomoet al. 2005).The second check we performed was the reliability ofthe soil damage index or vulnerability index introduced byNakamura (1996) for use in estimating earthquake damage onthe ground surface. Its distribution should delineate weak areason the ground. It is given as:K g = A g 2 / F g ,where A g is the amplitude corresponding to soil resonance frequencyF g .This coefficient was used in studies aimed at mapping thesoil susceptibility to liquefaction prior to an earthquake (see, e.g.,Beroya et al. 2009 for Laoag City, Philippines), but to our knowledgewas never tested after an earthquake. The fact that the soilfrequencies measured after the 2011 quake are in good agree-920 Seismological Research Letters Volume 82, Number 6 November/December 2011
▲▲Figure 1. Location of the noise measurements taken in Christchurch overlaid on a satellite view from Google Maps. Accelerometricstation CACS and the relevant noise measurement are located northwest of Christchurch airport, out of the upper left corner of theimage.▲▲Figure 2. Map of the frequency of the higher peak in HVSR curves.`Seismological Research Letters Volume 82, Number 6 November/December 2011 921
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Volume 82, Number 6 November/Decemb
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News and Notes (continued)Nominatio
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Preface to the Focused Issue on the
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TABLE 1Peak ground acceleration (PG
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▲▲Figure 2. A) Sketch of the
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▲▲Figure 4. A) Adopted moment r
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▲▲Figure 7. As in Figure 6 but
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▲ ▲ Figure 8. Misfit parameters
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▲ ▲ Figure 10. Spatial variabil
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▲ ▲ Figure 12. Standard spectra
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Quigley, M., R. Van Dissen, P. Vill
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slip on a 59-degree striking fault
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▲▲Figure 4. Convergence of inve
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observations and other source studi
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-42. 5-43. 0-43. 5-44. 0-44. 5-43.2
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“Product CSK © ASI, (ItalianSpac
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TABLE 2Solutions for fault location
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-43.45(A)degrees N-43.50-43.552.52.
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is still a good fit to the horizont
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Coulomb Stress Change Sensitivity d
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mation takes on a larger strike-sli
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P 9.4267BLDU45P 20.1213CASY39P 2.62
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ERMJNUMAJOINUJHJ2CBIJMIDWJOWYHNBTPU
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(A)6.146.13(B)6.246.36Misfit6.156.1
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(A)(B)(C)(D)▲▲Figure 10. The co
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(A)(B)(C)(D)▲▲Figure 12. The co
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Luo, Y., Y. Tan, S. Wei, D. Helmber
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−44˚00' −43˚00'4-Sep-2010Mw 7
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TABLE 1Pairs of SAR imagery used in
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Depth (km)Coulomb Stress Change(bar
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Crippen, R. E. (1992). Measurement
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AlpineFaultHope Fault38 mm/yr0+ +-1
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σ 1dσ 3Nuσ 3CM w 7.1dw 6.2u70°M
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Right-lateral Faults(A) Range Front
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DISCUSSIONThe 2010-2011 Canterbury
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Large Apparent Stresses from the Ca
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▲ ▲ Figure 2. Observed vs. pred
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10Obs SA(1s)AS1AS+SDAB 2006AB+SDSA(
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Fine-scale Relocation of Aftershock
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−43.25°OXZ0 10 20km−43.5°−4
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A’0 km 4 8−43.5°B’B−43.6°
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REFERENCESAvery, H. R., J. B. Berri
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▲ ▲ Figure 2. A) shows three-co
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▲ ▲ Figure 4. Vertical accelera
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0.8PRPC Z0.40Normalized (Max PGA +
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Near-source Strong Ground MotionsOb
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(A)Magnitude, M w876542009 NZdataba
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Scale0.5 g5 seconds▲▲Figure 4.
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(A)(B)Spectral Acc, Sa (g)North/Wes
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Vertical-to-horizontal PGA ratio543
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(A)(B)Station:CCCCSolid:AvgHorizDas
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REFERENCESAagaard, B. T., J. F. Hal
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▲ ▲ Figure 1. Shear-wave veloci
Page 115 and 116: Spectral Acceleration (0.3 s), (g)I
Page 117 and 118: Spectral Acceleration (3 s), (g)In[
Page 119 and 120: TABLE 1Mean (μ LLH ) and standard
Page 121 and 122: Strong Ground Motions and Damage Co
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Page 125 and 126: high, but there were no buildings d
Page 127 and 128: REFERENCES▲▲Figure 8. Heavily d
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Page 131 and 132: (A) (B) (C)▲ ▲ Figure 3. A) Typ
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Page 135 and 136: Case StudyKey ParametersTABLE 1Key
Page 137 and 138: ▲ ▲ Figure 9. Representative bu
Page 139 and 140: Soil Liquefaction Effects in the Ce
Page 141 and 142: ▲ ▲ Figure 2. Representative su
Page 143 and 144: Location of structures illustrated
Page 145 and 146: Shading indicates areaover which pr
Page 147 and 148: 1.8 deg15 cmGround cracking due to
Page 149 and 150: 30 cm17 cm30 cmFoundation beam▲
Page 151 and 152: Comparison of Liquefaction Features
Page 153 and 154: (A)(B)▲▲Figure 2. A) Simplified
Page 155 and 156: (A)Acceleration (Gal)6004002000-200
Page 157 and 158: (A)(B)▲▲Figure 7. Distribution
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Page 161 and 162: (A)(B)▲ ▲ Figure 14. A) Subside
Page 163 and 164: ▲▲Figure 17. A trench in a resi
Page 165: Ambient Noise Measurements followin
Page 169 and 170: ▲▲Figure 5. Site N20 showing HV
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Page 173 and 174: Use of DCP and SASW Tests to Evalua
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Page 177 and 178: (A)(B)▲▲Figure 4. DCP test bein
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Page 181 and 182: where X ~ N(μ X , σ X 2 ) is shor
Page 183 and 184: Using the same critical layers as s
Page 185 and 186: Performance of Levees (Stopbanks) d
Page 187 and 188: ▲▲Figure 3. Typical geometry an
Page 189 and 190: TABLE 1Damage severity categories (
Page 191 and 192: (A)(B)▲▲Figure 6. A) Large sand
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Page 197 and 198: ▲ ▲ Figure 2. Horizontal peak g
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Page 201 and 202: (A)(C)(B)▲▲Figure 5. Ferrymead
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Page 213 and 214: Wednesday, 18 AprilTechnical Sessio
Page 215 and 216: Verification of a Spectral-Element
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EASTERN SECTIONRESEARCH LETTERSReas
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(A)70°N100°W 60°W70°N(B)100°E1
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Mongolia SCRThe presence or absence
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the small horizontal relative motio
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80°100°120°140°EXPLANATIONBorde
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Chang, K. H. (1997). Korean peninsu
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Wheeler, R. L. (2008). Paleoseismic
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A significant outcome of this study
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TABLE 1 (continued)Earthquakes for
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▲▲Figure 2. Earthquakes used in
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Meeting CalendarM E E T I N GC A L
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201 Plaza Professional Bldg. • El
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Seismological Research Letters (SRL
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Christa von Hillebrandt-Andrade, Pr
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