Characterizing the Kathmandu Valley sediment response through strong motion recordings of the 2015 Gorkha earthquake sequence

S. Rajaure, D. Asimaki, E. M. Thompson, S. Hough, S. Martin, J. P. Ampuero, M. R. Dhital, A. Inbal, N. Takai, M. Shigefuji, S. Bijukchhen, M. Ichiyanagi, T. Sasatani, L. Paudel

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

We analyze strong motion records and high-rate GPS measurements of the M 7.8 Gorkha mainshock, M 7.3 Dolakha, and two moderate aftershock events recorded at four stations on the Kathmandu basin sediments, and one on rock-outcrop. Recordings on soil from all four events show systematic amplification relative to the rock site at multiple frequencies in the 0.1–2.5 Hz frequency range, and de-amplification of higher frequencies ( >2.5–10 Hz). The soil-to-rock amplification ratios for the M 7.8 and M 7.3 events have lower amplitude and frequency peaks relative to the ratios of the two moderate events, effects that could be suggestive of nonlinear site response. Further, comparisons to ground motion prediction equations show that 1) both soil and rock mainshock recordings were severely depleted of high frequencies, and 2) the depletion at high frequencies is not present in the aftershocks. These observations indicate that the high frequency deamplification is additionally related to characteristics of the source that are not captured by simplified ground motion prediction equations, and allude to seismic hazard analysis models being revised – possibly by treating isolated high frequency radiation sources separately from long period components to capture large magnitude near-source events such as the 2015 Gorkha mainshock.

Original languageEnglish
Pages (from-to)146-157
Number of pages12
JournalTectonophysics
Volume714-715
DOIs
Publication statusPublished - Sep 13 2017

Fingerprint

strong motion
valleys
sediments
earthquakes
recording
valley
amplification
rocks
soils
aftershock
rock
sediment
ground motion
soil
prediction
seismic hazard
outcrops
predictions
outcrop
radiation sources

All Science Journal Classification (ASJC) codes

  • Earth-Surface Processes
  • Geophysics

Cite this

Rajaure, S., Asimaki, D., Thompson, E. M., Hough, S., Martin, S., Ampuero, J. P., ... Paudel, L. (2017). Characterizing the Kathmandu Valley sediment response through strong motion recordings of the 2015 Gorkha earthquake sequence. Tectonophysics, 714-715, 146-157. https://doi.org/10.1016/j.tecto.2016.09.030

Characterizing the Kathmandu Valley sediment response through strong motion recordings of the 2015 Gorkha earthquake sequence. / Rajaure, S.; Asimaki, D.; Thompson, E. M.; Hough, S.; Martin, S.; Ampuero, J. P.; Dhital, M. R.; Inbal, A.; Takai, N.; Shigefuji, M.; Bijukchhen, S.; Ichiyanagi, M.; Sasatani, T.; Paudel, L.

In: Tectonophysics, Vol. 714-715, 13.09.2017, p. 146-157.

Research output: Contribution to journalArticle

Rajaure, S, Asimaki, D, Thompson, EM, Hough, S, Martin, S, Ampuero, JP, Dhital, MR, Inbal, A, Takai, N, Shigefuji, M, Bijukchhen, S, Ichiyanagi, M, Sasatani, T & Paudel, L 2017, 'Characterizing the Kathmandu Valley sediment response through strong motion recordings of the 2015 Gorkha earthquake sequence', Tectonophysics, vol. 714-715, pp. 146-157. https://doi.org/10.1016/j.tecto.2016.09.030
Rajaure, S. ; Asimaki, D. ; Thompson, E. M. ; Hough, S. ; Martin, S. ; Ampuero, J. P. ; Dhital, M. R. ; Inbal, A. ; Takai, N. ; Shigefuji, M. ; Bijukchhen, S. ; Ichiyanagi, M. ; Sasatani, T. ; Paudel, L. / Characterizing the Kathmandu Valley sediment response through strong motion recordings of the 2015 Gorkha earthquake sequence. In: Tectonophysics. 2017 ; Vol. 714-715. pp. 146-157.
@article{5b172e1a73664415b19bc6507b274f70,
title = "Characterizing the Kathmandu Valley sediment response through strong motion recordings of the 2015 Gorkha earthquake sequence",
abstract = "We analyze strong motion records and high-rate GPS measurements of the M 7.8 Gorkha mainshock, M 7.3 Dolakha, and two moderate aftershock events recorded at four stations on the Kathmandu basin sediments, and one on rock-outcrop. Recordings on soil from all four events show systematic amplification relative to the rock site at multiple frequencies in the 0.1–2.5 Hz frequency range, and de-amplification of higher frequencies ( >2.5–10 Hz). The soil-to-rock amplification ratios for the M 7.8 and M 7.3 events have lower amplitude and frequency peaks relative to the ratios of the two moderate events, effects that could be suggestive of nonlinear site response. Further, comparisons to ground motion prediction equations show that 1) both soil and rock mainshock recordings were severely depleted of high frequencies, and 2) the depletion at high frequencies is not present in the aftershocks. These observations indicate that the high frequency deamplification is additionally related to characteristics of the source that are not captured by simplified ground motion prediction equations, and allude to seismic hazard analysis models being revised – possibly by treating isolated high frequency radiation sources separately from long period components to capture large magnitude near-source events such as the 2015 Gorkha mainshock.",
author = "S. Rajaure and D. Asimaki and Thompson, {E. M.} and S. Hough and S. Martin and Ampuero, {J. P.} and Dhital, {M. R.} and A. Inbal and N. Takai and M. Shigefuji and S. Bijukchhen and M. Ichiyanagi and T. Sasatani and L. Paudel",
year = "2017",
month = "9",
day = "13",
doi = "10.1016/j.tecto.2016.09.030",
language = "English",
volume = "714-715",
pages = "146--157",
journal = "Tectonophysics",
issn = "0040-1951",
publisher = "Elsevier",

}

TY - JOUR

T1 - Characterizing the Kathmandu Valley sediment response through strong motion recordings of the 2015 Gorkha earthquake sequence

AU - Rajaure, S.

AU - Asimaki, D.

AU - Thompson, E. M.

AU - Hough, S.

AU - Martin, S.

AU - Ampuero, J. P.

AU - Dhital, M. R.

AU - Inbal, A.

AU - Takai, N.

AU - Shigefuji, M.

AU - Bijukchhen, S.

AU - Ichiyanagi, M.

AU - Sasatani, T.

AU - Paudel, L.

PY - 2017/9/13

Y1 - 2017/9/13

N2 - We analyze strong motion records and high-rate GPS measurements of the M 7.8 Gorkha mainshock, M 7.3 Dolakha, and two moderate aftershock events recorded at four stations on the Kathmandu basin sediments, and one on rock-outcrop. Recordings on soil from all four events show systematic amplification relative to the rock site at multiple frequencies in the 0.1–2.5 Hz frequency range, and de-amplification of higher frequencies ( >2.5–10 Hz). The soil-to-rock amplification ratios for the M 7.8 and M 7.3 events have lower amplitude and frequency peaks relative to the ratios of the two moderate events, effects that could be suggestive of nonlinear site response. Further, comparisons to ground motion prediction equations show that 1) both soil and rock mainshock recordings were severely depleted of high frequencies, and 2) the depletion at high frequencies is not present in the aftershocks. These observations indicate that the high frequency deamplification is additionally related to characteristics of the source that are not captured by simplified ground motion prediction equations, and allude to seismic hazard analysis models being revised – possibly by treating isolated high frequency radiation sources separately from long period components to capture large magnitude near-source events such as the 2015 Gorkha mainshock.

AB - We analyze strong motion records and high-rate GPS measurements of the M 7.8 Gorkha mainshock, M 7.3 Dolakha, and two moderate aftershock events recorded at four stations on the Kathmandu basin sediments, and one on rock-outcrop. Recordings on soil from all four events show systematic amplification relative to the rock site at multiple frequencies in the 0.1–2.5 Hz frequency range, and de-amplification of higher frequencies ( >2.5–10 Hz). The soil-to-rock amplification ratios for the M 7.8 and M 7.3 events have lower amplitude and frequency peaks relative to the ratios of the two moderate events, effects that could be suggestive of nonlinear site response. Further, comparisons to ground motion prediction equations show that 1) both soil and rock mainshock recordings were severely depleted of high frequencies, and 2) the depletion at high frequencies is not present in the aftershocks. These observations indicate that the high frequency deamplification is additionally related to characteristics of the source that are not captured by simplified ground motion prediction equations, and allude to seismic hazard analysis models being revised – possibly by treating isolated high frequency radiation sources separately from long period components to capture large magnitude near-source events such as the 2015 Gorkha mainshock.

UR - http://www.scopus.com/inward/record.url?scp=84994475499&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84994475499&partnerID=8YFLogxK

U2 - 10.1016/j.tecto.2016.09.030

DO - 10.1016/j.tecto.2016.09.030

M3 - Article

AN - SCOPUS:84994475499

VL - 714-715

SP - 146

EP - 157

JO - Tectonophysics

JF - Tectonophysics

SN - 0040-1951

ER -