Transportation Routes in Soils Susceptible to Ground Failure: New Madrid Seismic Zone

2000 ◽  
Vol 1736 (1) ◽  
pp. 127-133
Author(s):  
Salome Romero ◽  
Glenn J. Rix ◽  
Steven P. French
Keyword(s):  
Remote Sensing ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Data Sources ◽  
New Madrid Seismic Zone ◽  
Seismic Zone ◽  
Remote Sensing Imagery ◽  
Geologic Maps ◽  
Transportation Routes

Geologic deposits susceptible to ground motion amplification under seismic loading in the New Madrid Seismic Zone are delineated using multiple data sources including in situ measurements, geologic maps, and remote-sensing imagery. Soils are classified on the basis of the recommendations from the National Earthquake Hazards Reduction Program, which recommends a classification based on the average shear wave velocity of the geologic material in the upper 30 m. Measurements of shear wave velocity were obtained from Central United States Earthquake Consortium state geologists, the U.S. Geological Survey, and several researchers. However, since this is a predominantly rural area, limited field test data are available. Therefore, several other data sources are introduced including geologic maps and remote-sensing imagery to extrapolate dynamic properties in areas lacking extensive field measurements. Each data source was incorporated into a geographic information system for subsequent analysis. Bridges susceptible to failure from amplification of seismic waves and located on key transportation routes are identified for subsequent risk assessment or seismic retrofitting since the performance of these structures affects disaster planning and rescue efforts and may have severe consequences for the national economy.

Shear-wave velocity of the sedimentary basin in the upper Mississippi embayment using S-to-P converted waves

1996 ◽  
Vol 86 (3) ◽  
pp. 848-856
Author(s):  
Kou-Cheng Chen ◽  
Jer-Ming Chiu ◽  
Yung-Tun Yang
Keyword(s):  
Travel Time ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Sedimentary Basin ◽  
Vertical Component ◽  
Seismic Zone ◽  
Mississippi Embayment ◽  
Upper Mississippi Embayment ◽  
Converted Waves

Abstract From mid-October 1989 to August 1992, 40 three-component PANDA (Portable Array for Numerical Data Acquisition) stations were deployed in the central New Madrid seismic zone. Three-component digital seismograms recorded by the PANDA stations in the region are characterized by (1) the very weak direct S arrivals on the vertical component, which can be identified unambiguously from the two horizontal components, and (2) at least two prominent secondary arrivals between the direct P and S arrivals, one (Sp) dominant on the vertical component and another (Ps) with smaller amplitude on the two horizontal components. Travel-time differences between the Sp and S and between the P and Ps are the same for different earthquakes recorded at the same station but are different at different stations even for the same event. Polarization analyses of three-component seismograms and travel-time measurements confirm the interpretation that these two secondary arrivals are the P-to-S (Ps) and S-to-P (Sp) converted waves that occur at the bottom of the sedimentary basin beneath each station. Since abundant well-log data are available in the upper Mississippi embayment, the thickness of the sediments beneath each seismic station can be estimated. Travel-time differences between the direct and the converted waves can be used to calculate average shear-wave velocity for the sediments beneath each station. The estimated shear-wave velocities of the sediments beneath PANDA stations vary from 0.45 to 0.67 km/sec. The higher shear-wave velocity associated with thicker sediments can be interpreted as a consequence of increasing compaction of unconsolidated sediments due to increasing overburden.

scholarly journals Near surface shear wave velocity in Bucharest, Romania

2008 ◽  
Vol 8 (6) ◽  
pp. 1299-1307 ◽  
Author(s):  
M. von Steht ◽  
B. Jaskolla ◽  
J. R. R. Ritter
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Seismic Velocity ◽  
Seismic Refraction ◽  
Compressional Wave ◽  
Seismic Zone ◽  
Surface Shear ◽  
Near Surface ◽  
Surface Shear Wave

Abstract. Bucharest, the capital of Romania with nearly 2 1/2 million inhabitants, is endangered by the strong earthquakes in the Vrancea seismic zone. To obtain information on the near surface shear-wave velocity Vs structure and to improve the available microzonations we conducted seismic refraction measurements in two parks of the city. There the shallow Vs structure is determined along five profiles, and the compressional-wave velocity (Vp) structure is obtained along one profile. Although the amount of data collected is limited, they offer a reasonable idea about the seismic velocity distribution in these two locations. This knowledge is useful for a city like Bucharest where seismic velocity information so far is sparse and poorly documented. Using sledge-hammer blows on a steel plate and a 24-channel recording unit, we observe clear shear-wave arrivals in a very noisy environment up to a distance of 300 m from the source. The Vp model along profile 1 can be correlated with the known near surface sedimentary layers. Vp increases from 320 m/s near the surface to 1280 m/s above 55–65 m depth. The Vs models along all five profiles are characterized by low Vs (<350 m/s) in the upper 60 m depth and a maximum Vs of about 1000 m/s below this depth. In the upper 30 m the average Vs30 varies from 210 m/s to 290 m/s. The Vp-Vs relations lead to a high Poisson's ratio of 0.45–0.49 in the upper ~60 m depth, which is an indication for water-saturated clayey sediments. Such ground conditions may severely influence the ground motion during strong Vrancea earthquakes.

Flat Dilatometer (DMT), Cone Penetrometer (CPT) and Seismic Cone (SCPT) Evaluation of Select New Madrid Liquefaction Sites

1992 ◽  
Vol 63 (3) ◽  
pp. 357-366
Author(s):  
Roman D. Hryciw
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Horizontal Stress ◽  
Stress Index ◽  
Seismic Zone ◽  
Cone Penetration ◽  
Seismic Shear ◽  
Tip Resistance ◽  
New Madrid

Abstract Cone Penetration (CPT), Flat Dilatometer (DMT) and Seismic Shear Wave Velocity tests were conducted in four regions of the New Madrid seismic zone. Test results are compared to existing liquefaction criteria and to surface evidence of liquefaction (sandblows) during the 1811–1812 events. In general, all three tests confirm the presence of liquefaction-prone strata at locations with evidence of liquefaction. A “sand blow index” (SBI), which accounts for both local and regional sand blow intensity, correlates reasonably well against the minimum values of DMT horizontal stress index, the normalized CPT tip resistance, and the normalized shear wave velocity at each test location. An upperstratum clay also appears to play a significant role in inhibiting sand blow formation. Its thickness also correlates well with the SBI.

VS30 Characterization of Texas, Oklahoma, and Kansas Using the P-Wave Seismogram Method

2017 ◽  
Vol 33 (3) ◽  
pp. 943-961 ◽  
Author(s):  
Georgios Zalachoris ◽  
Ellen M. Rathje ◽  
Jeffrey G. Paine
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Large Scale ◽  
Rock Type ◽  
Geographic Area ◽  
P Wave ◽  
Geologic Maps

The P-wave seismogram method is used to develop estimates of the time averaged shear wave velocity of the upper 30 m ( V S30) at 251 seismic stations in Texas, Oklahoma, and Kansas. Geologic conditions at the sites are documented using large-scale geologic maps. The V S30 values from the P-wave seismogram method agree well with the limited in situ measurements across the study area and correlate well with the mapped geologic units. Compared with the V S30 proxy values assigned to the stations by the Next Generation Attenuation–East (NGA-East) project, the P-wave seismogram method generally produces larger V S30 estimates. These differences are likely due to the fact that very few V S measurements in Texas, Oklahoma, and Kansas were available for use in the development of the NGA-East proxies. Analysis of the P-wave seismogram V S30 values indicates that, in this geographic area, incorporating rock type along with geologic age better distinguishes the average V S30 of these materials than geologic age alone.

Shear-wave splitting and anisotropy in the Charlevoix seismic zone, Quebec, in 1985

1989 ◽  
Vol 26 (12) ◽  
pp. 2691-2696 ◽  
Author(s):  
Goetz G. R. Buchbinder
Keyword(s):  
Active Region ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Crack Density ◽  
Shear Wave Splitting ◽  
Velocity Variation ◽  
Seismic Zone ◽  
Wave Polarization ◽  
Wave Splitting

During the month of October 1985 a second experiment was undertaken in the Charlevoix seismic zone to further test the hypothesis that shear-wave splitting could be observed in a seismically active region. The first experiment had been undertaken in 1984 and yielded only a very limited amount of data. Seismograms recorded by digital three-component seismographs located very close to the epicentres of seven earthquakes showed shear-wave splitting over 15 different paths. The amount of [Formula: see text] wave variation varied from about 24 to 160 ms or from 0.4 to 8.7% of the [Formula: see text] wave velocity. The largest value occurred over the shortest path of about 7 km, for which essentially the whole path may be anisotropic, leading to a crack density (ε) of less than 0.09. For the rest of the data, all with less than 3% shear-wave-velocity variation, ε varies from 0.005 to 0.03, if whole-path anisotropy is assumed. These values of ε are not significantly different from those obtained in 1984. The average azimuth of the initial shear-wave polarization is 37°, also similar to that observed in 1984. All the data in the zone can be explained by the presence of saturated vertical cracks striking 37 °east of north.

scholarly journals Calibrating a new attenuation curve for the Dead Sea region using surface wave dispersion surveys in sites damaged by the 1927 Jericho earthquake

Solid Earth ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 379-390 ◽  
Author(s):  
Yaniv Darvasi ◽  
Amotz Agnon
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Dead Sea ◽  
Attenuation Curve ◽  
Surface Wave Dispersion ◽  
Near Surface ◽  
Moderate Seismicity ◽  
Local Point ◽  
The Dead

Abstract. Instrumental strong motion data are not common around the Dead Sea region. Therefore, calibrating a new attenuation equation is a considerable challenge. However, the Holy Land has a remarkable historical archive, attesting to numerous regional and local earthquakes. Combining the historical record with new seismic measurements will improve the regional equation. On 11 July 1927, a rupture, in the crust in proximity to the northern Dead Sea, generated a moderate 6.2 ML earthquake. Up to 500 people were killed, and extensive destruction was recorded, even as far as 150 km from the focus. We consider local near-surface properties, in particular, the shear-wave velocity, as an amplification factor. Where the shear-wave velocity is low, the seismic intensity far from the focus would likely be greater than expected from a standard attenuation curve. In this work, we used the multichannel analysis of surface waves (MASW) method to estimate seismic wave velocity at anomalous sites in Israel in order to calibrate a new attenuation equation for the Dead Sea region. Our new attenuation equation contains a term which quantifies only lithological effects, while factors such as building quality, foundation depth, topography, earthquake directivity, type of fault, etc. remain out of our scope. Nonetheless, about 60 % of the measured anomalous sites fit expectations; therefore, this new ground-motion prediction equation (GMPE) is statistically better than the old ones. From our local point of view, this is the first time that integration of the 1927 historical data and modern shear-wave velocity profile measurements improved the attenuation equation (sometimes referred to as the attenuation relation) for the Dead Sea region. In the wider context, regions of low-to-moderate seismicity should use macroseismic earthquake data, together with modern measurements, in order to better estimate the peak ground acceleration or the seismic intensities to be caused by future earthquakes. This integration will conceivably lead to a better mitigation of damage from future earthquakes and should improve maps of seismic hazard.

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