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1

Strong-Motion Instrumentation Programs in Taiwan  

E-print Network

by the Central Weather Bureau. 2. Strong-Motion Instrumentation Program by IES 2.1 Strong-Motion Accelerographs64 Strong-Motion Instrumentation Programs in Taiwan T. C. Shin Central Weather Bureau, Taipei- able amounts of resources have been devoted to seismic instru- mentation in general, and strong-motion

Wu, Yih-Min

2

Seismic tomography of Taiwan: Improved constraints from a dense network of strong motion stations  

Microsoft Academic Search

In this study, a large collection of 41,141 S-P times from the untapped records of the Taiwan Strong Motion Instrumentation Program (TSMIP) network is combined with the P and S wave arrival times from the Taiwan Central Weather Bureau Seismic Network (CWBSN) to image the V p and V p \\/V s structures beneath Taiwan. The records from the 680

Yih-Min Wu; Chien-Hsin Chang; Li Zhao; J. Bruce H. Shyu; Yue-Gau Chen; Kerry Sieh; Jean-Philippe Avouac

2007-01-01

3

Seismic tomography of Taiwan: Improved constraints from a dense network of strong motion stations  

Microsoft Academic Search

In this study, a large collection of 41,141 S-P times from the untapped records of the Taiwan Strong Motion Instrumentation Program (TSMIP) network is combined with the P and S wave arrival times from the Taiwan Central Weather Bureau Seismic Network (CWBSN) to image the Vp and Vp\\/Vs structures beneath Taiwan. The records from the 680 TSMIP stations throughout Taiwan

Yih-Min Wu; Chien-Hsin Chang; Li Zhao; J. Bruce H. Shyu; Yue-Gau Chen; Kerry Sieh; Jean-Philippe Avouac

2007-01-01

4

Peak ground motion predictions with empirical site factors using Taiwan Strong Motion Network recordings  

NASA Astrophysics Data System (ADS)

A stochastic method called the random vibration theory (Boore, 1983) has been used to estimate the peak ground motions caused by shallow moderate-to-large earthquakes in the Taiwan area. Adopting Brune's ?-square source spectrum, attenuation models for PGA and PGV were derived from path-dependent parameters which were empirically modeled from about one thousand accelerograms recorded at reference sites mostly located in a mountain area and which have been recognized as rock sites without soil amplification. Consequently, the predicted horizontal peak ground motions at the reference sites, are generally comparable to these observed. A total number of 11,915 accelerograms recorded from 735 free-field stations of the Taiwan Strong Motion Network (TSMN) were used to estimate the site factors by taking the motions from the predictive models as references. Results from soil sites reveal site amplification factors of approximately 2.0˜3.5 for PGA and about 1.3˜ 2.6 for PGV. Finally, as a result of amplitude corrections with those empirical site factors, about 75% of analyzed earthquakes are well constrained in ground motion predictions, having average misfits ranging from 0.30 to 0.50. In addition, two simple indices, R0.57 and R0.38, are proposed in this study to evaluate the validity of intensity map prediction for public information reports. The average percentages of qualified stations for peak acceleration residuals less than R0.57 and R0.38 can reach 75% and 54%, respectively, for most earthquakes. Such a performance would be good enough to produce a faithful intensity map for a moderate scenario event in the Taiwan region.

Chung, J.-K.

2013-09-01

5

Approximate recovery of coseismic deformation from Taiwan strong-motion records  

Microsoft Academic Search

Since 1990, digital strong-motion accelerographs and global positioning system (GPS) instruments have been widely deployed\\u000a in the Taiwan region (Shin et al. 2003; Yu et al. 2001). The 1999 Chi-Chi, Mw 7.6 earthquake and the 2003 Chengkung, Mw 6.8 earthquake were well recorded by both digital accelerographs\\u000a and GPS instruments. These data offer a good opportunity to determine coseismic displacements

Yih-Min Wu; Chien-Fu Wu

2007-01-01

6

Preliminary results from the strong-motion accelerograph array in Taiwan  

SciTech Connect

In May 1978, an international workshop-conference on the design of dense, strong-motion arrays was held at Honolulu. Hawaii with participants from Czechoslovakia, India, Iran, Italy, Japan, Mexico. New Zealand, Spain, Turkey, and the United States. The purpose of this workshop was to bring together experts from around the world to develop concepts for the design of earthquake motion recording instrument systems. These systems would be so arranged as to gather the most information possible for application to advancement of understanding of earthquake shaking behavior and earthquake mechanics in general. The data in turn would provide a better understanding of earthquake-induced ground motion with attendant improvements in the design of safer, motion resisting structures. The instruments agreed upon for such arrays are strong-motion accelerographs that measure strong earthquake shaking in terms of accelerations expressed in percent of the force of gravity (% g). In 1980, an array based on the concepts agreed upon during the Honolulu conference was designed and constructed at a location in northeastern Taiwan where seismic activity frequently occurs. The following report describes this array both in design and performance during the first six months of its operation.

Bolt, B.A. (Univ. of California, Berkely); Penzien, J.; Tsai, Y.B.

1982-01-01

7

Finite-Source Modeling of the 1999 Taiwan (Chi-Chi) Earthquake Derived from a Dense Strong-Motion Network  

Microsoft Academic Search

The 1999 Chi-Chi earthquake (MW 7.6) (20 September 1999, 17:47:15.9 UTC) (located at 23.853 N, 120.816 E, and depth of 7.5 km) inicted severe re- gional scale damage to Taiwan. The strong-motion waveeld was captured by a dense network of stations (with average station spacing of 5 km), which represents the most complete strong-motion dataset to date to use to

Wu-Cheng Chi; Douglas Dreger; Anastasia Kaverina

2004-01-01

8

Improvement on Vp\\/Vs structures and earthquake location using a dense strong motion array in Taiwan  

Microsoft Academic Search

In 1991, the Central Weather Bureau (CWB) undertook the Taiwan Strong Motion Instrumentation Program (TSMIP) deploying 680 digital accelerographs in free-field sites. Because a station spacing of a few kilometers has been achieved (except in the unpopulated high mountain areas). Thus, A large amount and high-quality digital accelerograms were collected from numerous earthquakes occurred in the last fifteen years. These

Y. Wu; C. Chang; L. Zhao

2006-01-01

9

Characteristics of amplitude and duration for near fault strong ground motion from the 1999 Chi-Chi, Taiwan Earthquake  

Microsoft Academic Search

A great number of free-field ground motion records are obtained during the 1999 Chi-Chi, Taiwan, earthquake. Records from 130 near fault free-field stations within 55km to the causative fault surface are used as database, and characteristics of earthquake peak ground acceleration, velocity, displacement and duration are analyzed. According to this study, near fault ground motions are strongly affected by distance

G.-Q Wang; X.-Y Zhou; P.-Z Zhang; H Igel

2002-01-01

10

Preliminary results from the strong-motion accelerograph array in Taiwan  

Microsoft Academic Search

In May 1978, an international workshop-conference on the design of dense, strong-motion arrays was held at Honolulu. Hawaii with participants from Czechoslovakia, India, Iran, Italy, Japan, Mexico. New Zealand, Spain, Turkey, and the United States. The purpose of this workshop was to bring together experts from around the world to develop concepts for the design of earthquake motion recording instrument

B. A. Bolt; J. Penzien; Y. B. Tsai

1982-01-01

11

Some observations on colocated and closely spaced strong ground-motion records of the 1999 Chi-Chi, Taiwan, earthquake  

USGS Publications Warehouse

The digital accelerograph network installed in Taiwan produced a rich set of records from the 20 September 1999 Chi-Chi, Taiwan earthquake (Mw 7.6). Teledyne Geotech model A-800 and A-900A* digital accelerographs were colocated at 22 stations that recorded this event. Comparisons of the amplitudes, frequency content, and baseline offsets show that records from several of the A-800 accelerographs are considerably different than those from the colocated A-900A accelerographs. On this basis, and in view of the more thorough predeployment testing of the newer A-900A instruments, we recommend that the records from the A-800 instruments be used with caution in analyses of the mainshock and aftershocks. At the Hualien seismic station two A-900A and one A-800 instruments were colocated, along with a Global Positioning System instrument. Although the records from the two A-900A instruments are much more similar than those from a colocated A-800 instrument, both three-component records contain unpredictable baseline offsets, which produced completely unrealistic ground displacements derived from the accelerations by double integration, as do many of the strong-motion data from this event; the details of the baseline offsets differ considerably on the two three-component records. There are probably numerous sources of the baseline offsets, including sources external to the instruments, such as tilting or rotation of the ground, and sources internal to the instruments, such as electrical or mechanical hysteresis in the sensors. For the two colocated A-900A records at the Hualien seismic station, however, the differences in the baseline offsets suggest that the principal source is some transient disturbance within the instrument. The baseline offsets generally manifest themselves in the acceleration time series as pulses or steps, either singly or in combination. We find a 0.015-Hz low-cut filter can almost completely eliminate the effects of the baseline offsets, but then information regarding the permanent displacements is lost. The causative mechanisms of the baseline offsets are unknown presently. Hence, it is very difficult to recover the permanent displacements from the modern digital records, although for records close to large earthquakes, the signal-to-noise ratio should theoretically be adequate to obtain ground motions with periods of hundreds of seconds. This study reinforces our conclusion from previous studies that the sources of baseline offsets occurring in digital strong-motion records are very complex and often unpredictable, and that, therefore, it is difficult to remove the baseline effects to maximize the information content of the record. The baseline offsets only affect very long period motions (e.g., >20 sec), however, and therefore are of little or no engineering concern.

Wang, G. -Q.; Boore, D. M.; Igel, H.; Zhou, X. -Y.

2003-01-01

12

Yugoslav strong motion network  

Microsoft Academic Search

Data concerning ground motion and the response of structures during strong earthquakes are necessary for seismic hazard evaluation and the definition of design criteria for structures to be constructed in seismically active zones. The only way to obtain such data is the installation of a strong-motion instrument network. The Yugoslav strong-motion programme was created in 1972 to recover strong-motion response

Vladimir Mihailov

1985-01-01

13

Some Observations on Colocated and Closely Spaced Strong Ground-Motion Records of the 1999 Chi-Chi, Taiwan, Earthquake  

Microsoft Academic Search

Abstract The digital accelerograph network,installed in Taiwan produced a rich set of records from the 20 September 1999 Chi-Chi, Taiwan earthquake (Mw 7.6). Teledyne Geotech model A-800 and A-900A* digital accelerographs were colocated at 22 stations that recorded this event. Comparisons of the amplitudes, frequency content, and baseline offsets show that records from several of the A-800 accelero- graphs are

Guo-quan Wang; David M. Boore; Heiner Igel; Xi-yuan Zhou

2003-01-01

14

GROUND MOTION ASSESSMENT BASED ON WEAK MOTION DATA IN TAIWAN Ground Motion Assessment Based on Weak Motion Data in Taiwan  

NASA Astrophysics Data System (ADS)

In this study, we characterize the scaling of the ground motions for frequencies ranging between 0.25 and 5 Hz, obtaining results for seismic attenuation, geometrical spreading, and source parameters in Taiwan. We regressed this large number of weak-motion data in order to characterize the regional propagation and the absolute source scaling. Stochastic simulations are generated for finite-fault ruptures using the obtained parameters to predict the absolute peaks of the ground acceleration and velocity for several magnitude and distance range, as well as beyond the magnitude range of the weak-motion data set on which they are calculated. The predictions are then compared with recorded strong motion data and empirical ground motion prediction equation obtained for the study region. We showed that our regional parameters, obtained from independent weak-motion database, may be applied for evaluation of ground motion parameters for earthquakes of magnitude up to 7.6.

Akinci, A.; D'Amico, S.; Malagnini, L.

2010-12-01

15

Strong Ground Motion Simulation and Source Modeling of the December 16, 1993 Tapu Earthquake, Taiwan, Using Empirical Green's Function Method  

NASA Astrophysics Data System (ADS)

The Tapu earthquake (ML 5.7) occurred at the southwestern part of Taiwan on December 16, 1993. We examine the source model of this event using the observed seismograms by CWBSN at eight stations surrounding the source area. An objective estimation method is used to obtain the parameters N and C which are needed for the empirical Green's function method by Irikura (1986). This method is called "source spectral ratio fitting method" which gives estimate of seismic moment ratio between a large and a small event and their corner frequencies by fitting the observed source spectral ratio with the ratio of source spectra which obeys the model (Miyake et al., 1999). This method has an advantage of removing site effects in evaluating the parameters. The best source model of the Tapu mainshock in 1993 is estimated by comparing the observed waveforms with the synthetic ones using empirical Green's function method. The size of the asperity is about 2.1 km length along the strike direction by 1.5 km width along the dip direction. The rupture started at the right-bottom of the asperity and extended radially to the left-upper direction.

Huang, H.; Lin, C.

2012-12-01

16

Strong Ground Motion Simulation and Source Modeling of the December 16, 1993 Tapu Earthquake, Taiwan, Using Empirical Green's Function Method  

NASA Astrophysics Data System (ADS)

The Tapu earthquake (ML 5.7) occurred at the southwestern part of Taiwan on December 16, 1993. We examine the source model of this event using the observed seismograms by CWBSN at eight stations surrounding the source area. An objective estimation method is used to obtain the parameters N and C which are needed for the empirical Green's function method by Irikura (1986). This method is called "source spectral ratio fitting method" which gives estimate of seismic moment ratio between a large and a small event and their corner frequencies by fitting the observed source spectral ratio with the ratio of source spectra which obeys the model (Miyake et al., 1999). This method has an advantage of removing site effects in evaluating the parameters. The best source model of the Tapu mainshock in 1993 is estimated by comparing the observed waveforms with the synthetic ones using empirical Green's function method. The size of the asperity is about 2.1 km length along the strike direction by 1.5 km width along the dip direction. The rupture started at the right-bottom of the asperity and extended radially to the left-upper direction.

Huang, H.-C.; Lin, C.-Y.

2012-04-01

17

Vertical and Horizontal Ground-Motion Prediction Equatioin for Taiwan  

Microsoft Academic Search

A suitable attenuation equation can express the characteristics of the strong ground-motion attenuation for a region, and can be used to predict the ground-motion value of a specific site for seismic resistance design. In this study, well processed strong ground-motion data from TSMIP in Taiwan are used to establish horizontal and vertical PGA and SA attenuation equations. A total of

P. Lin; P. Hsieh; C. Cheng; Y. Wu; Y. Chien

2010-01-01

18

Strong-motion seismology  

Microsoft Academic Search

Although this is the first review on this topic to appear in a quadrennial report, the roots of strong-motion seismology extend back to at least 1932, when far-sighted engineers in the Seismological Field Survey of the U. S. Coast and Geodetic Survey installed rugged, fieldworthy instruments designed to make on-scale recordings of large earthquakes (Carder, 1964); these instruments are called

David M. Boore

1983-01-01

19

Site response variation due to the existence of near-field cracks based on strong motion records in the Shi-Wen river valley, southern Taiwan  

NASA Astrophysics Data System (ADS)

Site effect analysis has been applied to investigate soil classification, alluvium depth, and fracture detection, although the majority of previous studies have typically focused only on the response of large-scale single structures. In contrast, we investigated the site effect for small-scale cracks using a case study in southern Taiwan to provide a means of monitoring slope stability or foundation integrity in situ using only an accelerometer. We adopted both the reference site and horizontal-to-vertical spectral ratio methods. We obtained seismographs associated with the typhoon-related development of a crack set (52 m long, 5 m deep) in a steep slope and compared the resonance frequency between two conditions (with and without cracks). Moreover, we divided the seismic waves into P, S, and coda waves and examined the seismic source effect. Our results demonstrate that frequencies of 14.5−17.5 Hz are most sensitive to these cracks, particularly for the E−W component of the P-waves, which coincides with the crack’s strike. Peak ground acceleration, which is controlled by seismic moment and attenuated distance, is another important factor determining the resonance results. Our results demonstrate that the ratio of temporal seismic waves can be used to detect the existence of nearby subsurface cracks.

Wu, Chi-Shin; Yu, Teng-To; Peng, Wen-Fei; Yeh, Yeoin-Tein; Lin, Sih-Siao

2014-10-01

20

Coseismic Fault Slip Rupture from the Joint Inversion of Teleseismic, Local Strong-Motion and CGPS Related to the 2010 Jia-Shian Earthquake in Southwestern Taiwan  

NASA Astrophysics Data System (ADS)

The Jia-Shian earthquake (Mw=6.3) occurred on 04th March 2010 in the southwestern Taiwan. We used the waveforms of teleseismics to identify the strike, dip and rake of focal mechanism are 311/33/37. Furthermore, we explored the strike, dip and rake are 316/40/44 on the first pulse of the teleseismic P wave. We also took account of the Continuous Global Positioning System (CGPS) data for the coseismic offset. The maximum horizontal and vertical (uplift) of coseismic offsets at the surface are 29.8mm± 1.0mm and 30.6mm± 5.1mm, respectively at station GS51. Moreover, the space and time distribution of slip during the coseismic rupture was modeled by the joint inversion, which includes the CGPS coseismic offset, the teleseismic, and near field seismic records. We identified the faults geometry and reconstructed the rupture process of coseismic faults slip. The initial rupture was generated on the northwest - southeast trending fault and propagated to the northeast - southwest trending structure after 5 s of main shock. Their strike, dip and rake are 311/33/37 and 020/25/108, respectively. The average slip of rupture was 20.1 cm, with the maximum slip of 50.4 cm. The rupture of the seismic moment was 4.0 × 10 ^ 25 dyne-cm in 30 s of duration time.The slip rupture constrained the synthetic data quite well, especially for the CGPS coseismic offset. We inferred the Jia-Shian earthquake took place on blind fault and the northeast - southwest trending structure was activated following the rupture on main northwest - southeast trending fault.

Lin, Kuan-Chuan; Delouis, Bertrand; Hu, Jyr-Ching; Nocquet, Jean-Mathieu; Mozziconacci, Laetitia; Bethoux, Nicole

2013-04-01

21

Characterization of Earthquake Strong Ground Motion  

Microsoft Academic Search

— Some underwater landslides are triggered by strong ground motions caused by earthquakes. This paper reviews current concepts and trends in the characterization of strong ground motion. Improved empirical ground motion models have been derived from a strong motion data set that has grown markedly over the past decade. However, these empirical models have a large degree of uncertainty because

P. G. Somerville; R. W. Graves

2003-01-01

22

Technical Note IRAN STRONG MOTION NETWORK  

Microsoft Academic Search

This paper describes current activities in the field of strong motion research in Iran. The seismotectonics and seismological background is explained and current strong motion monitoring in Iran is summarised. The Strong Ground Motion Network of Iran started its activities since 1973, and has recorded more than 4200 accelerograms. The highest ground acceleration recorded in this network was 1g at

H. Mirzaei Alavijeh; E. Farzanegan

23

Tilts in Strong Ground Motion  

Microsoft Academic Search

Most instruments used in seismological practice to record ground motion are pendulum seismographs, velocigraphs or accelerographs. In most cases it is assumed that seismic instruments are only sensitive to the translational motion of the instrument's base. In this study the full equation of pendulum motion including the inputs of rotations and tilts is considered. It is shown that tilting the

Vladimir Graizer

2006-01-01

24

Characterization of Earthquake Strong Ground Motion  

Microsoft Academic Search

\\u000a Some underwater landslides are triggered by strong ground motions caused by earthquakes. This paper reviews current concepts\\u000a and trends in the characterization of strong ground motion. Improved empirical ground motion models have been derived from\\u000a a strong motion data set that has grown markedly over the past decade. However, these empirical models have a large degree\\u000a of uncertainty because the

P. G. Somerville; R. W. Graves

25

Catalog of strong-motion accelerograph records  

Microsoft Academic Search

The National Geophysical Data Center (NGDC) and its collocated World Data Center-A for Solid Earth Geophysics (WDC-A) are responsible for acquiring, archiving, and disseminating strong-motion accelerograph data to meet requirements of the scientific and technical community. The U.S. Geological Survey (USGS) has provided most of the digital data now in the strong-motion archive froms its National Strong-Motion Instrumentation Network. The

J. L. Coffman; S. Godeaux

1985-01-01

26

Seismic switch for strong motion measurement  

DOEpatents

A seismic switching device is described that has an input signal from an existing microseismic station seismometer and a signal from a strong motion measuring instrument. The seismic switch monitors the signal level of the strong motion instrument and passes the seismometer signal to the station data telemetry and recording systems. When the strong motion instrument signal level exceeds a user set threshold level, the seismometer signal is switched out and the strong motion signal is passed to the telemetry system. The amount of time the strong motion signal is passed before switching back to the seismometer signal is user controlled between 1 and 15 seconds. If the threshold level is exceeded during a switch time period, the length of time is extended from that instant by one user set time period. 11 figs.

Harben, P.E.; Rodgers, P.W.; Ewert, D.W.

1995-05-30

27

Seismic switch for strong motion measurement  

DOEpatents

A seismic switching device that has an input signal from an existing microseismic station seismometer and a signal from a strong motion measuring instrument. The seismic switch monitors the signal level of the strong motion instrument and passes the seismometer signal to the station data telemetry and recording systems. When the strong motion instrument signal level exceeds a user set threshold level, the seismometer signal is switched out and the strong motion signal is passed to the telemetry system. The amount of time the strong motion signal is passed before switching back to the seismometer signal is user controlled between 1 and 15 seconds. If the threshold level is exceeded during a switch time period, the length of time is extended from that instant by one user set time period.

Harben, Philip E. (Oakley, CA); Rodgers, Peter W. (Santa Barbara, CA); Ewert, Daniel W. (Patterson, CA)

1995-01-01

28

Magnitude determination using strong ground motion attenuation in earthquake early warning  

E-print Network

Systems) acceleration sensor could be widely used for ground motion monitoring purposes. Thus, we propose acceleration (PGA) larger than 80 Gal (1 Gal = 1.0 cm/s2 ) from 77 earthquakes recorded by the Taiwan Strong characteristics recorded by seismic sensors closest to the earthquake rupture are used to predict strong ground

Wu, Yih-Min

29

Effects of rotation motions on strong-motion data  

NASA Astrophysics Data System (ADS)

Rotation motion and its effects on strong-motion data, in most cases, are much smaller than that of translational motion and have been ignored in most analyses of strong-motion data. However, recent observations from near-fault and/or extreme large ground motions suggest that these effects might be underestimated and quantitative analyses seem to be necessary for improving our understating of these effects. Rotation motion-related effects include centrifugal acceleration, the effects of gravity and effects of the rotation frame. Detailed analyses of these effects based on the observed data are unavailable in the literature. In this study, we develop a numerical algorithm for estimating the effects of rotational motion on the strong-motion data using a set of six-component ground motions and apply it to a set of rotation rate-strong motion velocity data. The data were recorded during a magnitude 6.9 earthquake. The peak value of the derived acceleration and rotation rate of this dataset are about 186 cm/s/s and 0.0026 rad/s. Numerical analyses of data gives time histories of these rotational motion-related effects. Our results show that all the rotation angles are less than 0.01°. The maximum centrifugal acceleration, effect from gravity and effect of the rotation frame are about 0.03 and 0.14 cm/s/s, respectively. Both these two effects are much smaller than the peak acceleration 186 cm/s/s. This result might have been expected because our data are not near-field and wave motions are expected to be nearly plane waves. However, it is worth noticing that the centrifugal acceleration is underestimated and a small rotational effect can cause large waveform difference in acceleration data. The waveform difference before and after the correction for rotational motion can reach 16 cm/s/s (about 10 %).

Chiu, H. C.; Wu, F. J.; Lin, C. J.; Huang, H. C.; Liu, C. C.

2012-10-01

30

A Strong-motion catalog for Indonesia  

NASA Astrophysics Data System (ADS)

Since the Indonesian islands of Sumatra and Java lie adjacent to an active subduction zone and include some of the world's most densely populated areas, the reduction of potential earthquake fatalities through improved building codes and seismic hazard assessments is a high priority. One of the most critical parts of an earthquake hazard assessment is a quantitative description of the level of ground motion generated by an earthquake, also known as Ground Motion Prediction Equations (GMPEs). We have developed a strong ground motion database for of Sumatra and Java. This catalog includes: best-available earthquake catalogue parameters; a compilation of site response information using various techniques; and ground motion parameters commonly used in seismology and engineering applications, such as response spectra. We will show how the database can be used for investigating which published Ground Motion Prediction Equation (GMPE) are appropriate to use for Indonesian earthquake hazard assessment.

Rudyanto, A.; Cummins, P. R.; Ghasemi, H.; Gunawan, I.; Sukanta, N.; Suhardjono, S.

2012-12-01

31

Tilts in strong-ground motion  

NASA Astrophysics Data System (ADS)

Most instruments used in seismological practice to record ground motion are pendulum seismographs, velocigraphs or accelerographs. In most cases it is assumed that seismic instruments are only sensitive to the translational motion of the instrument's base. In this study the full equation of pendulum motion including the inputs of rotations and tilts is considered. It is shown that tilting the accelerograph's base can severely impact its response to the ground motion. The method of tilt evaluation using uncorrected strong-motion accelerograms was first suggested by Graizer (1989), and later tested in a number of laboratory experiments with different strong-motion instruments. The method is based on the difference in the tilt sensitivity of the horizontal and vertical pendulums. The method was applied to a number of strongest records of the Mw 6.7 Northridge earthquake of 1994. Examples are shown when relatively large tilts of up to a few degrees occurred during strong earthquake ground motion. Residual tilt extracted from the strong-motion record at the Pacoima Dam Upper Left Abutment reached 3.1 degrees in N45E direction, and was a result of local earthquake induced tilting due to high amplitude shaking. This value is in agreement with the residual tilt measured using electronic level a few days after the earthquake. The method was applied to the building records from the Northridge earthquake. According to the estimates, residual tilt reached 2.6 degrees on the ground floor of the 12-story Hotel in Ventura. Processing of most of the strongest records of the Northridge earthquake shows that tilts, if happened, were within the error of the method, or less than about 0.5 degree.

Graizer, V.

2006-12-01

32

Catalog of strong-motion accelerograph records  

NASA Astrophysics Data System (ADS)

The National Geophysical Data Center (NGDC) and its collocated World Data Center-A for Solid Earth Geophysics (WDC-A) are responsible for acquiring, archiving, and disseminating strong-motion accelerograph data to meet requirements of the scientific and technical community. The U.S. Geological Survey (USGS) has provided most of the digital data now in the strong-motion archive froms its National Strong-Motion Instrumentation Network. The present catalog contains information on all digital accelerograph records in the archives of NGDC and WDC-A. The date, time, epicenter, magnitude, depth, and intensity of each triggering earthquakes is reported. The recording station, geographic location, date of record, type of accelerograph, component, acceleration, velocity, and displacement is given.

Coffman, J. L.; Godeaux, S.

1985-06-01

33

The Italian Strong Motion Network (RAN)  

NASA Astrophysics Data System (ADS)

A network for the strong motion monitoring of the territory allows recording data that provide an excellent opportunity to study the source, path, and site effects on the ground motions, specifically in near source area, for updating seismic hazard map and consequently construction codes and earthquake resistant design. Strong motion data also help to increase the effective preparation and response to seismic emergencies and the ability of a community to quickly recover from the damages of an earthquake contributes to lower the seismic risk usually measured in term of casualties and economic losses. The Italian network for monitoring the strong movement of the national territory (RAN) is the result of a fruitful cooperation over the last 16 years between the Italian government, the regions and local authorities and now counts more than 500 stations. Over the years, as a priority the DPC has focused mainly on the expansion of the network in terms of the number of measurement points and technological improvement of instrumentation as well as the data transmission system. A data acquisition centre was implemented in which the Antelope software collects, processes and archives, automatically, the data of the RAN and of the external strong motion networks that contribute to the database of the RAN. Recently the DPC has dedicated specific resources to improve the response of the network, in particular, in case of emergency. The efficiency of the network on a daily basis is not less than 95% and temporary networks were installed in the epicentral area within 24 hours after the earthquake and connected to the data acquisition centre in Rome. A fast seismic data analysis is essential to provide useful information to Authorities which make decisions immediately after a strong earthquake occurrence. During a strong earthquake, the modern accelerometers are the only instruments which can provide near source high-quality data that are important both for scientific and for civil protection purposes. Automatic and fast techniques have been developed by the University of Trieste for the automatic real-time strong motion data analysis. These techniques have been installed and customized in the data acquisition centre of the Department of Civil Protection of Italy (DPC) to process the quasi real-time data of the Italian Strong Motion Network (RAN) and to exploit information from RAN stations during seismic emergences for Civil protection purposes. RAN counts more than 500 stations covering all the Italian territory. Two local networks, the Friuli Venezia Giulia Accelerometric Network (RAF), located in NE Italy, and the Irpinia Seismic Network (ISNet), contribute their data into the RAN data acquisition system. The performance of the network and of the fast automatic strong motion data analysis during the Emilia 2012 sequence is analyzed.

Costa, Giovanni; Ammirati, Alfredo; de Nardis, Rita; Filippi, Luisa; Gallo, Antonella; Lavecchia, Giusy; Sirignano, Sebastiano; Zambonelli, Elisa; Nicoletti, Mario

2014-05-01

34

Strong ground motion prediction using virtual earthquakes.  

PubMed

Sedimentary basins increase the damaging effects of earthquakes by trapping and amplifying seismic waves. Simulations of seismic wave propagation in sedimentary basins capture this effect; however, there exists no method to validate these results for earthquakes that have not yet occurred. We present a new approach for ground motion prediction that uses the ambient seismic field. We apply our method to a suite of magnitude 7 scenario earthquakes on the southern San Andreas fault and compare our ground motion predictions with simulations. Both methods find strong amplification and coupling of source and structure effects, but they predict substantially different shaking patterns across the Los Angeles Basin. The virtual earthquake approach provides a new approach for predicting long-period strong ground motion. PMID:24458636

Denolle, M A; Dunham, E M; Prieto, G A; Beroza, G C

2014-01-24

35

Strong motion duration and earthquake magnitude relationships  

SciTech Connect

Earthquake duration is the total time of ground shaking from the arrival of seismic waves until the return to ambient conditions. Much of this time is at relatively low shaking levels which have little effect on seismic structural response and on earthquake damage potential. As a result, a parameter termed ``strong motion duration`` has been defined by a number of investigators to be used for the purpose of evaluating seismic response and assessing the potential for structural damage due to earthquakes. This report presents methods for determining strong motion duration and a time history envelope function appropriate for various evaluation purposes, for earthquake magnitude and distance, and for site soil properties. There are numerous definitions of strong motion duration. For most of these definitions, empirical studies have been completed which relate duration to earthquake magnitude and distance and to site soil properties. Each of these definitions recognizes that only the portion of an earthquake record which has sufficiently high acceleration amplitude, energy content, or some other parameters significantly affects seismic response. Studies have been performed which indicate that the portion of an earthquake record in which the power (average rate of energy input) is maximum correlates most closely with potential damage to stiff nuclear power plant structures. Hence, this report will concentrate on energy based strong motion duration definitions.

Salmon, M.W.; Short, S.A. [EQE International, Inc., San Francisco, CA (United States); Kennedy, R.P. [RPK Structural Mechanics Consulting, Yorba Linda, CA (United States)

1992-06-01

36

A hybrid method of simulating broadband ground motion : A case study of the 2006 Pingtung earthquake, Taiwan  

NASA Astrophysics Data System (ADS)

For the demand of engineering, the time-history of ground motions which consider the reliability and earthquake physical characters have been provided for earthquake resistant design of important building structures. However, the high frequency portion ( > 1 Hz) of near-fault ground motions was restricted by the insufficient resolution of velocity structure. Considering the relative small events which contain path and site effect in waveforms as Green's functions (i.e. empirical Green's function (EGF) method) can resolve the problem of lack of precise velocity structure to replace the path effect evaluation. Alternatively, a stochastic Green's function (SGF) method can be employed when the EGF is unavailable. Further, the low frequency ( < 1 Hz) can be obtained numerically by the Frequency-Wavenumber (FK) method. Thus, broadband frequency strong ground motion can be calculation by a hybrid method that combining a deterministic FK method for the low frequency simulation and the EGF or SGF method for high frequency simulation. The slip models had been investigated from Taiwan dense strong motion and global teleseismic data. Characterizing the slip models derived from the waveform inversion can directly extract the source parameters needed for the ground motion prediction in the EGF method or the SGF method. The nuclear power plant in southern tip of Taiwan was experienced a strong shaking by the 26 December 2006 Pingtung, Taiwan offshore earthquake. The closest strong motion station of the Central Weather Bureau, KAU082, recorded the peak acceleration value (PGA) of 0.24 g. We considered the adjacent stations to be the case study for possibility evaluation of predicting ground motion utilizing the EGF method or SGF method. The possible damage impact toward nuclear power plant for specific sites can be estimated and verified according to the simulation results

Yen, Y.; Ma, K.; Cheng, C.; Shao, K.; Lin, P.

2011-12-01

37

A STUDY ON THE DURATION OF STRONG EARTHQUAKE GROUND MOTION  

Microsoft Academic Search

A simple definition of the duration of strong earthquake ground motion based on the mean-square integral of motion has been presented. It is closely related to that part of the strong motion which contributes significantly to the seismic energy as recorded at a point and to the related spectral amplitudes. Correlations have been established between the duration of strong-motion acceleration,

MI D. TRIFUNAC; A. G. BRADY

1975-01-01

38

The Athens Acropolis Strong Motion Array  

NASA Astrophysics Data System (ADS)

During the last decades, extensive restoration works through a dedicated "Acropolis Restoration Service" (YSMA) take place in the Acropolis, the greatest sanctuary of ancient Athens. Since 2008, a permanent strong motion array was deployed by the Institute of Geodynamics, National Observatory of Athens (NOA-IG) in collaboration with YSMA. Free field installations were decided at sites showing various characteristics, aiming to investigate differences in geotechnical properties as well as the structure response of Parthenon itself. The installation phase is presented, with the techniques used to overcome difficulties (i.e. extreme weather conditions, power and communication limitations, restoration works and visitors) and the special care taken for the specific archaeological site. Furthermore, indicative examples of seismic events recorded by the array are analyzed and the complexity of the hill and the monument is made apparent. Among them, the long distance events of Tohoku, Japan 2010 and Van, Turkey 2011, some regional moderate earthquakes in Greece and some weak earthquakes from the vicinity. Continuous ambient noise monitoring using PQLX software gives some first indicative results, showing a variety of characteristics at installation sites. Finally, further developments and future steps are presented such as: the extension of the array, the integration of seismic data within the GIS platform of YSMA at the site and the use of strong motion records, in conjunction with data from other monitoring systems operating in Acropolis for the study of specific monuments.

Kalogeras, I. S.; Evangelidis, C. P.; Melis, N. S.; Boukouras, K.

2012-04-01

39

Towards Integrated Marmara Strong Motion Network  

NASA Astrophysics Data System (ADS)

Istanbul has a 65% chance of having a magnitude 7 or above earthquake within the next 30 years. As part of the preparations for the future earthquake, strong motion networks have been installed in and around Istanbul. The Marmara Strong Motion Network, operated by the Department of Earthquake Engineering of Kandilli Observatory and Earthquake Research Institute, encompasses permanent systems outlined below. It is envisaged that the networks will be run by a single entity responsible for technical management and maintanence, as well as for data management, archiving and dissemination through dedicated web-based interfaces. • Istanbul Earthquake Rapid Response and Early Warning System - IERREWS (one hundred 18-bit accelerometers for rapid response; ten 24-bit accelerometers for early warning) • IGDA? Gas Shutoff Network (100 accelerometers to be installed in 2010 and integrated with IERREWS) • Structural Monitoring Arrays - Fatih Sultan Mehmet Suspension Bridge (1200m-long suspension bridge across the Bosphorus, five 3-component accelerometers + GPS sensors) - Hagia Sophia Array (1500-year-old historical edifice, 9 accelerometers) - Süleymaniye Mosque Array (450-year-old historical edifice,9 accelerometers) - Fatih Mosque Array (237-year-old historical edifice, 9 accelerometers) - Kanyon Building Array (high-rise office building, 5 accelerometers) - Isbank Tower Array (high-rise office building, 5 accelerometers) - ENRON Array (power generation facility, 4 acelerometers) - Mihrimah Sultan Mosque Array (450-year-old historical edifice,9 accelerometers + tiltmeters, to be installed in 2009) - Sultanahmet Mosque Array, (390-year-old historical edifice, 9 accelerometers + tiltmeters, to be installed in 2009) • Special Arrays - Atakoy Vertical Array (four 3-component accelerometers at 25, 50, 75, and 150 m depths) - Marmara Tube Tunnel (1400 m long submerged tunnel, 128 ch. accelerometric data, 24 ch. strain data, to be installed in 2010) - Air-Force Academy Array (72 ch. dense accelerometric array to be installed in 2010) - Gemlik Array (a dense basin array of 8 stations, to be installed in 2010) The objectives of these systems and networks are: (1) to produce rapid earthquake intensity, damage and loss assessment information after an earthquake (in the case of IERREWS), (2) to monitor conditions of structural systems, (3) to develop real-time data processing, analysis, and damage detection and location tools (in the case of structural networks) after an extreme event, (4) to assess spatial properties of strong ground motion and ground strain, and to characterise basin response (in the case of special arrays), (5) to investigate site response and wave propagation (in the case of vertical array). Ground motion data obtained from these strong motion networks have and are being used for investigations of attenuation, spatial variation (coherence), simulation benchmarking, source modeling, site response, seismic microzonation, system identification and structural model verification and structural health control. In addition to the systems and networks outlined above there are two temporary networks: KIMNET - a dense urban noise and microtremor network consisting of 50 broadband stations expected to be operational in mid 2009, and SOSEWIN - a 20-station, self-organizing structural integrated array at Ataköy in Istanbul.

Durukal, E.; Erdik, M.; Safak, E.; Ansal, A.; Ozel, O.; Alcik, H.; Mert, A.; Kafadar, N.; Korkmaz, A.; Kurtulus, A.

2009-04-01

40

SCEC Broadband Platform Strong Ground Motion Simulations  

NASA Astrophysics Data System (ADS)

The Southern California Earthquake Center (SCEC) Broadband Platform is a collaborative software development project involving SCEC researchers, graduate students, and the SCEC Community Modeling Environment. The goal of the SCEC Broadband Simulation Platform is to generate broadband (0-10 Hz) ground motions for earthquakes using deterministic low-frequency and stochastic high-frequency simulations. SCEC developers have integrated complex scientific modules for rupture generation, low-frequency deterministic seismogram synthesis, high-frequency stochastic seismogram synthesis, and non-linear site effects calculation into a system that supports easy on-demand computation of broadband seismograms. The SCEC Broadband platform has two primary modes of operation, validation mode, and scenario mode. In validation mode, the earthquake modeling software calculates broadband seismograms for one of three earthquakes, Northridge, Loma Prieta, or Landers at sites with observed strong motion data. Then, the platform calculates goodness of fit measurements that quantify how well the model-based broadband seismograms match the observed seismograms for each event. In scenario mode, the user can specify a scenario earthquake and a list of sites and calculate ground motions at each site for the scenario event. In February 2011, SCEC released Broadband Platform 11.2 as an open-source scientific software distribution. Since that time, we have continued development of the platform by adding a new site response module and new goodness of fit measures by Mayhew and Olsen. Along with a source code distribution of the Broadband Platform, we now offer a virtual software image distribution of the platform to support its use on a variety of computing hardware and operating systems.

Kumar, S.; Callaghan, S.; Maechling, P. J.; Olsen, K. B.; Archuleta, R. J.; Somerville, P. G.; Graves, R. W.; Jordan, T. H.; Broadband Platform Working Group

2011-12-01

41

Motion and evolution of the Chaochou Fault, Southern Taiwan  

E-print Network

The Chaochou Fault (CCF) is both an important lithologic boundary and a significant topographic feature in the Taiwan orogenic belt. It is the geologic boundary between the Slate Belt to the east, and the Western Foothills to the west. Although...

Hassler, Lauren E.

2005-11-01

42

Evolution of accelerographs, data processing, strong motion arrays and amplitude and spatial resolution in recording strong earthquake motion  

Microsoft Academic Search

This paper presents a review of the advances in strong motion recording since the early 1930s, based mostly on the experiences in the United States. A particular emphasis is placed on the amplitude and spatial resolution of recording, which both must be ‘adequate’ to capture the nature of strong earthquake ground motion and response of structures. The first strong motion

M. D. Trifunac; M. I. Todorovska

2001-01-01

43

Modeling and synthesis of strong ground motion  

Microsoft Academic Search

Success of earthquake resistant design practices critically depends on how accurately the future ground motion can be determined at a desired site. But very limited recorded data are available about ground motion in India for engineers to rely upon. To identify the needs of engineers, under such circumstances, in estimating ground motion time histories, this article presents a detailed review

S. T. G. Raghu Kanth

2008-01-01

44

Synthetic Strong Ground Motion Validation and Prediction  

Microsoft Academic Search

In this paper, I first validate a ground motion simulation procedure against ground motion observation from the Imperial Valley, Loma Prieta, Landers, Northridge, Kobe, and Kocaeli earthquakes. The ground motion simulation procedure follows Zeng et al. (1994) using a composite source model. In that model, the source is taken as a superposition of circular subevents with a constant stress drop.

Y. Zeng

2003-01-01

45

Modeling and synthesis of strong ground motion  

Microsoft Academic Search

Success of earthquake resistant design practices critically depends on how accurately the future ground motion can be determined\\u000a at a desired site. But very limited recorded data are available about ground motion in India for engineers to rely upon. To\\u000a identify the needs of engineers, under such circumstances, in estimating ground motion time histories, this article presents\\u000a a detailed review

S. T. G. Raghu Kanth

2008-01-01

46

Explosion Source Strong Ground Motions in the Mississippi Embayment  

Microsoft Academic Search

Two strong-motion arrays were deployed for the October 2002 Embay- ment Seismic Excitation Experiment to study the spatial variation of strong ground motions in the deep, unconsolidated sediments of the Mississippi embayment because there are no comparable strong-motion data from natural earthquakes in the area. Each linear array consisted of eight three-component K2 accelerographs spaced 15 m apart situated 1.2

Charles A. Langston; Paul Bodin; Christine Powell; Mitch Withers; Steve Horton; Walter Mooney

2006-01-01

47

Site classification of Turkish national strong-motion stations  

Microsoft Academic Search

Since 1973, the General Directorate of Disaster Affairs of Turkey has deployed several strong-motion accelerographs at selected sites. Within the framework of the project entitled Compilation of National Strong Ground Motion Database in Accordance with International Standards, site conditions were investigated within the upper 30-m depth by surface seismic and standard penetration tests. Preliminary characterization of the sites is made

M. Abdullah Sandikkaya; Mustafa Tolga Yilmaz; B. Sadik Bakir; Özdogan Yilmaz

2010-01-01

48

Turkish strong ground motion data acquisition and analysis  

Microsoft Academic Search

The installation of a strong-motion network in Turkey was initiated in 1973 under the sponsorship of the Earthquake Research Institute. Today, 61 accelerographs and 40 seismoscope stations have been installed along the most active seismic zones, namely the North Anatolian zone and in the graben systems of western Anatolia. All the strong ground motion records, which were obtained during the

Ref'an Ates

1985-01-01

49

Taiwan.  

PubMed

Attention in this discussion of Taiwan is directed to the following: geography; the people -- education, languages, religions, and cultural background; history; administration; political conditions; the economy; defense; foreign relations; and relations between the US and Taiwan. In 1987 the population was estimated to be 19.7 million with an annual growth rate of 1.07%. The infant mortality rate in 1986 was 0.7% with a life expectancy of 70.8 for men and 75.8 for women. Taipei, which continues its claim of sovereignty over all of China in the name of the "Republic of China," exercises control only over the island of Taiwan, the Penghu Islands, and about 20 offshore islands, most near the China mainland. Most native Taiwanese speak a variant of the Amoy (Hokkien) dialect of Southern Fujian. The predominant religion is a combination of Buddhism and Taoism. Chinese sources show migration to Taiwan began as early as A.D. 500. Dutch traders 1st claimed the island in 1624 as a base for Dutch commerce with Japan and the China coast. The 1st major influx of migrants from the Chinese mainland came during the Dutch period. In 1664, a Chinese fleet led by the Ming loyalist Zheng Chenggong retreated from the mainland and occupied Taiwan. Zheng expelled the Dutch and established Taiwan as a base in his attempt to restore the Ming Dynasty. After his death in 1683, his successors submitted to Manchu control. Manchu China ruled Taiwan as a frontier district until it was declared a separate Chinese province in 1886. The authorities in Taipei claim to be the government of all China, including Taiwan. When President Chiang Ching-kuo died in 1988, he was succeeded by Vice President Lee Teng-hui, who had been elected along with Chiang by the National Assembly to a 6-year term. Until 1986, Taiwan's political system was effectively 1 party. Before elections in 1986, many "nonpartisans" grouped together to form Taiwan's 1st new political party in over 4 decades -- the Democratic Progressive Party. Friction between mainlanders and native Taiwanese continues to be a problem, but it has abated with time and the gradual melding of the 2 Chinese communities. Taiwan has changed from an agricultural to an industrialized economy over the past 30 years. During 1973-82, the gross domestic product rose at an annual average of 9.5% in real terms. President Carter signed into law on April 10, 1979, the Taiwan Relations Act, which created domestic legal authority for the conduct of unofficial relations with Taiwan. PMID:12177975

1988-03-01

50

Towards an integrated European strong motion data distribution  

NASA Astrophysics Data System (ADS)

Recent decades have seen a significant increase in the quality and quantity of strong motion data collected in Europe, as dense and often real-time and continuously monitored broadband strong motion networks have been constructed in many nations. There has been a concurrent increase in demand for access to strong motion data not only from researchers for engineering and seismological studies, but also from civil authorities and seismic networks for the rapid assessment of ground motion and shaking intensity following significant earthquakes (e.g. ShakeMaps). Aside from a few notable exceptions on the national scale, databases providing access to strong motion data has not appeared to keep pace with these developments. In the framework of the EC infrastructure project NERA (2010 - 2014), that integrates key research infrastructures in Europe for monitoring earthquakes and assessing their hazard and risk, the network activity NA3 deals with the networking of acceleration networks and SM data. Within the NA3 activity two infrastructures are being constructed: i) a Rapid Response Strong Motion (RRSM) database, that following a strong event, automatically parameterises all available on-scale waveform data within the European Integrated waveform Data Archives (EIDA) and makes the waveforms easily available to the seismological community within minutes of an event; and ii) a European Strong Motion (ESM) database of accelerometric records, with associated metadata relevant to earthquake engineering and seismology research communities, using standard, manual processing that reflects the state of the art and research needs in these fields. These two separate repositories form the core infrastructures being built to distribute strong motion data in Europe in order to guarantee rapid and long-term availability of high quality waveform data to both the international scientific community and the hazard mitigation communities. These infrastructures will provide the access to strong motion data in an eventual EPOS seismological service. A working group on Strong Motion data is being created at ORFEUS in 2013. This body, consisting of experts in strong motion data collection, processing and research from across Europe, will provide the umbrella organisation that will 1) have the political clout to negotiate data sharing agreements with strong motion data providers and 2) manage the software during a transition from the end of NERA to the EPOS community. We expect the community providing data to the RRSM and ESM will gradually grow, under the supervision of ORFEUS, and eventually include strong motion data from networks from all European countries that can have an open data policy.

Luzi, Lucia; Clinton, John; Cauzzi, Carlo; Puglia, Rodolfo; Michelini, Alberto; Van Eck, Torild; Sleeman, Reinhoud; Akkar, Sinan

2013-04-01

51

Earthquake strong-motion instrumentation at Lawrence Livermore National Laboratory  

Microsoft Academic Search

A network of strong-motion accelerograph was installed at the Lawrence Livermore National Laboratory (LLNL) as part of site seismic safety program. The network has two objectives: to provide quantitative information on the severity of ground shaking for the assessment of structural effects at LLNL following an earthquake, and to provide data for analyses of the free-field ground motion and the

A. F. Shakal; R. C. Murray

1981-01-01

52

DETERMINATION OF LOCAL MAGNITUDE, ML, FROM STRONG MOTION ACCELEROGRAMS  

Microsoft Academic Search

A technique is presented for determination of local magnitude, ML, from strong-motion accelerograms. The accelerograph records are used as an accel- eration input to the equation of motion of the Wood-Anderson torsion seismo- graph to produce a synthetic seismogram which is then read in the standard manner. When applied to 14 records from the San Fernando earthquake, the resulting ML

HIROO KANAMORI; PAUL C. JENNINGS

1978-01-01

53

Processing of strong-motion accelerograms: needs, options and consequences  

Microsoft Academic Search

Recordings from strong-motion accelerographs are of fundamental importance in earthquake engineering, forming the basis for all characterizations of ground shaking employed for seismic design. The recordings, particularly those from analog instruments, invariably contain noise that can mask and distort the ground-motion signal at both high and low frequencies. For any application of recorded accelerograms in engineering seismology or earthquake engineering,

David M. Boore; Julian J. Bommer

2005-01-01

54

Strong Ground Motion from the Michoacan, Mexico, Earthquake  

Microsoft Academic Search

The network of strong motion accelerographs in Mexico includes instruments that were installed, under an international cooperative research program, in sites selected for the high potential of a large earthquake. The 19 September 1985 earthquake (magnitude 8.1) occurred in a seismic gap where an earthquake was expected. As a result, there is an excellent description of the ground motions that

J. G. Anderson; P. Bodin; J. N. Brune; J. Prince; S. K. Singh; R. Quaas; M. Onate

1986-01-01

55

Site classification of Turkish national strong-motion stations  

Microsoft Academic Search

Since 1973, the General Directorate of Disaster Affairs of Turkey has deployed several strong-motion accelerographs at selected\\u000a sites. Within the framework of the project entitled Compilation of National Strong Ground Motion Database in Accordance with International Standards, site conditions were investigated within the upper 30-m depth by surface seismic and standard penetration tests. Preliminary\\u000a characterization of the sites is made

M. Abdullah Sand?kkaya; Mustafa Tolga Y?lmaz; B. Sad?k Bak?r; Özdo?an Y?lmaz

2010-01-01

56

Earthquake strong-motion instrumentation at Lawrence Livermore National Laboratory  

NASA Astrophysics Data System (ADS)

A network of strong-motion accelerograph was installed at the Lawrence Livermore National Laboratory (LLNL) as part of site seismic safety program. The network has two objectives: to provide quantitative information on the severity of ground shaking for the assessment of structural effects at LLNL following an earthquake, and to provide data for analyses of the free-field ground motion and the causative earthquake. The network includes digital multichannel central-recording systems in Building 111 (9-channel) and in Building 332 (18-channel). Independent analog accelerographs are included to provide redundancy. A multichannel system was also installed on the spaceframe at the Laser facility. In addition to the structural instrumentation, six free-field stations are located at and near the Laboratory. The strong-motion network will provide rapid indication of peak ground-motion values as well as data for detailed post-earthquake studies of ground motion and structural response.

Shakal, A. F.; Murray, R. C.

1981-10-01

57

CONTROLLING FACTORS OF STRONG GROUND MOTION PREDICTION FOR SCENARIO EARTHQUAKES  

Microsoft Academic Search

SUMMARY High probability of future earthquake occurrence on active faults in the western Biwa lake area in Kansai region, Japan, are presented by the nation-level committee on the long-term evaluation. Seismic hazard assessment based on the proper prediction of strong ground motion is the central issue to disaster mitigation for urban area. We simulate ground motions from Mw6.5 class scenario

Hiroe MIYAKE; Tomotaka IWATA; Kojiro IRIKURA

58

Phase derivatives and simulation of strong ground motions  

USGS Publications Warehouse

Phase derivatives can be used to compute instantaneous frequency and envelope delay (also known as group delay). Envelope delay, in the guise of phase differences, has been used by engineers in the simulation of strong ground motion, particularly as a way of controlling the duration of motion. Simulations using the stochastic method, in which duration is a simple function of source duration and a path-dependent duration, possess envelope delay properties similar to those from simulations based on phase differences. Envelope delay provides a way of extending the standard stochastic method to produce nonstationary frequency content, as produced by ground motions containing surface waves.

Boore, D. M.

2003-01-01

59

Blind Prediction of Near-Fault Strong Ground Motions  

NASA Astrophysics Data System (ADS)

The Mw 7.9 Alaska earthquake provides an unprecedented opportunity to analyze strong ground motion recordings obtained very close to a large magnitude crustal earthquake. Several strong motion sites are located along the route of the Alaska Pipeline which crosses roughly perpendicular to the fault rupture about 85 km east of the epicenter. The closest site is located about 3 km from the fault. Prior to the release of these data, we conducted a blind prediction experiment to estimate the ground motion waveforms at this closest recording site. Ground motions are computed using the both one realization of the stochastic composite source simulation methodology of Zeng (1994) and the deterministic simulation of Somerville et al. (1994). Both techniques utilize full waveform Greens functions calculated for plane layered velocity structures. Due to uncertainty in the distribution of slip during the event, the deterministic simulation used both uniform and heterogeneous models of the slip distribution. Predictions were made without accurate knowledge of site conditions or fault-station geometry. In all cases, the simulated motions are characterized by pulse-like motions that exhibit strong rupture directivity effects. Peak fault-normal ground velocities and displacements are about twice as large as corresponding peak fault-parallel motions. For the heterogeneous slip models, peak velocities for the two simulation methodologies are 50-95 cm/s, and peak dynamic displacements are 60-150 cm. In addition, these simulations predict static horizontal offsets of 50-170 cm, depending on the component. Plots of the simulated motions and more detailed descriptions of the parameterizations can be found at http://www.seismo.unr.edu/blind.

Anderson, J.; Graves, R.; Zeng, Y.; Somerville, P.

2002-12-01

60

A simple model for strong ground motions and response spectra  

USGS Publications Warehouse

A simple model for the description of strong ground motions is introduced. The model shows that response spectra can be estimated by using only four parameters of the ground motion, the RMS acceleration, effective duration and two corner frequencies that characterize the effective frequency band of the motion. The model is windowed band-limited white noise, and is developed by studying the properties of two functions, cumulative squared acceleration in the time domain, and cumulative squared amplitude spectrum in the frequency domain. Applying the methods of random vibration theory, the model leads to a simple analytical expression for the response spectra. The accuracy of the model is checked by using the ground motion recordings from the aftershock sequences of two different earthquakes and simulated accelerograms. The results show that the model gives a satisfactory estimate of the response spectra.

Safak, Erdal; Mueller, Charles; Boatwright, John

1988-01-01

61

Predicting Strong Ground Motion from Weak Ground Motion (Beno Gutenberg Medal Lecture)  

NASA Astrophysics Data System (ADS)

Predicting strong ground motion from future earthquakes is among the most important research topics in seismology. Typically, seismologists do this through ground motion prediction equations that express relationships between earthquake characteristics and ground motion intensity. In some locations (e.g., Cascadia) there is relatively little data to constrain these relationships. For all areas there is the problem that there are few records of ground motion available close to large earthquakes. As a result, seismologists are increasingly turning to simulations to compensate for this lack of data, but validating the accuracy of these simulations is critically important. In this talk I present two new approaches for strong ground motion prediction. Both methods rely on data that is approximately one million times weaker in amplitude than the strong ground motion of interest. The first method uses the recently discovered phenomenon of tectonic tremor to constrain the amplitude decay with distance of seismic waves in subduction zones. The abundant data represented by tremor should allow us to explore the variability of ground motion with distance both regionally, and between different subduction zones. The second method uses the ambient seismic field to construct virtual earthquakes that predict spatial variations in long period strong ground motion for scenario earthquakes.

Beroza, Gregory

2014-05-01

62

Catalog of strong motion stations in Eastern North America  

NASA Astrophysics Data System (ADS)

The catalog contains information on all strong motion stations operating in Eastern North America known to the National Center for Earthquake Engineering Research (NCEER). The location, coordinates, installation dates, type of instrument, operator, structure type and size, and site geology are listed for each station. The format of the catalog is patterned after the United States Geological Survey (USGS) Open-File Report 81-664, 'Western Hemisphere Strong-Motion Accelerograph Station List-1980' but the entries have been updated as of January 1990. There are 237 stations listed in the catalog which include 414 recording instruments. One third of these stations are intended to record free-field ground motion while the rest are associated with large engineered structures. The relationship of station location to seismicity is shown in a series of figures and a method is described to predict peak acceleration levels from an earthquake where the magnitude and distance to station are known.

Busby, R. W.

1990-04-01

63

Strong Motion Observations In India-synthesis of Results  

Microsoft Academic Search

During the last two decades strong motion arrays have been installed in the various parts of Himalaya including N-E India through the Department of Science &Technology. Several moderate earthquakes have been recorded by these networks, which have brought out interesting results about the pattern of attenuation of ground acceleration in these regions. The networks are being strengthened further covering the

B. K. Bansal; G. D. Gupta; H. N. Srivastava

2002-01-01

64

Catalog of strong motion stations in Eastern North America  

Microsoft Academic Search

The catalog contains information on all strong motion stations operating in Eastern North America known to the National Center for Earthquake Engineering Research (NCEER). The location, coordinates, installation dates, type of instrument, operator, structure type and size, and site geology are listed for each station. The format of the catalog is patterned after the United States Geological Survey (USGS) Open-File

R. W. Busby

1990-01-01

65

STRONG MOTION RECORD THAN JANUARY TO JUNE 2007  

Microsoft Academic Search

Iran Strong Motion Network started its activities in 1973 and running by Building and Housing Research Center since 1981. At the date of this study ISMN consisted of more than 1103 digital (SSA-2) and 15 analog (SMA-1) accelerographs. The accelerograms of different earthquake, are downloaded, controlled, processed, and then added to the comprehensive data bank, which is very useful for

H. Mirzaei Alavijeh; E. Farzanegan

66

ANALYSIS OF ERRORS IN DIGITIZED STRONG-MOTION ACCELEROGRAMS  

Microsoft Academic Search

To devise the optimum procedures for the processing of digitized strong- motion accelerograms, detailed error analysis is required. This paper summarizes some aspects of previous error analyses (Trifunac, 1970; Trifunac et al., 1971) and adds the results of several recent investigations. The error analysis described here is divided into two main parts. The first part deals with particular sources of

M. D. TRIFUNAC; F. E. UDWADIA; A. G. BRADY

1973-01-01

67

EMPIRICAL STRONG GROUND MOTION ATTENUATION RELATIONS FOR NORTHWESTERN TURKEY  

Microsoft Academic Search

Using a random effects model that takes into consideration the correlation of data recorded by a single event, we employ a database consisting of 195 recordings from recent seismic events to develop empirical attenuation relationships for the geometric mean of horizontal peak ground acceleration (pga) and 5-percent damped spectral acceleration (Sa). The recordings employed were obtained from strong motion stations

Cem ÖZBEY; Ali SARI; Lance MANUEL; Mustafa ERDIK; Yasin FAHJAN

2003-01-01

68

Probabilistic Motion Planning of Balloons in Strong, Uncertain Wind Fields  

E-print Network

Probabilistic Motion Planning of Balloons in Strong, Uncertain Wind Fields Michael T. Wolf, Lars for Montgolfier´e balloons in the atmosphere of Titan. The goal of the algorithm is to determine what altitude´e (hot air) balloons using wind models for time-efficient paths. The method was developed for studying

Williams, Brian C.

69

Strong motion observations and recordings from the great Wenchuan Earthquake  

USGS Publications Warehouse

The National Strong Motion Observation Network System (NSMONS) of China is briefly introduced in this paper. The NSMONS consists of permanent free-field stations, special observation arrays, mobile observatories and a network management system. During the Wenchuan Earthquake, over 1,400 components of acceleration records were obtained from 460 permanent free-field stations and three arrays for topographical effect and structural response observation in the network system from the main shock, and over 20,000 components of acceleration records from strong aftershocks occurred before August 1, 2008 were also obtained by permanent free-field stations of the NSMONS and 59 mobile instruments quickly deployed after the main shock. The strong motion recordings from the main shock and strong aftershocks are summarized in this paper. In the ground motion recordings, there are over 560 components with peak ground acceleration (PGA) over 10 Gal, the largest being 957.7 Gal. The largest PGA recorded during the aftershock exceeds 300 Gal. ?? 2008 Institute of Engineering Mechanics, China Earthquake Administration and Springer-Verlag GmbH.

Li, X.; Zhou, Z.; Yu, H.; Wen, R.; Lu, D.; Huang, M.; Zhou, Y.; Cu, J.

2008-01-01

70

Turkish strong ground motion data acquisition and analysis  

NASA Astrophysics Data System (ADS)

The installation of a strong-motion network in Turkey was initiated in 1973 under the sponsorship of the Earthquake Research Institute. Today, 61 accelerographs and 40 seismoscope stations have been installed along the most active seismic zones, namely the North Anatolian zone and in the graben systems of western Anatolia. All the strong ground motion records, which were obtained during the period 1973-1983, are listed in the tables. The date, origin time and body-wave magnitude of the events are given together with the local intensity, focal distance of the recording station and maximum acceleration registered by the instrument. Information about the significant earthquakes, which were recorded by SMA-1 Kinemetrics type accelerographs, are also given in the following. August 19, 1976 Denizli earthquake in western Anatolia with a magnitude 4.7, caused considerable damage in the city. It is interesting to note that this was the first earthquake whose strong motion was recorded by an accelerograph located within the epicentral area. The baseline corrected acceleration and velocity values for the N-S component is calculated to be 34.21% g and 21.35 cm s -1. November 24, 1976 Çaldiran earthquake in eastern Anatolia showed the spectral acceleration of 11.2% g for a natural period of 0.73 s. December 9 and 16, 1977 ?zmir earthquakes with magnitudes 4.8 and 5.3 caused damage at various locations in ?zmir. The two earthquakes were recorded by a SMA-1 and by two seismoscopes, and showed the acceleration values reaching 21% g in the E-W component. The strong-motion accelerographs of the other earthquakes that occurred in the 1973-1982 period were also processed and preliminary evaluation of the data was studied taking the damage distribution and the site conditions into consideration.

Ates, Ref'an

1985-04-01

71

New Downhole Strong-Motion Data Recorded at Tarzana Array  

Microsoft Academic Search

Significantly amplified ground accelerations at the Tarzana station were recorded during many, but not all, earthquakes (e.g., Shakal et al., 1988). Peak horizontal ground acceleration at the Tarzana station during the M7.1 Hector Mine earthquake was almost twice as large as the accelerations recorded at nearby stations. After the Northridge earthquake the California Strong Motion Instrumentation Program (CSMIP) significantly increased

V. Graizer; A. Shakal; H. Haddadi

2001-01-01

72

Advanced sensitivity calibration of the Los Angeles strong motion array  

Microsoft Academic Search

SUMMARY Results are presented of recent sensitivity calibration of 76 accelerographs (SMA-1) of the Los Angeles Strong Motion Array. These have pendulum-like transducers and optical recording system. One characteristic of their design is o?-axis sensitivity, which is magnified by transducer misalignment. A new calibration procedure was applied, which considers o?-axis sensitivity and measures the angles of misalignment (u and t),

Maria I. Todorovska; Elena I. Novikova; Mihailo D. Trifunac; SANJA S. IVANOVIC

1998-01-01

73

Can mobile phones used in strong motion seismology?  

NASA Astrophysics Data System (ADS)

Micro Electro-Mechanical Systems (MEMS) accelerometers are electromechanical devices able to measure static or dynamic accelerations. In the 1990s MEMS accelerometers revolutionized the automotive-airbag system industry and are currently widely used in laptops, game controllers and mobile phones. Nowadays MEMS accelerometers seems provide adequate sensitivity, noise level and dynamic range to be applicable to earthquake strong motion acquisition. The current use of 3 axes MEMS accelerometers in mobile phone maybe provide a new means to easy increase the number of observations when a strong earthquake occurs. However, before utilize the signals recorded by a mobile phone equipped with a 3 axes MEMS accelerometer for any scientific porpoise, it is fundamental to verify that the signal collected provide reliable records of ground motion. For this reason we have investigated the suitability of the iPhone 5 mobile phone (one of the most popular mobile phone in the world) for strong motion acquisition. It is provided by several MEMS devise like a three-axis gyroscope, a three-axis electronic compass and a the LIS331DLH three-axis accelerometer. The LIS331DLH sensor is a low-cost high performance three axes linear accelerometer, with 16 bit digital output, produced by STMicroelectronics Inc. We have tested the LIS331DLH MEMS accelerometer using a vibrating table and the EpiSensor FBA ES-T as reference sensor. In our experiments the reference sensor was rigidly co-mounted with the LIS331DHL MEMS sensor on the vibrating table. We assessment the MEMS accelerometer in the frequency range 0.2-20 Hz, typical range of interesting in strong motion seismology and earthquake engineering. We generate both constant and damped sine waves with central frequency starting from 0.2 Hz until 20 Hz with step of 0.2 Hz. For each frequency analyzed we generate sine waves with mean amplitude 50, 100, 200, 400, 800 and 1600 mg0. For damped sine waves we generate waveforms with initial amplitude of 2 g0. Our tests show as, in the frequency and amplitude range analyzed (0.2-20 Hz, 10-2000 mg0), the LIS331DLH MEMS accelerometer have excellent frequency and phase response, comparable with that of some standard FBA accelerometer used in strong motion seismology. However, we found that the signal recorded by the LIS331DLH MEMS accelerometer slightly underestimates the real acceleration (of about 2.5%). This suggests that may be important to calibrate a MEMS sensor before using it in scientific applications. A drawback of the LIS331DLH MEMS accelerometer is its low sensitivity. This is an important limitation of all the low cost MEMS accelerometers; therefore nowadays they are desirable to use only in strong motion seismology. However, the rapid development of this technology will lead in the coming years to the development of high sensitivity and low noise digital MEMS sensors that may be replace the current seismic accelerometer used in seismology. Actually, the real main advantage of these sensors is their common use in the mobile phones.

D'Alessandro, Antonino; D'Anna, Giuseppe

2013-04-01

74

Seismographic Systems It is common to separate seismographic systems into "seismographs" and "strong-motion  

E-print Network

" and "strong-motion accelerographs." Seismographs have generally been developed by geophysicists and seismographs are typically designed to record ground motions that are far too small to be felt. Strong-motion of these two systems. Seismographs (including strong-motion accelerometers) consist of (at least) a sensing

Heaton, Thomas H.

75

THE HYBRID EMPIRICAL METHOD AND ITS USE IN PREDICTIONG STRONG GROUND MOTION IN EUROPE  

Microsoft Academic Search

SUMMARY Ground motion models (attenuation relationships) are used to estimate strong ground motion for many engineering and seismological applications. Where strong-motion recordings are abundant, these models are developed empirically from these recordings. Where strong-motion recordings are sparse, they are often developed from seismological models using the Stochastic or Theoretical Methods. Although use of these latter methods has become common place,

Kenneth W. CAMPBELL

2006-01-01

76

Strong motions in Alaska-type subduction zone environments  

SciTech Connect

Peak accelerations of Alaska-Aleutian strong motion records are compared with those collected mostly in the western US. The most prominent difference is the larger scatter of Alaskan peak accelerations. The high scatter is attributed primarily to high variability of stress drops typical for some subduction zones. For critical engineering projects that must satisfy high probabilities of non-exceedence it implies that in Alaskan-type environments higher design peak accelerations may have to be adopted than under comparable cricumstances in the western US.

Jacob, K.H.; Mori, J.

1984-01-01

77

Database for earthquake strong motion studies in Italy  

USGS Publications Warehouse

We describe an Italian database of strong ground motion recordings and databanks delineating conditions at the instrument sites and characteristics of the seismic sources. The strong motion database consists of 247 corrected recordings from 89 earthquakes and 101 recording stations. Uncorrected recordings were drawn from public web sites and processed on a record-by-record basis using a procedure utilized in the Next-Generation Attenuation (NGA) project to remove instrument resonances, minimize noise effects through low- and high-pass filtering, and baseline correction. The number of available uncorrected recordings was reduced by 52% (mostly because of s-triggers) to arrive at the 247 recordings in the database. The site databank includes for every recording site the surface geology, a measurement or estimate of average shear wave velocity in the upper 30 m (Vs30), and information on instrument housing. Of the 89 sites, 39 have on-site velocity measurements (17 of which were performed as part of this study using SASW techniques). For remaining sites, we estimate Vs30 based on measurements on similar geologic conditions where available. Where no local velocity measurements are available, correlations with surface geology are used. Source parameters are drawn from databanks maintained (and recently updated) by Istituto Nazionale di Geofisica e Vulcanologia and include hypocenter location and magnitude for small events (M< ??? 5.5) and finite source parameters for larger events. ?? 2009 A.S. Elnashai & N.N. Ambraseys.

Scasserra, G.; Stewart, J.P.; Kayen, R.E.; Lanzo, G.

2009-01-01

78

Future of the US National Strong-Motion Program  

USGS Publications Warehouse

These reports are presented in response to a charge of the Earthquake Hazards Reduction Program (EHRP) Program Council of the U.S. Geological Survey to 'define the future of the USGS National Strong-Motion Program (NSMP)' (Appendix A). The council requested that a 'Vision Paper' and an 'Options Document' be prepared. Each of these reports is a separate document. The 'Executive Summary' of both reports is presented here under separate cover. The content of the reports and the executive summary is organized to the extent possible according to the main charges of the EHRP Program Council. Detailed evaluation of charges and questions posed by the Council with the benefit of modern GIS tools and the recent deliberations of three national workshops have yielded substantial new insight regarding the status of strong-motion measurement in the US. These reports are intended as an objective evaluation of the nation's need and capability to record the next major earthquake at locations of most significance for public safety.

1997-01-01

79

Coherence, Strain, and Phase Velocity of Strong Ground Motions in the Mississippi Charles A. Langston  

E-print Network

wave field can only be determined using dense arrays of strong motion accelerographs to record strong1 Coherence, Strain, and Phase Velocity of Strong Ground Motions in the Mississippi Embayment.0 March 13, 2005 #12;2 Abstract Two strong motion arrays were deployed for the October 2002 Embayment

Langston, Charles A.

80

Temporal and spatial variation of stress field in Taiwan from 1991 to 2007: Insights from comprehensive first motion focal mechanism catalog  

NASA Astrophysics Data System (ADS)

The total amount of 4,761 focal mechanisms was determined based on P-wave first motion polarities from 1991 to 2007 in Taiwan region. This dataset offers us a good opportunity to examine temporal and spatial variability of the stress field. We find that the spatial variations of stress axes are mainly controlled by tectonic structures while the temporal changes are greatly influenced by the Chi-Chi earthquake. The orientation of the maximum horizontal compressive stress axes (S H) shows a general agreement with the direction of plate motion between a depth range of 0-30 km. The 20° anticlockwise rotation of S H from the Longitudinal Valley (LV) to western Taiwan is probably caused by the left-lateral motion on the Longitudinal Valley Fault (LVF) that has consumed part of the oblique motion of plate convergence. On the other hand, part of the oblique convergence is transferred into the Central Range and the Hsuehshan Range judging from counterclockwise rotation of S H from east to west and strike-slip faulting in the Hsuehshan Range. Most events with a depth greater than 30 km occur offshore eastern Taiwan and the azimuth of S H is close to E-W directed, different from NW-SE directed at shallow depths. This may infer the existence of the transition of lithosphere rheology in offshore eastern Taiwan. The trends of S H in the depth of 0-10 km are strongly affected by the coseismic stress change of the Chi-Chi earthquake. In the northern half of the Chi-Chi rupture area, the trends of S H rotate 30° clockwise and the stress ratio increased by a factor of six after the mainshock. The orientations of S H still differ by 30° in 2007 comparing to that in the period before the Chi-Chi earthquake. The variation of S H trend is more diverse in the southern half of the rupture area, showing 20° counterclockwise rotation immediately after the 1999 mainshock followed by a clockwise rotation. The trend of S H returns to the pre-seismic direction of 110° in 2001. These notable changes of S H before and after the Chi-Chi mainshock suggests that the magnitude of background stress in the rupture area is close to the coseismic stress drop. We also recognize a significant 10° counterclockwise rotation of S H in the entire Chi-Chi rupture area between 1991 and 1999 before the earthquake took place. However, to the south of the Chi-Chi rupture, the trends of S H remain little changed before and after the Chi-Chi earthquake.

Wu, Yih-Min; Hsu, Ya-Ju; Chang, Chien-Hsin; Teng, Louis Suh-yui; Nakamura, Mamoru

2010-10-01

81

A Quantitative Approach for Estimating Coseismic Displacements in the Near Field from Strong-Motion Accelerographs  

E-print Network

records. Introduction The determination of coseismic displacements from strong-motion accelerographs A Quantitative Approach for Estimating Coseismic Displacements in the Near Field from Strong-Motion accelerations recorded by strong-motion seismometers are often contaminated by baseline offsets that prevent

Cerveny, Vlastislav

82

Ground rotational motions of the 1999 Chi-Chi, Taiwan earthquake as inferred from dense array observations  

Microsoft Academic Search

Large rotational motions excited by the 1999 Chi-Chi, Taiwan earthquake are inferred from a dense acceleration array near the northern end of the rupture fault where large surface slips along the fault are observed. The estimated major frequency content is from 0.1 to 1.0 Hz with a peak near 0.2 Hz. It is found that in the footwall region the

Bor-Shouh Huang

2003-01-01

83

Another Look at Strong Ground Motion Accelerations and Stress Drop  

NASA Astrophysics Data System (ADS)

The relationship between earthquake stress drop and ground motion acceleration is central to seismic hazard analysis. We revisit measurements of root-mean-square (RMS) acceleration, arms, using KikNet accelerometer data from Japan. We directly measure RMS and peak acceleration, and estimate both apparent stress and corner frequencies using the empirical Green’s function (eGf) coda method of Baltay et al. [2010]. We predict armsfrom corner frequency and stress drop following McGuire and Hanks [1980] to compare with measurements. The theoretical relationship does a good job of predicting observed arms. We use four earthquake sequences in Japan to investigate the source parameters and accelerations: the 2008 Iwate-Miyagi earthquake; the off-Kamaishi repeating sequence; and the 2004 and 2007 Niigata events. In each data set, we choose events that are nearly co-located so that the path term to any station is constant. Small events are used as empirical Green’s functions to correct for propagation effects. For all sequences, we find that the apparent stress averages ~1 MPa for most events. Corner frequencies are consistent with Mo-1/3 scaling. We find the ratio of stress drop and apparent stress to be 5, consistent with the theoretical derivation of Singh and Ordaz [1994], using a Brune [1970] spectra. armsis theoretically proportional to stress drop and the inverse square root of the corner frequency. We show that this calculation can be used as a proxy for armsobservations from strong motion records, using recent data from the four earthquake sequences mentioned above. Even for the Iwate-Miyagi mainshock, which experienced over 4 g’s of acceleration, we find that apparent stress, stress drop and corner frequency follow expected scaling laws and support self-similarity.

Baltay, A.; Prieto, G.; Ide, S.; Hanks, T. C.; Beroza, G. C.

2010-12-01

84

New Downhole Strong-Motion Data Recorded at Tarzana Array  

NASA Astrophysics Data System (ADS)

Significantly amplified ground accelerations at the Tarzana station were recorded during many, but not all, earthquakes (e.g., Shakal et al., 1988). Peak horizontal ground acceleration at the Tarzana station during the M7.1 Hector Mine earthquake was almost twice as large as the accelerations recorded at nearby stations. After the Northridge earthquake the California Strong Motion Instrumentation Program (CSMIP) significantly increased instrumentation at Tarzana to study the unusual site amplification effect. Current instrumentation at Tarzana consists of an accelerograph at the top of Tarzana hill (Tarzana - Cedar Hill B), a downhole instrument at 60 m depth, and an accelerograph at the foot of the hill (Tarzana - Clubhouse), 180 m from the Cedar Hill B station. The original station, Tarzana - Cedar Hill Nursery A, was lost in 1999 due to construction. Thirteen events, including the Hector Mine earthquake, were simultaneously recorded by these instruments at Tarzana. The downhole instrument (A) was used as a reference site to compare the amplification effects at the top of Tarzana hill (B) and at the foot of the hill (C). Spectral amplification from the bottom of the hole to the top of the hill (B/A) and to the foot of the hill (C/A) is similar along the component parallel to the strike of Tarzana hill. But B/A is almost double C/A along the component transverse to the strike of the hill in period range from 0.04 to 0.8 sec (1.2 to 25 Hz). Comparison of the response spectra demonstrates clear directional site response resonance (perpendicular to the strike of the hill) at Tarzana. In contrast to accelerations recorded during the Mw 7.1 Hector Mine earthquake (high frequency part of seismic signal), displacements (relatively low frequency part of seismic signal) demonstrate almost no site amplification from the bottom of the hole to the surface (B/A) at periods greater than 1.5 sec, in either direction. Ground displacements at other CSMIP downhole arrays which recorded the Hector Mine earthquake also demonstrate almost no near-surface site amplification at long periods. Comparison of empirical and theoretical site amplification effects at Tarzana was performed using SHAKE91 modeling motion separately in the longitudinal and transverse directions. The source of the site amplification that produces large motions at Tarzana is still under investigation. The topography, shear-wave velocity profile and three-dimensional structure of the site apparently all contribute to the higher amplification of ground motion at the Tarzana site. The studies of Tarzana were co-funded by CSMIP and by the National Science Foundation (NSF) through the Resolution of Site Response Issues from the Northridge Earthquake Project (ROSRINE).

Graizer, V.; Shakal, A.; Haddadi, H.

2001-12-01

85

An Automatic System for Real-Time Determination of Earthquake Focal Mechanism and Ground Motion in Taiwan  

NASA Astrophysics Data System (ADS)

We have developed a computational platform for automatic and real-time determination of focal mechanisms and ground motion distributions from earthquakes in the Taiwan region. This automatic system is composed of two parts: (1) determination of earthquake focal mechanisms by waveform inversion based on 1D structural model, and (2) calculation of ground motion distributions using Green tensors in a realistic 3D structural model. For focal mechanism solutions, we use the cut-and-paste (CAP) method of Zhu and Helmberger [1] which offers an efficient means of obtaining reliable estimations of earthquake source properties including fault-plane solutions, focal depths and moment magnitudes by fitting broadband waveforms of P, S and surface waves. For real-time calculation of ground motions, we adopt the strain Green tensor (SGT) database approach of Zhao et al. [2]. The SGT database is established for a realistic regional 3D model by finite-difference simulations, and therefore real-time calculation of ground motion is replaced by simple extractions of appropriate Green's functions from the database and multiplication with the moment tensor. In our current implementation, we use waveform records at stations from the Broadband Array in Taiwan for Seismology (BATS) and earthquake epicenters (latitudes and longitudes) from alerts issued by the early warning system at the Central Weather Bureau of Taiwan. We also take the effects of surface topography and site amplification into account to further improve the reality and accuracy of the ground motion estimations. Shake movies and shake maps can also be generated automatically for quick assessment of earthquake intensity and damage distribution, disaster relief operation, and public information dissemination.

Zhao, L.; Hsieh, M.; Liang, W.; Tsai, C.

2011-12-01

86

Influence of Uncertain Source Parameters on Strong Ground Motion Simulation with the Empirical Green's Function Method  

Microsoft Academic Search

A combined stochastic and Green's function approach was developed to simulate strong ground motions in Southwest Western Australia (SWWA) in a previous study. Although it was demonstrated that adopting the source parameters derived from other regions yielded reasonable simulation of ground motions in SWWA as compared with a few available strong motion records, the effect of source parameter variations on

Jonathan Z. Liang; Hong Hao

2009-01-01

87

Perceptual Training Strongly Improves Visual Motion Perception in Schizophrenia  

ERIC Educational Resources Information Center

Schizophrenia patients exhibit perceptual and cognitive deficits, including in visual motion processing. Given that cognitive systems depend upon perceptual inputs, improving patients' perceptual abilities may be an effective means of cognitive intervention. In healthy people, motion perception can be enhanced through perceptual learning, but it…

Norton, Daniel J.; McBain, Ryan K.; Ongur, Dost; Chen, Yue

2011-01-01

88

Recovery of Near-Fault Ground Motions From the Strong-Motion Records of the 2008 Wenchuan, China Earthquake  

Microsoft Academic Search

Near-fault ground motions are important data to both the seismological and engineering studies and recovery them from the strong-motion records is an essential step to keep data to be properly used. Since the Near-fault ground motion is rich in source information and less effect from the complex wave propagation path, it could be useful information for improving our understating of

H. Chiu

2009-01-01

89

Strong ground motions generated by earthquakes on creeping faults  

NASA Astrophysics Data System (ADS)

tenet of earthquake science is that faults are locked in position until they abruptly slip during the sudden strain-relieving events that are earthquakes. Whereas it is expected that locked faults when they finally do slip will produce noticeable ground shaking, what is uncertain is how the ground shakes during earthquakes on creeping faults. Creeping faults are rare throughout much of the Earth's continental crust, but there is a group of them in the San Andreas fault system. Here we evaluate the strongest ground motions from the largest well-recorded earthquakes on creeping faults. We find that the peak ground motions generated by the creeping fault earthquakes are similar to the peak ground motions generated by earthquakes on locked faults. Our findings imply that buildings near creeping faults need to be designed to withstand the same level of shaking as those constructed near locked faults.

Harris, Ruth A.; Abrahamson, Norman A.

2014-06-01

90

Deployment of strong-motion instrumentation at Lawrence Livermore National Laboratory  

Microsoft Academic Search

A network of strong-motion accelerographs has been deployed at the Lawrence Livermore National Laboratory (LLNL) as part of the Site Seismic Safety Program. The network has three objectives: (1) the measurement of free-field ground motion for analyses of the ground shaking and its variation at the site, (2) measurement of the motion in certain buildings for detailed analyses of structural

A. F. Shakal; R. C. Murray

1982-01-01

91

Strong Motion Networks - Rapid Response and Early Warning Applications in Istanbul  

Microsoft Academic Search

In recent years several strong motion networks have been established in Istanbul with a preparation purpose for future probable earthquake. This study addresses the introduction of current seismic networks and presentation of some recent results recorded in these networks. Istanbul Earthquake Early Warning System Istanbul Earthquake Early Warning System has ten strong motion stations which were installed as close as

C. Zulfikar; H. Alcik; O. Ozel; M. Erdik

2009-01-01

92

RECENT ADVANCES IN GREECE ON STRONG-MOTION NETWORKING AND DATA PROCESSING  

Microsoft Academic Search

Significant progress has been achieved in Greece during the last two decades concerning the development and maintenance of the accelerographic networks, as well as in the acquisition and processing of the strong-motion data. Several new aspects for the design and deployment of the Greek strong-motion network have been recently adopted. A significant number of accelerographic arrays have been deployed covering

A. Skarlatoudis; B. Margaris; C. Papazachos

93

THE NEW STRONG MOTION SEISMIC NETWORK IN SOUTHWEST BRITISH COLUMBIA, CANADA  

Microsoft Academic Search

SUMMARY The Geological Survey of Canada has designed a new type of low-cost strong motion seismometer and is currently updating its strong motion seismic network with the new instruments. As of January 2004 about fifty instruments are in operation in Southwestern British Columbia and in a dense urban demonstration network in the cities of Vancouver and Richmond. With a noise

Andreas ROSENBERGER; Ken BEVERLEY; Garry ROGERS

2004-01-01

94

Spanish national strong motion network. Recording of the Huelva earthquake of 20 December, 1989  

Microsoft Academic Search

In recent years a network of 30 accelerographs has been installed through the zones of highest seismic activity of Spain. For the first time, digital strong motion records have been obtained in Spain, with a maximum horizontal acceleration value of 0.06 g. A comprehensive study is made of the strong motion recordings of an earthquake which occurred in southwest Spain,

E. Carreño; J. Rueda; C. López Casado; J. Galán; J. A. Peláez

1991-01-01

95

Analysis of strong motion data from the New Madrid seismic zone 1975 - 1976  

Microsoft Academic Search

Strong motion data from three earthquakes is presented. One accelerograph was triggered by the mb = 4.2 June 13, 1975 event, seven were triggered by an mb = 5.0 event on March 25, 1976, and one was triggered by an mb = 4.5 aftershock on March 25, 1976. The strong motion data were processed using the computer programs developed at

R. B. Herrmann

1977-01-01

96

Strong Ground Motion from the Urakawa Earthquake of Jan. 25, 1989  

Microsoft Academic Search

A moderate size earthquake (M = 5.8, H = 49 km) occurred on Jan. 25, 1989 beneath Urakawa, southern part of Hokkaido. Strong ground motions during this earthquake were well recorded by 10 accelerographs and 2 velocity-type strong motion seismographs. The recorded peak accelerations range from 320 down to 1 cm\\/sec 2 , depending on epicentral distances from 4 to

Abbas Mahdavian; Tsutomu Sasatani

97

Seismographic Systems 4/14/2014 It is common to separate seismographic systems into "seismographs" and "strong-motion  

E-print Network

into "seismographs" and "strong-motion accelerographs." Seismographs have generally been developed by geophysicists and seismographs are typically designed to record ground motions that are far too small to be felt. Strong-motion of these two systems. Seismographs (including strong-motion accelerometers) consist of (at least) a sensing

Heaton, Thomas H.

98

Holographic Brownian motion and time scales in strongly coupled plasmas  

NASA Astrophysics Data System (ADS)

We study Brownian motion of a heavy quark in field theory plasma in the AdS/CFT setup and discuss the time scales characterizing the interaction between the Brownian particle and plasma constituents. Based on a simple kinetic theory, we first argue that the mean-free-path time is related to the connected 4-point function of the random force felt by the Brownian particle. Then, by holographically computing the 4-point function and regularizing the IR divergence appearing in the computation, we write down a general formula for the mean-free-path time, and apply it to the STU black hole which corresponds to plasma charged under three U(1)R-charges. The result indicates that the Brownian particle collides with many plasma constituents simultaneously.

Atmaja, Ardian Nata; de Boer, Jan; Shigemori, Masaki

2014-03-01

99

SISMA (Site of Italian Strong Motion Accelerograms): a Web-Database of Ground Motion Recordings for Engineering Applications  

NASA Astrophysics Data System (ADS)

The paper describes a new website called SISMA, i.e. Site of Italian Strong Motion Accelerograms, which is an Internet portal intended to provide natural records for use in engineering applications for dynamic analyses of structural and geotechnical systems. SISMA contains 247 three-component corrected motions recorded at 101 stations from 89 earthquakes that occurred in Italy in the period 1972-2002. The database of strong motion accelerograms was developed in the framework of a joint project between Sapienza University of Rome and University of California at Los Angeles (USA) and is described elsewhere. Acceleration histories and pseudo-acceleration response spectra (5% damping) are available for download from the website. Recordings can be located using simple search parameters related to seismic source and the recording station (e.g., magnitude, Vs30, etc) as well as ground motion characteristics (e.g. peak ground acceleration, peak ground velocity, peak ground displacement, Arias intensity, etc.).

Scasserra, Giuseppe; Lanzo, Giuseppe; Stewart, Jonathan P.; D'Elia, Beniamino

2008-07-01

100

The importance of strong motion seismology in India  

Microsoft Academic Search

The high seismicity of portions of the Indian peninsula, together with the high density of population and industrial growth,\\u000a results in a significant seismic risk in many parts of the subcontinent. Large construction projects throughout the peninsula\\u000a require an adequate basis for earthquake-resistant design. Thus, as well as strong scientific arguments, there are major practical\\u000a reasons why a substantial programme

Bruce A Bolt; James N Brune

1989-01-01

101

Strong ground motion simulation of the 2003 Bam, Iran, earthquake using the empirical Green's function method  

NASA Astrophysics Data System (ADS)

The 2003 Bam, Iran, earthquake caused catastrophic damage to the city of Bam and neighboring villages. Given its magnitude ( M w ) of 6.5, the damage was remarkably large. Large-amplitude ground motions were recorded at the Bam accelerograph station in the center of Bam city by the Building and Housing Research Center (BHRC) of Iran. We simulated the Bam earthquake acceleration records at three BHRC strong-motion stations—Bam, Abaraq, and Mohammad-Abad—by the empirical Green's function method. Three aftershocks were used as empirical Green's functions. The frequency range of the empirical Green's function simulations was 0.5-10 Hz. The size of the strong motion generation area of the mainshock was estimated to be 11 km in length by 7 km in width. To estimate the parameters of the strong motion generation area, we used 1D and 2D velocity structures across the fault and a combined source model. The empirical Green's function method using a combination of aftershocks produced a source model that reproduced ground motions with the best fit to the observed waveforms. This may be attributed to the existence of two distinct rupture mechanisms in the strong motion generation area. We found that the rupture starting point for which the simulated waveforms best fit the observed ones was near the center of the strong motion generation area, which reproduced near-source ground motions in a broadband frequency range. The estimated strong motion generation area could explain the observed damaging ground motion at the Bam station. This suggests that estimating the source characteristics of the Bam earthquake is very important in understanding the causes of the earthquake damage.

Sadeghi, Hossein; Miyake, Hiroe; Riahi, Ali

2013-04-01

102

The role of strong motion rotations in the response of structures near earthquake faults  

Microsoft Academic Search

Early studies of earthquake strong motion assumed linear materials and small deformations. It was observed that under favorable conditions (long waves), the accompanying rotational motions are usually small, and so their effects could be neglected. In 1932, when Biot opted for the vibrational method of solution of the dynamic response problems [Trifunac MD. 75th anniversary of the response spectrum method—a

Mihailo D. Trifunac

2009-01-01

103

75th anniversary of strong motion observation—A historical review  

Microsoft Academic Search

This review describes the experience accumulated in the field of recording earthquake motions up to the early 1900s, and then it discusses the key players who contributed to the first successful strong motion observation program in earthquake engineering in the 1930s. It begins by summarizing the accomplishments of the preceding seismological observations, which provided the stepping-stone ideas on how to

Mihailo D. Trifunac

2009-01-01

104

Strong Ground Motion in the 2011 Tohoku Earthquake:1 a 1Directional -3Component Modeling2  

E-print Network

that has been well recorded in the near-fault zone. According to the53 Japanese database of the K1 Strong Ground Motion in the 2011 Tohoku Earthquake:1 a 1Directional - 3Component Modeling2 3 research aims at investigating seismic27 motion amplification in the 2011 Tohoku earthquake through a one

Boyer, Edmond

105

Simulation of Near-Fault Strong-Ground Motion Using Hybrid Green's Functions  

Microsoft Academic Search

The recently proposed hybrid Green's function method is designed to combine the advantages of both deterministic and stochastic approaches to simulating broadband ground motion when records of small events are not available. The method has the flexibility of incorporating complexities in the source, wave path, and local- site effects into strong ground motion simulations. In this article we analyze its

Arben Pitarka; Paul Somerville; Yoshimitsu Fukushima; Tomiichi Uetake; Kojiro Irikura

2000-01-01

106

Implications of the Northridge earthquake for strong ground motions from thrust faults  

USGS Publications Warehouse

The peak accelerations recorded on alluvial sites during the Northridge earthquake were about 50% larger than the median value predicted by current empirical attenuation relations at distances less than about 30 km. This raises the question of whether the ground motions from the Northridge earthquake are anomalous for thrust events or are representative of ground motions expected in future thrust earthquakes. Since the empirical data base contains few strong-motion records close to large-thrust earthquakes, it is difficult to assess whether the Northridge ground motions are anomalous based on recorded data alone. For this reason, we have used a broadband strong-motion simulation procedure to help assess whether the ground motions were anomalous. The simulation procedure has been validated against a large body of strong-motion data from California earthquakes, and so we expect it to produce accurate estimates of ground motions for any given rupture scenario, including blind-thrust events for which no good precedent existed in the strong-motion data base until the occurrence of the Northridge earthquake. The ground motions from the Northridge earthquake and our simulations of these ground motions have a similar pattern of departure from empirical attenuation relations for thrust earthquakes: the peak accelerations are at about the 84th percentile level for distances within 20 to 30 km and follow the median level for larger distances. This same pattern of departure from empirical attenuation relations was obtained in our simulations of the peak accelerations of an Elysian Park blind-thrust event prior to the occurrence of the Northridge earthquake. Since we are able to model this pattern with broadband simulations, and had done so before the Northridge earthquake occurred, this suggests that the Northridge strong-motion records are not anomalous and are representative of ground motions close to thrust faults. Accordingly, it seems appropriate to include these recordings in strong-motion data sets that are used to develop empirical ground-motion attenuation relations for thrust faults and to use this augmented data set as the basis for evaluating the need for modifications in design coefficients in the seismic provisions of building codes.

Somerville, P.; Saikia, C.; Wald, D.; Graves, R.

1996-01-01

107

The U.S. Army Corps of Engineers Seismic Strong-Motion Instrumentation Program  

Microsoft Academic Search

\\u000a The U.S. Army Corps of Engineers (USACE) currently operates a seismic Strong-Motion Instrumentation Program (SMIP) throughout\\u000a the United States to provide a measure of project performance, provide insight into the safety of USACE projects, and establish\\u000a a data base for earthquake research. Strong-motion instruments used for SMIP consist of digital and analog accelerographs,\\u000a peak acceleration recorders, and seismic alarm devices.

108

Estimation of strong ground motions from hypothetical earthquakes on the Cascadia subduction zone, Pacific Northwest  

Microsoft Academic Search

Strong ground motions are estimated for the Pacific Northwest assuming that large shallow earthquakes, similar to those experienced in southern Chile, southwestern Japan, and Colombia, may also occur on the Cascadia subduction zone. Fifty-six strong motion recordings for twenty-five subduction earthquakes ofMs=7.0 are used to estimate the response spectra that may result from earthquakesMwMw 9.5) is the largest event that

Thomas H. Heaton; Stephen H. Hartzell

1989-01-01

109

Estimation of strong ground motions from hypothetical earthquakes on the Cascadia subduction zone, Pacific Northwest  

Microsoft Academic Search

Strong ground motions are estimated for the Pacific Northwest assuming that large shallow earthquakes, similar to those experienced in southern Chile, southwestern Japan, and Colombia, may also occur on the Cascadia subduction zone. Fifty-six strong motion recordings for twenty-five subduction earthquakes of M s>=7.0 are used to estimate the response spectra that may result from earthquakes M w<81\\/4. Large variations

Thomas H. Heaton; Stephen H. Hartzell

1989-01-01

110

Strong-Motion Networks in Greece and Their Efficient Use in the Derivation of Regional Ground-Motion Prediction Models  

Microsoft Academic Search

\\u000a The destructive earthquakes that occurred over the last years in the broader Greek region urged the need for acquiring high\\u000a quality strong ground motion recordings. This necessity led to the enhancement of accelerographic networks by deploying a\\u000a significant number of new sensors all around Greece, improving their spatial coverage. Within the framework of this work,\\u000a a new, more efficient, strong

B. Margaris; A. Skarlatoudis; A. Savvaidis; N. Theodoulidis; I. Kalogeras; S. Koutrakis

111

Generation of Strong Motion Pulses during the 2011 Tohoku Earthquake and Their Modeling  

NASA Astrophysics Data System (ADS)

The 2011 Tohoku, Japan, earthquake is obviously the first M9 earthquake which was recorded by dense strong motion networks such as K-NET, etc. From engineering point of view, the most striking feature of strong ground motions of the earthquake is the generation of pulses. Strong ground motions in the frequency range from 0.2 to 1 Hz observed at many sites along the coast of Miyagi through Ibaraki Prefecture during the Tohoku earthquake are characterized by distinctive pulses. It is significantly important to consider the generation of such pulses in the strong-motion prediction for mega earthquakes, especially when the prediction is aimed at seismic design of structures. To model strong motion pulses from the Tohoku earthquake, a source model with rectangular subevents was newly developed for the earthquake. The locations of the subevents were determined from the arrival times. The sizes of the subevents were determined so that the width of the pulses can be reproduced appropriately. The constructed source model involves 9 subevents with relatively small size (on the order of several kilometers), located off-the-coast of Miyagi through off-the-coast of Ibaraki. The strong ground motions from the source model were calculated based on site amplification and phase characteristics (Nozu et al., 2006). The agreement between the observed and calculated ground motions was quite satisfactory, especially for velocity waveforms (0.2-1.0 Hz) including near-source pulses. Strong ground motions from the same earthquake have been modeled using a source model with SMGAs with a size of tens of kilometers (e.g., Kurahashi and Irikura, 2011; Satoh, 2011; Asano and Iwata, 2011; Kawabe et al., 2011). However, the relatively small width of the observed pulses requires smaller subevents. The small subevents used in the present study is, in essence, equivalent to the "super asperities" proposed by Matsushima and Kawase (2006) to explain strong motion pulses from the 1978 Miyagi-ken oki earthquake (Mw7.6). The author redefines the subevents as SPGAs (Strong-motion Pulse Generation Areas), because the definition of "asperity" itself is currently somewhat ambiguous. The observed strong motion pulses require a very high moment rate within a small area. The future work should be aimed at revealing the dynamics of SPGAs. The SPGA model for the 2011 Tohoku earthquake

Nozu, A.

2012-12-01

112

A study of residuals for strong ground motions in Adapazari basin, NW Turkey, by ground motion prediction equations (GMPEs)  

Microsoft Academic Search

The city of Adapazar? — located in the Marmara Region of northwest Turkey — is situated on a deep sedimentary basin and was\\u000a the city most heavily damaged by the strong ground motion of the 17 August 1999 Kocaeli earthquake (moment magnitude Mw = 7.4). This study determines site amplifications of the attenuation relationships for shallow earthquakes in the Adapazar?

Ergin Ulutas; Özkan Coruk; Ahmet Karakas

2011-01-01

113

Disaster Mitigation by Quick Response Against Strong Earthquake Motion  

NASA Astrophysics Data System (ADS)

The concept of EEW, earthquake early warning, was reported on San Francisco Daily Evening Bulletin on 3rd November 1868 by Dr. Cooper first for San Francisco area. According to him this idea was triggered by a failure of earthquake prediction. It is impressive that the thinking way is same as present. In 1982 more than 100 years later, the warning system for Tohoku Shinkansen realized the Cooper's idea for the first time on the world. After that, SAS for Mexico City started operating in 1991, and UrEDAS for Tokaido Shinkansen, an evolutional P-wave detection/warning system, began to operate in 1992. The UrEDAS technology is based on new concepts and methods to realize a real time system for estimating the earthquake parameters as magnitude, location and depth. In Japan at 1992, a new information service using UrEDAS technology had been prepared, but it was not born due to objection of JMA, Japan Meteorological Agency. By the same JMA, an information service, so called "Kinkyu Jishin Sokuho", will be broadcasted in nation wide from the first of October 2007. This implies that our UrEDAS Information Service plan has been correct, and it is my pleasure. However, it shall be rare case in Japan that JMA's information will reach faster than arriving of M7 class or less earthquake at the possible damaged areas, because it takes a time relatively long for processing and transmitting. Only for M8 class earthquakes of which the occurrence probability is about once in ten years in Japan, it is possible to receive the information before arriving of strong shaking in a possible damaged area far from the epicenter. JMA should popularize "Kinkyu Jishin Sokuho" after understandable explanation of these facts. I'm afraid that it will mislead people to broadcast a film on an evacuation training in unbelievable condition which is assuming an earthquake of seismic intensity 7 (corresponding to MMI scale XII) arriving 20 seconds later. Anyway, we can rely only on the onsite alarm in focal area. Accurate and quick earthquake information just after shaking is more useful than the late early warning. And I hope public organizations to make best effort that they can announce the earthquake information not only for main shock but also aftershocks, because these information is quite important for the quick response.

Nakamura, Y.

2007-12-01

114

``Strong'' ground motions in North America from the Bolivia earthquake of June 9, 1994 (Mw=8.3)  

Microsoft Academic Search

The Bolivia earthquake was remarkable for being felt in North America, as far as 8680 km from the epicenter. This paper examines the characteristics of ground motions in North America from the perspective of strong motion seismology. Data on ground motions is mostly from high-grain stations, but we also have two strong motion accelerograms. The largest accelerations and highest frequencies

John G. Anderson; Martha Savage; Roberto Quaas

1995-01-01

115

Estimation of strong ground motions from hypothetical earthquakes on the Cascadia subduction zone, Pacific Northwest  

USGS Publications Warehouse

Strong ground motions are estimated for the Pacific Northwest assuming that large shallow earthquakes, similar to those experienced in southern Chile, southwestern Japan, and Colombia, may also occur on the Cascadia subduction zone. Fifty-six strong motion recordings for twenty-five subduction earthquakes of Ms???7.0 are used to estimate the response spectra that may result from earthquakes Mw<81/4. Large variations in observed ground motion levels are noted for a given site distance and earthquake magnitude. When compared with motions that have been observed in the western United States, large subduction zone earthquakes produce relatively large ground motions at surprisingly large distances. An earthquake similar to the 22 May 1960 Chilean earthquake (Mw 9.5) is the largest event that is considered to be plausible for the Cascadia subduction zone. This event has a moment which is two orders of magnitude larger than the largest earthquake for which we have strong motion records. The empirical Green's function technique is used to synthesize strong ground motions for such giant earthquakes. Observed teleseismic P-waveforms from giant earthquakes are also modeled using the empirical Green's function technique in order to constrain model parameters. The teleseismic modeling in the period range of 1.0 to 50 sec strongly suggests that fewer Green's functions should be randomly summed than is required to match the long-period moments of giant earthquakes. It appears that a large portion of the moment associated with giant earthquakes occurs at very long periods that are outside the frequency band of interest for strong ground motions. Nevertheless, the occurrence of a giant earthquake in the Pacific Northwest may produce quite strong shaking over a very large region. ?? 1989 Birkha??user Verlag.

Heaton, T. H.; Hartzell, S. H.

1989-01-01

116

A Comprehensive Relocation of Earthquakes in Taiwan from 1991 to 2005  

E-print Network

Taiwan Strong-Motion Instrumentation Pro- gram (TSMIP) stations distributed throughout the island offshore events, especially around the subduction zone northeast of Taiwan. Thirdly, we adopted 3D VP-ground acceleration and epicentral distance, and (3) the geologically meaningful patterns of station corrections to P

Wu, Yih-Min

117

Latest Development of Real-Time Strong-Motion Monitoring System in Taiwan  

Microsoft Academic Search

Based on the experience of the 1999 Chi-Chi Earthquake, the Central Weather Bureau (CWB) has made substantial improvements to the earthquake rapid report system. Besides the current use of digital lease phone line and internet transmission, the satellite link for station to center is setup for backup. The station is also equipped with UPS to prevent the failure of electricity

N. Hsiao; Y. Wu; T. Shin; T. Teng

2003-01-01

118

Current Status of Strong-Motion Monitoring and Notification at the United States Bureau of Reclamation  

Microsoft Academic Search

\\u000a Acquisition of strong motion data at the Bureau of Reclamation provides near real time notification of strong shaking at our\\u000a structures as well as recordings of earthquakes for use in the dynamic analyses of large, engineered structures. To facilitate\\u000a rapid notification following strong ground shaking, we have developed a low-cost, automated system to retrieve event-triggered\\u000a seismic waveform data from digital

Chris Wood; Andy Viksne; Jon Ake; David Copeland

119

Magnitude estimation using the covered areas of strong ground motion in earthquake early warning  

E-print Network

network in Taiwan. Wu and Zhao [2006] showed that for earthquakes in southern California the attenuation, Taiwan, and southern California records. In the present EEW developments in Taiwan and southern in earthquake early warning TingLi Lin1 and YihMin Wu1 Received 3 February 2010; revised 12 March 2010; accepted

Wu, Yih-Min

120

Estimating coseismic deformations from near source strong motion records: methods and case studies  

Microsoft Academic Search

Digital strong-motion accelerographs have opened up the possibility of extracting ground motion characteristics at much lower\\u000a frequencies than was offered by analogue instruments. High-quality digital data obtained close to the faults have tempted\\u000a several efforts to retrieve permanent ground displacements after an earthquake. Such attempts have been partly successful,\\u000a and somewhat subjective, the main reason being the presence of baseline

R. Rupakhety; B. Halldorsson; R. Sigbjörnsson

2010-01-01

121

A strong-motion database from the Central American subduction zone  

Microsoft Academic Search

Subduction earthquakes along the Pacific Coast of Central America generate considerable seismic risk in the region. The quantification\\u000a of the hazard due to these events requires the development of appropriate ground-motion prediction equations, for which purpose\\u000a a database of recordings from subduction events in the region is indispensable. This paper describes the compilation of a\\u000a comprehensive database of strong ground-motion

Maria Cristina Arango; Fleur O. Strasser; Julian J. Bommer; Douglas A. Hernández; Jose M. Cepeda

2011-01-01

122

Ground Motion Characteristics and Source Process of the 2002 Denali Earthquake Inferred from the Strong Motion Records  

NASA Astrophysics Data System (ADS)

The 2002 Denali earthquake, which occurred at the Denali Fault System in Alaska on 3 November, 2003, was one of the largest inland earthquakes all over the world. The Denali Fault System extends for more than 2000 km across south-central Alaska, Yukon Territory, northern British Columbia and southeastern Alaska (Lanphere, 1978). In this time the rupture started on the Susitna Glacier Fault with thrust motion, propagated eastward along the Denali Fault with right-lateral movement, and terminated on the Totschunda Fault (Fuis and Wald, 2003). From the particle motion at a strong motion site PS10 (pump station #10 of Trans Alaska Pipeline), which is located at about 3 km distance from the fault, we could recognize a significant phase with fault-parallel movement before fault-normal motions. This motion shows the fault displacement in front of PS10. We have also checked the orientation of seismometer at PS10 with visiting the place in this summer. Therefore, the sense of ground motion at PS10 is reliable. Comparing the observed and calculated travel time of this phase, the average rupture propagation velocity between the rupture starting point and a sub-fault in front of PS10 was estimated to be 2700 m/s. However, it does not deny the possibility of supershear rupture on a certain portion of source area, so that we need to examine carefully the rupture velocity during the rupture. Whole source process was investigated with the multi-time window kinematic waveform inversion (Hartzell and Heaton, 1983; Sekiguchi et al., 2000). A 1-D laterally homogeneous underground structure model was assumed based on the result of refraction and wide-angle reflection survey by Beaudoin et al. (1992). Green's functions were calculated using the discrete wavenumber method (Bouchon, 1981) together with the reflection transmission matrix method (Kennett and Kerry, 1979). Spatio-time smoothing and slip constraints as pure-dip to right-lateral slip for Susitna Glacier fault, right-lateral +/- 45 ° slip for other faults, were included (Sekiguchi et al., 2000). The appropriate strength of smoothing constraint was evaluated using Akaike's Bayesian Information Criterion (Akaike, 1980). Three components of velocity waveforms obtained at 10 strong motion stations including PS10 were inverted. We tried to include the detailed information of the surface displacement distributions compiled by Eberhart-Phillips et al. (2003) as constraint information in our analysis to make up the insufficiency of strong motion data. We could reproduce observed ground motion in low-frequency range (0.1-0.5 Hz for Alyeska stations, 0.05-0.5 Hz for others) based on the source model obtained by the inversion analysis. The inversion result showed that the ground motion at PS10 was mainly controlled by the nearest asperity. Large slips on the fault from the inversion result were observed at about 90 km east and about 170 km east from the epicenter. We are grateful to United States Geological Survey, University of Alaska, and Alyeska Pipeline Service Company for releasing digital strong motion records and to Alaska Earthquake Information Center for which we retrieved hypocentral information.

Asano, K.; Iwata, T.; Irikura, K.

2003-12-01

123

Characteristics of the Strong Ground Motions from the 23 October 2011 Van earthquake, Turkey  

NASA Astrophysics Data System (ADS)

The recent 23 October 2011 Mw 7.1 Van Earthquake occurred at 13:41 local time in Eastern Turkey with an epicenter at 43.36oE, 38.76oN (KOERI) caused severe damage in the epicenter area. Intenseve aftershocks followed, activating the several previously unknown small scale faults around the main fault rupture. Twenty-two accelerometric stations belonging to the National Strong Ground Motion Network (operated by the Earthquake Department of the Disaster and Emergency Management Presidency, AFAD) and eleven accelerometric stations of the Iranian Strong Motion Network (ISMN) recorded the main shock. In this study a great effort has been directed towards understanding the characteristics of ground motion associated with the Van Lake seismic sequences. In this respect we study the features of the strong ground motion recordings obtained during the main shock by means of the spatial variations of the peak ground accelerations and peak ground velocities, and the spectral accelerations (5% of critical damping) together with the site amplifications. High frequency ground motion stochastic simulations are performed in the near-fault area and compared with the empirical Ground Motion Prediction Equations (GMPEs). Finally, regarding the October-November Van earthquake sequence, a static analysis of the Coulomb Failure Function variation is carried out adopting the slip distributions retrieved by USGS (Hayes, 2011).

Akinci, A.; Antonioli, A.

2012-12-01

124

Shear-wave velocity compilation for Northridge strong-motion recording sites  

USGS Publications Warehouse

Borehole and other geotechnical information collected at the strong-motion recording sites of the Northridge earthquake of January 17, 1994 provide an important new basis for the characterization of local site conditions. These geotechnical data, when combined with analysis of strong-motion recordings, provide an empirical basis to evaluate site coefficients used in current versions of US building codes. Shear-wave-velocity estimates to a depth of 30 meters are derived for 176 strong-motion recording sites. The estimates are based on borehole shear-velocity logs, physical property logs, correlations with physical properties and digital geologic maps. Surface-wave velocity measurements and standard penetration data are compiled as additional constraints. These data as compiled from a variety of databases are presented via GIS maps and corresponding tables to facilitate use by other investigators.

Borcherdt, Roger D.; Fumal, Thomas E.

2002-01-01

125

Strong Motion Instrumentation of Seismically-Strengthened Port Structures in California by CSMIP  

USGS Publications Warehouse

The California Strong Motion Instrumentation Program (CSMIP) has instrumented five port structures. Instrumentation of two more port structures is underway and another one is in planning. Two of the port structures have been seismically strengthened. The primary goals of the strong motion instrumentation are to obtain strong earthquake shaking data for verifying seismic analysis procedures and strengthening schemes, and for post-earthquake evaluations of port structures. The wharves instrumented by CSMIP were recommended by the Strong Motion Instrumentation Advisory Committee, a committee of the California Seismic Safety Commission. Extensive instrumentation of a wharf is difficult and would be impossible without the cooperation of the owners and the involvement of the design engineers. The instrumentation plan for a wharf is developed through study of the retrofit plans of the wharf, and the strong-motion sensors are installed at locations where specific instrumentation objectives can be achieved and access is possible. Some sensor locations have to be planned during design; otherwise they are not possible to install after construction. This paper summarizes the two seismically-strengthened wharves and discusses the instrumentation schemes and objectives. ?? 2009 ASCE.

Huang, M. J.; Shakal, A. F.

2009-01-01

126

Estimation of Strong Ground Motions in Southwest Western Australia with a Combined Green's Function and Stochastic Approach  

Microsoft Academic Search

As only a very limited number of earthquake strong ground motion records are available in southwest Western Australia (SWWA), it is difficult to derive a reliable and unbiased strong ground motion attenuation model based on these data. To overcome this, in this study a combined approach is used to simulate ground motions. First, the stochastic approach is used to simulate

Jonathan Z. Liang; Hong Hao; Brian A. Gaull; Cvetan Sinadinovski

2008-01-01

127

On Drift Effects in Velocity and Displacement of Greek Uncorrected Digital Strong Motion Data  

Microsoft Academic Search

Fifty years after the first installation of analog accelerographs, digital instruments recording the strong-motion came in operation. Their advantages comparing to the analog ones are obvious and they have been described in detail in several works. Nevertheless it has been pointed out that velocity and displacement values derived from several accelerograms, recorded in various strong earthquakes worldwide (e.g. 1999 Chi-Chi,

A. Skarlatoudis; B. Margaris

2005-01-01

128

THE EMILIA THRUST EARTHQUAKE OF 20 MAY 2012 (NORTHERN ITALY): STRONG MOTION AND GEOLOGICAL OBSERVATIONS  

E-print Network

1 THE EMILIA THRUST EARTHQUAKE OF 20 MAY 2012 (NORTHERN ITALY): STRONG MOTION AND GEOLOGICAL INTRODUCTION On 20 May 2012, at 02:03:53 (UTC), Northern Italy was struck by an earthquake of magnitude Ml 5 with Ml 4.8. Eleven events with magnitude 4.0 Ml 4.5, plus several other minor earthquakes, occurred

Fleskes, Joe

129

Simulation of strong earthquake motion by explosions — experiments at the Lyaur testing range in Tajikistan  

Microsoft Academic Search

Strong motion data of 10 controlled explosion experiments conducted in 1977 at the Lyaur testing range in the Republic of Tajikistan are revisited. The explosions were detonated in arrays, with time delay between detonation of array lines. Ground accelerations, as large as ?1.6g, were recorded at 4 sites by SMA-1 accelerographs. The records were recently digitized and processed with modern

S. Kh. Negmatullaev; M. I. Todorovska; M. D. Trifunac

1999-01-01

130

Design and development of a low-cost, high-performance, strong-motion accelerograph  

Microsoft Academic Search

This paper outlines the conception, design and development of the CUSP accelerograph system. The CUSP accelerograph provides a cheap strong-motion specific instrument that fulfils the requirements of the earthquake engineering community without the high cost penalty associated with purchasing the unwanted resolution of a sensitive seismograph.

H. R. Avery; J. B. Berrill; M. B. Dewe

131

STRONG MOTION DATA PROCESSING AND RECORDING AT UNIVERSITY OF SOUTHERN CALIFORNIA  

Microsoft Academic Search

A brief review is presented of the Los Angeles and Vicinity Strong Motion Network operated by the University of Southern California (USC), consisting of 80 stations deployed in 1978-1980, and of software developed and used at USC for digitization of accelerograms recorded on film, and for routine and specialized data processing of digitized or digitally recorded accelerograms. The currently used

MARIA I. TODOROVSKA; VINCENT W. LEE

132

CURRENT STATUS OF STRONG-MOTION EARTHQUAKE OBSERVATION IN JAPANESE PORTS  

Microsoft Academic Search

Strong ground motions and the response of structures have been observed in the major ports in Japan for more than 40 years. The network now covers the entire coastline of Japan with 110 accelerographs in 60 ports. This article describes the current status of the network, some findings from recent observations and data availability.

Atsushi NOZU

133

Shallow shear wave velocity and Q structures at the El Centro strong motion accelerograph array  

Microsoft Academic Search

At three sites in the U.S. Geological Survey El Centro Strong Motion Accelerograph Array (EO5, EO6 and EO7), we have used the dispersive and attenuative properties of artificially generated Rayleigh waves to infer the depth dependence of shear wave velocity (?) and quality factor (Q) and a site dependent equivalent elastic source spectrum. This approach provides an inexpensive means for

Terrance G. Barker; Jeffry L. Stevens

1983-01-01

134

Simulation of strong earthquake motion by explosions — experiments at the Lyaur testing range in Tajikistan  

Microsoft Academic Search

Strong motion data of 10 controlled explosion experiments conducted in 1977 at the Lyaur testing range in the Republic of Tajikistan are revisited. The explosions were detonated in arrays, with time delay between detonation of array lines. Ground accelerations, as large as , 1.6g, were recorded at 4 sites by SMA-1 accelerographs. The records were recently digitized and processed with

S. Kh; M. D. Trifunac

135

ON THE CORRELATION OF SEISMIC INTENSITY SCALES WITH THE PEAKS OF RECORDED STRONG .GROUND MOTION  

Microsoft Academic Search

Correlations of the recorded peak acceleration, velocity and displacement, and the Modified Mercalli intensity have been carried out for 57 earthquakes and 187 strong-motion accelerograms recorded in the Western United States. Correlations of peak acceleration with intensity, characterized by the data scatter exceeding one order of magnitude, have lead to average peak accelerations which are higher than those reported by

M. D. TRIFUNAC; A. G. BRADY

1975-01-01

136

The main features of data processing procedure for strong-motion records in China  

Microsoft Academic Search

The main features of strong-motion data processing procedures used in China are as follows: the effect of the record length on the level of digitizing noise background is considered; a different method is suggested for digitizing and connecting the successive sections of those long duration records requiring repositioning on the digitizer table; the method for instrument correction at both high

Lili Xie

1985-01-01

137

SOME OBSERVATIONS ON STRONG-MOTION EARTHQUAKE MEASUREMENT USING A DIGITAL ACCELEROGRAPH  

Microsoft Academic Search

This paper presents results of a study of some of the characteristics of a PDR-1 digital strong-motion accelerograph. Results are presented for laboratory tests of the background noise level of the instrument, and these results are compared with previously reported observations for optical instruments. Noise levels for the digital instrument are found to be one or two orders of magnitude

WILFRED D. IWAN; MICHAEL A. MOSER; CHIA-YEN PENG

138

A composite source model for computing realistic synthetic strong ground motions  

Microsoft Academic Search

A composite source model is presented for convolution with synthetic Green's functions, in order to synthesize strong ground motions due to a complex rupture process of a large earthquake. Subevents with a power-law distribution of sizes are located randomly on the fault. Each subevent radiates a displacement pulse with the shape of a Brune's pulse in the far field, at

Yuehua Zeng; John G. Anderson; Guang Yu

1994-01-01

139

Strong Earthquake Motion Estimates for Three Sites on the U.C. Riverside Campus  

Microsoft Academic Search

The approach of the Campus Earthquake Program (CEP) is to combine the substantial expertise that exists within the UC system in geology, seismology, and geotechnical engineering, to estimate the earthquake strong motion exposure of UC facilities. These estimates draw upon recent advances in hazard assessment, seismic wave propagation modeling in rocks and soils, and dynamic soil testing. The UC campuses

R. Archuleta; A. Elgamal; F. Heuze; T. Lai; D. Lavalle; B. Lawrence; P. C. Liu; L. Matesic; M. Riemar; J. Steidl; M. Vucetic; J. Wagoner; Z. Yang

2000-01-01

140

Super-Brownian motion as the unique strong solution to an SPDE  

E-print Network

A stochastic partial differential equation (SPDE) is derived for super-Brownian motion regarded as a distribution function valued process. The strong uniqueness for the solution to this SPDE is obtained by an extended Yamada-Watanabe argument. Similar results are also proved for Fleming-Viot process.

Xiong, Jie

2012-01-01

141

Empirical predictive model for the vmax/ amax ratio of strong ground motions using genetic programming  

NASA Astrophysics Data System (ADS)

Earthquake-induced deformation of structures is strongly influenced by the frequency content of input motion. Nevertheless, state-of-the-practice studies commonly use the intensity measures such as peak ground acceleration ( PGA), which are not frequency dependent. The vmax/ amax ratio of strong ground motions can be used in seismic hazard studies as a parameter that captures the influence of frequency content. In the present study, genetic programming (GP) is employed to develop a new empirical predictive equation for the vmax/ amax ratio of the shallow crustal strong ground motions recorded at free field sites. The proposed model is a function of earthquake magnitude, closest distance from source to site ( Rclstd), faulting mechanism, and average shear wave velocity over the top 30 m of site ( Vs30 ). A wide-ranging database of strong ground motion released by Pacific Earthquake Engineering Research Center (PEER) was utilized. It is demonstrated that residuals of the final equation show insignificant bias against the variations of the predictive parameters. The results indicate that vmax/ amax increases through increasing earthquake magnitude and source-to-site distance while magnitude dependency is considerably more than distance dependency. In addition, the proposed model predicts higher vmax/ amax ratio at softer sites that possess higher fundamental periods. Consequently, as an instance for the application of the proposed model, its reasonable performance in liquefaction potential assessment of sands and silty sands is presented.

Jafarian, Yaser; Kermani, Elnaz; Baziar, Mohammad H.

2010-12-01

142

Kinematic analysis of strong motion P and SV waves from the sterling event  

Microsoft Academic Search

P and SV velocity waveforms from the Sterling explosion of December 3, 1966, are analyzed from a point of view often taken in earthquake source studies. The detonation occurred in the cavity excavated by the Salmon explosion within the Tatum salt dome, Mississippii, Velocity recordings taken from nearby borehole strong motion instruments show the occurrence of significant SV energy (Perret,

Charles A. Langston

1983-01-01

143

Renewal of K-NET (National Strong-motion Observation Network of Japan)  

NASA Astrophysics Data System (ADS)

The National Research Institute for Earth Science and Disaster Prevention (NIED) operates K-NET (Kyoshin Network), the national strong-motion observation network, which evenly covers the whole of Japan at intervals of 25 km on average. K-NET was constructed after the Hyogoken-Nambu (Kobe) earthquake in January 1995, and began operation in June 1996. Thus, eight years have passed since K-NET started, and large amounts of strong-motion records have been obtained. As technology has progressed and new technologies have become available, NIED has developed a new K-NET with improved functionality. New seismographs have been installed at 443 observatories mainly in southwestern Japan where there is a risk of strong-motion due to the Nankai and Tonankai earthquakes. The new system went into operation in June 2004, although seismographs have still to be replaced in other areas. The new seismograph (K-NET02) consists of a sensor module, a measurement module and a communication module. A UPS, a GPS antenna and a dial-up router are also installed together with a K-NET02. A triaxial accelerometer, FBA-ES-DECK (Kinemetrics Inc.) is built into the sensor module. The measurement module functions as a conventional strong-motion seismograph for high-precision observation. The communication module can perform sophisticated processes, such as calculation of the Japan Meteorological Agency (JMA) seismic intensity, continuous recording of data and near real-time data transmission. It connects to the Data Management Center (DMC) using an ISDN line. In case of a power failure, the measurement module can control the power supply to the router and the communication module to conserve battery power. One of the main features of K-NET02 is a function for processing JMA seismic intensity. K-NET02 functions as a proper seismic intensity meter that complies with the official requirements of JMA, although the old strong-motion seismograph (K-NET95) does not calculate seismic intensity. Another feature is near real-time data transmission. When a K-NET02 detects a strong-motion, it can automatically connect to the DMC in 2 to 5 seconds and then transmits seismic data. Furthermore, the full-scale is improved from 2000 gals to 4000 gals and the dynamic range of AD conversion is more than 132 dB. Strong-motion records of the new K-NET are available at: http://www.kyoshin.bosai.go.jp/

Kunugi, T.; Fujiwara, H.; Aoi, S.; Adachi, S.

2004-12-01

144

Comparisons of ground motions from five aftershocks of the 1999 Chi-Chi, Taiwan, earthquake with empirical predictions largely based on data from California  

USGS Publications Warehouse

The observed ground motions from five large aftershocks of the 1999 Chi-Chi, Taiwan, earthquake are compared with predictions from four equations based primarily on data from California. The four equations for active tectonic regions are those developed by Abrahamson and Silva (1997), Boore et al. (1997), Campbell (1997, 2001), and Sadigh et al. (1997). Comparisons are made for horizontal-component peak ground accelerations and 5%-damped pseudoacceleration response spectra at periods between 0.02 sec and 5 sec. The observed motions are in reasonable agreement with the predictions, particularly for distances from 10 to 30 km. This is in marked contrast to the motions from the Chi-Chi mainshock, which are much lower than the predicted motions for periods less than about 1 sec. The results indicate that the low motions in the mainshock are not due to unusual, localized absorption of seismic energy, because waves from the mainshock and the aftershocks generally traverse the same section of the crust and are recorded at the same stations. The aftershock motions at distances of 30-60 km are somewhat lower than the predictions (but not nearly by as small a factor as those for the mainshock), suggesting that the ground motion attenuates more rapidly in this region of Taiwan than it does in the areas we compare with it. We provide equations for the regional attenuation of response spectra, which show increasing decay of motion with distance for decreasing oscillator periods. This observational study also demonstrates that ground motions have large earthquake-location-dependent variability for a specific site. This variability reduces the accuracy with which an earthquake-specific prediction of site response can be predicted. Online Material: PGAs and PSAs from the 1999 Chi-Chi earthquake and five aftershocks.

Wang, G. -Q.; Boore, D. M.; Igel, H.; Zhou, X. -Y.

2004-01-01

145

Synthesis of strong motions by using an aftershock record as the Green's function  

NASA Astrophysics Data System (ADS)

A method to synthesize strong ground motions by using aftershock records as Green's functions was developed to reproduce the high-frequency components of the main shock. We call it a random slip model, and have applied it to three large earthquakes, the east off-Izu Peninsula earthquake of 1980 ( M = 6.7), the off-Urakawa earthquake of 1982 ( M = 7.1) and the Central Japan Sea earthquake of 1983 ( M = 7.7). Seismic intensities at six stations during the earthquakes analyzed here were from I to VI on the JMA (Japan Meteorological Agency) scale. All the aftershock seismograms used as Green's functions in the present study were recorded by velocity-type strong-motion seismographs with a large dynamic range over a wide frequency range. A few main-shock seismograms were recorded by seismographs similar to those mentioned above; the rest were recorded by other types of strong-motion seismographs e.g. the SMAC (strong-motion accelerograph) and JMA strong-motion seismographs. From a comparison of the synthetic with the observed seismograms of the main shock, we conclude the following: (1) Using the record of an adequate aftershock and an adequate source model, we can satisfactorily reproduce any observed seismogram of the main shock. (2) The conditions for an adequate aftershock are that the hypocenter is located in the central part of the main-shock fault, and that the mechanism is similar to that of the main shock. (3) The high-frequency waves contained in the main-shock seismograms are reproduced by the random slip model up to 5 Hz for records at every station. (4) By considering a multiple-shock source model, we can fit the synthetic to the observed seismograms for two large earthquakes with magnitudes ( Mj) larger than 7.

Murumatu, I.; Ohnuma, H.

1988-06-01

146

Observations and Modeling of Strong Ground Motions for the 9 October 1995 Mw 8 ColimaJalisco, Mexico, Earthquake  

E-print Network

Observations and Modeling of Strong Ground Motions for the 9 October 1995 Mw 8 Colima improvement in the hazard estimates depends on the urgent deployment of seismological and strong ground motion of the Mw 8 1995 mainshock. Based on the comparisons of the BB synthetics with the observed strong ground

Olsen, Kim Bak

147

Hanford strong motion accelerometer network: A summary of the first year of operation  

SciTech Connect

The Hanford Seismic Monitoring Network consists of two designs of equipment and sites: seismometer sites and strong motion accelerometer (SMA) sites. Seismometer sites are designed to locate earthquakes on and near the Hanford Site and determine their magnitude and hypocenter location. The US Department of Energy (DOE) Order 5480.28, Natural Phenomena Hazards (DOE 1993) requires that facilities or sites that have structures or components in Performance Category 2 with hazardous material, and all Performance Category 3 and 4 facilities shall have instrumentation or other means to detect and record the occurrence and severity of seismic events. In order to comply with DOE Order 5480.28, the Hanford Seismic Monitoring Network seismometer sites needed to be complemented with strong motion accelerometers to record the ground motion at specific sites. The combined seismometer sites and strong motion accelerometer sites provide the Hanford Site with earthquake information to comply with DOE Order 5480.28. The data from these instruments will be used by the PHMC staff to assess the damage to facilities following a significant earthquake.

Conrads, T.J.

1997-09-22

148

New Hybridized Surface Wave Approach for Geotechnical Modeling of Shear Wave Velocity at Strong Motion Recording Stations  

NASA Astrophysics Data System (ADS)

Strong motion recording (SMR) networks often have little or no shear wave velocity measurements at stations where characterization of site amplification and site period effects is needed. Using the active Spectral Analysis of Surface Waves (SASW) method, and passive H/V microtremor method we have investigated nearly two hundred SMR sites in California, Alaska, Japan, Australia, China and Taiwan. We are conducting these studies, in part, to develop a new hybridized method of site characterization that utilizes a parallel array of harmonic-wave sources for active-source SASW, and a single long period seismometer for passive-source microtremor measurement. Surface wave methods excel in their ability to non-invasively and rapidly characterize the variation of ground stiffness properties with depth below the surface. These methods are lightweight, inexpensive to deploy, and time-efficient. They have been shown to produce accurate and deep soil stiffness profiles. By placing and wiring shakers in a large parallel circuit, either side-by-side on the ground or in a trailer-mounted array, a strong in-phase harmonic wave can be produced. The effect of arraying many sources in parallel is to increase the amplitude of waves received at far-away spaced seismometers at low frequencies so as to extend the longest wavelengths of the captured dispersion curve. The USGS system for profiling uses this concept by arraying between two and eight electro-mechanical harmonic-wave shakers. With large parallel arrays of vibrators, a dynamic force in excess of 1000 lb can be produced to vibrate the ground and produce surface waves. We adjust the harmonic wave through a swept-sine procedure to profile surface wave dispersion down to a frequency of 1 Hz and out to surface wave-wavelengths of 200-1000 meters, depending on the site stiffness. The parallel-array SASW procedure is augmented using H/V microtremor data collected with the active source turned off. Passive array microtremor data reveal the natural and resonance characteristics of the ground by capturing persistent natural vibrations. These microtremors are the result of the interaction of surface waves arriving from distant sources and the stiffness structure of the site under investigation. As such, these resonance effects are effective in constraining the layer thicknesses of the SASW shear wave velocity structure and aid in determining the depth of the deepest layer. Together, the hybridized SASW and H/V procedure provides a complete data set for modeling the geotechnical aspects of ground amplification of earthquake motions. Data from these investigations are available at http://walrus.wr.usgs.gov/geotech.

Kayen, R.; Carkin, B.; Minasian, D.

2006-12-01

149

Brownian motion in strongly coupled, anisotropic Yang-Mills plasma: A holographic approach  

NASA Astrophysics Data System (ADS)

We employ methods of gauge/string duality to analyze the nonrelativistic Brownian motion and the concomitant Langevin equation of a heavy quark in a strongly coupled, thermal, anisotropic Yang-Mills plasma in the low anisotropy limit. We consider fluctuations both along and perpendicular to the direction of anisotropy and study the effects of anisotropy on the drag coefficient, the diffusion constant, and the Langevin coefficient for both the directions. We also verify the fluctuation-dissipation theorem for Brownian motion in an anisotropic medium.

Chakrabortty, Shankhadeep; Chakraborty, Somdeb; Haque, Najmul

2014-03-01

150

Comparison of damping in buildings under low-amplitude and strong motions  

USGS Publications Warehouse

This paper presents a comprehensive assessment of damping values and other dynamic characteristics of five buildings using strong-motion and low-amplitude (ambient vibration) data. The strong-motion dynamic characteristics of five buildings within the San Francisco Bay area are extracted from recordings of the 17 October 1989 Loma Prieta earthquake (LPE). Ambient vibration response characteristics for the same five buildings were inferred using data collected in 1990 following LPE. Additional earthquake data other than LPE for one building and ambient vibration data collected before LPE for two other buildings provide additional confirmation of the results obtained. For each building, the percentages of critical damping and the corresponding fundamental periods determined from low-amplitude test data are appreciably lower than those determined from strong-motion recordings. These differences are attributed mainly to soil-structure interaction and other non-linear behavior affecting the structures during strong shaking. Significant contribution of radiation damping to the effective damping of a specific building is discussed in detail.

Celebi, M.

1996-01-01

151

Analysis of Strong Motion Records of Turkey Earthquakes for the Period of 1999-2006  

NASA Astrophysics Data System (ADS)

The strong motion records of 21 events with magnitudes of M>5.0 occurred in Turkey in the period of 1999 - 2006 have been analyzed within the EU-FP6 NERIES Project NA5 Workpackage. A software package called PARAMACC_Ver8.0 has been developed within the NA5 workgroup. The code analyses the ground motion, applies filtering to the accelerometer and obtains response spectra, the parameters of record duration, corrected PGA, Arias Intensity, Trifunac Duration, Cumulative Absolute Velocity, Pseudo-velocity Response Spectrum, Housner Intensity, and PGV. The recorded ground motions and calculated parameters are stored in an archive for further analysis. It is intended to increase the number of analysed events and keep them in the archive for the further analysis, which will be helpful to develop empirical relations for Turkey earthquakes.

Zulfikar, C.; Durukal, E.; Erdik, M.

2009-04-01

152

Chapter A. The Loma Prieta, California, Earthquake of October 17, 1989 - Strong Ground Motion  

USGS Publications Warehouse

Strong ground motion generated by the Loma Prieta, Calif., earthquake (MS~7.1) of October 17, 1989, resulted in at least 63 deaths, more than 3,757 injuries, and damage estimated to exceed $5.9 billion. Strong ground motion severely damaged critical lifelines (freeway overpasses, bridges, and pipelines), caused severe damage to poorly constructed buildings, and induced a significant number of ground failures associated with liquefaction and landsliding. It also caused a significant proportion of the damage and loss of life at distances as far as 100 km from the epicenter. Consequently, understanding the characteristics of the strong ground motion associated with the earthquake is fundamental to understanding the earthquake's devastating impact on society. The papers assembled in this chapter address this problem. Damage to vulnerable structures from the earthquake varied substantially with the distance from the causative fault and the type of underlying geologic deposits. Most of the damage and loss of life occurred in areas underlain by 'soft soil'. Quantifying these effects is important for understanding the tragic concentrations of damage in such areas as Santa Cruz and the Marina and Embarcadero Districts of San Francisco, and the failures of the San Francisco-Oakland Bay Bridge and the Interstate Highway 880 overpass. Most importantly, understanding these effects is a necessary prerequisite for improving mitigation measures for larger earthquakes likely to occur much closer to densely urbanized areas in the San Francisco Bay region. The earthquake generated an especially important data set for understanding variations in the severity of strong ground motion. Instrumental strong-motion recordings were obtained at 131 sites located from about 6 to 175 km from the rupture zone. This set of recordings, the largest yet collected for an event of this size, was obtained from sites on various geologic deposits, including a unique set on 'soft soil' deposits (artificial fill and bay mud). These exceptional ground-motion data are used by the authors of the papers in this chapter to infer radiation characteristics of the earthquake source, identify dominant propagation characteristics of the Earth?s crust, quantify amplification characteristics of near-surface geologic deposits, develop general amplification factors for site-dependent building-code provisions, and revise earthquake-hazard assessments for the San Francisco Bay region. Interpretations of additional data recorded in well-instrumented buildings, dams, and freeway overpasses are provided in other chapters of this report.

Borcherdt, Roger D.

1994-01-01

153

Updating Newmark Displacement Empirical Formula with the Chi-Chi Earthquake Strong-Motion Data.  

NASA Astrophysics Data System (ADS)

The cumulative displacement is an effective approach to measure the stability of a natural slope under the shocking of earthquake. The Newmark's method helps to calculate the co-seismic relative cumulative displacement of a sliding block by integrating the acceleration time history data of a strong-motion record. It may also be estimated by applying an empirical equation, like the Jibson's formula. This research employs strong motion data of the Chi-Chi main shock and five larger aftershocks and other worldwide data to find out the relationship among critical acceleration (Ac)} Arias Intensity (Ia), and Newmark displacement (Dn). The result revealed that the form of the Jibson's formula should be modified. A new relationship for estimation of Dn from Ia and Ac is proposed and the improvement is discussed.

Hsieh, S.; Lee, C.; Lin, P.

2005-12-01

154

Vision for the Future of the US National Strong-Motion Program  

USGS Publications Warehouse

This document provides the requested vision for the future of the National Strong-Motion Program operated by the US Geological Survey. Options for operation of the program are presented in a companion document. Each of the three major charges of the EHRP, program council pertaining to the vision document is addressed here. The 'Vision Summary' through a series of answers to specific questions is intended to provide a complete synopsis of the committees response to program council charges. The Vision for the Future of the NSMP is presented as section III of the Summary. Analysis and detailed discussion supporting the answers in the summary are presented as sections organized according to the charges of the program council. The mission for the program is adopted from that developed at the national workshop entitled 'Research Needs for Strong Motion Data to Support Earthquake Engineering' sponsored by the National Science Foundation.

1997-01-01

155

A composite source model for computing realistic synthetic strong ground motions  

NASA Astrophysics Data System (ADS)

A composite source model is presented for convolution with synthetic Green's functions, in order to synthesize strong ground motions due to a complex rupture process of a large earthquake. Subevents with a power-law distribution of sizes are located randomly on the fault. Each subevent radiates a displacement pulse with the shape of a Brune's pulse in the far field, at a time determined by a constant rupture velocity propagating from the hypocenter. Thus, all the input parameters have a physical basis. We simulate strong ground motions for event - station pairs that correspond to records obtained in Mexico by the Guerrero accelerograph network. The synthetic accelerations, velocities, and displacements have realistic amplitudes, durations, and Fourier spectra.

Zeng, Yuehua; Anderson, John G.; Yu, Guang

1994-04-01

156

Before and after retrofit - response of a building during ambient and strong motions  

USGS Publications Warehouse

This paper presents results obtained from ambient vibration and strong-motion responses of a thirteen-story, moment-resisting steel framed Santa Clara County Office Building (SCCOB) before being retrofitted by visco-elastic dampers and from ambient vibration response following the retrofit. Understanding the cumulative structural and site characteristics that affect the response of SCCOB before and after the retrofit is important in assessing earthquake hazards to other similar buildings and decision making in retrofitting them. The results emphasize the need to better evaluate structural and site characteristics in developing earthquake resisting designs that avoid resonating effects. Various studies of the strong-motion response records from the SCCOB during the 24 April 1984 (MHE) Morgan Hill (MS = 6.1), the 31 March 1986 (MLE) Mt. Lewis (MS = 6.1) and the 17 October 1989 (LPE) Loma Prieta (MS = 7.1) earthquakes show that the dynamic characteristics of the building are such that it (a) resonated (b) responded with a beating effect due to close-coupling of its translational and torsional frequencies, and (c) had a long-duration response due to low-damping. During each of these earthquakes, there was considerable contents damage and the occupants felt the rigorous vibration of the building. Ambient tests of SCCOB performed following LPE showed that both translational and torsional periods of the building are smaller than those derived from strong motions. Ambient tests performed following the retrofit of the building with visco-elastic dampers show that the structural fundamental mode frequency of the building has increased. The increased frequency implies a stiffer structure. Strong-motion response of the building during future earthquakes will ultimately validate the effectiveness of the retrofit method.This paper presents results obtained from ambient vibration and strong-motion responses of a thirteen-story, moment-resisting steel framed Santa Clara County Office Building (SCCOB) before being retrofitted by visco-elastic dampers and from ambient vibration response following the retrofit. Understanding the cumulative structural and site characteristics that affect the response of SCCOB before and after the retrofit is important in assessing earthquake hazards to other similar buildings and decision making in retrofitting them. The results emphasize the need to better evaluate structural and site characteristics in developing earthquake resisting designs that avoid resonating effects. Various studies of the strong-motion response records from the SCCOB during the 24 April 1984 (MHE) Morgan Hill (Ms = 6.1), the 31 March 1986 (MLE) Mt. Lewis (Ms = 6.1) and the 17 October 1989(LPE) Loma Prieta (Ms = 7.1) earthquakes show that the dynamic characteristics of the building are such that it (a) resonated (b) responded with a beating effect due to close-coupling of its translational and torsional frequencies, and (c) had a long-duration response due to low-damping. During each of these earthquakes, there was considerable contents damage and the occupants felt the rigorous vibration of the building. Ambient tests of SCCOB performed following LPE showed that both translational and torsional periods of the building are smaller than those derived from strong motions. Ambient tests performed following the retrofit of the building with visco-elastic dampers show that the structural fundamental mode frequency of the building has increased. The increased frequency implies a stiffer structure. Strong-motion response of the building during future earthquakes will ultimately validate the effectiveness of the retrofit method.

Celebi, M.; Liu, H.-P.

1998-01-01

157

Shear-wave velocity profile at the Texcoco strong-motion array site, Valley of Mexico  

Microsoft Academic Search

The shear-wave velocity profile at the Texcoco strong motion accelerograph array site was evaluated down to 39 m using Seismic Cone Penetrometry (SCPT). The hard layer from 28 m to 29 m was drilled to allow penetration to greater depths. The results are compared with those obtained from shear-wave reflection\\/refraction, and from the inversion of microtremor data. All the studies

Bill Stephenson; Cinna Lomnitz

2005-01-01

158

A Note of the Accuracy of Computed Ground Displacements from Strong-Motion Accelerogram  

Microsoft Academic Search

ABSTRACT In this paper the accuracy of routine methods for processing strong-motion earthquake accelerograms (Trifunac, 1971, 1972; Hudson et aL, 1971) has been tested by comparing displacement curves computed from the twice-integrated accelerograph recordings with displacement curves computed from displacement- meter measurements. The displacement meters have transducers with natural periods typically several seconds long. Agreement is found to be very

M. D. Trifunac; V. W. Lee

1974-01-01

159

A note on the noise amplitudes in some strong motion accelerographs  

Microsoft Academic Search

The amplitudes of digitization and processing noise in strong motion digital and analog accelerographs are discussed and compared with those for hand and automatic digitization. By finding the period bands for which the signal-to-noise ratio in recorded accelerograms is greater than one, the values for the pass-band cutoff periods for data processing are presented. The Empirical scalings for amplitudes in

A. Amini; M. D. Trifunac; R. L. Nigbor

1987-01-01

160

Shallow shear wave velocity and Q structures at the El Centro Strong Motion Accelerograph Array  

Microsoft Academic Search

At three sites in the U.S. Geological Survey El Centro Strong Motion Accelerograph Array (EO5, EO6, and EO7), we have used the dispersive and attenuative properties of artificially generated Rayleigh waves to infer the depth dependence of shear wave velocity (beta) and quality factor (Q) and a site dependent equivalent elastic source spectrum. This approach provides an inexpensive means for

Terrance G. Barker; Jeffry L. Stevens

1983-01-01

161

Analysis of strong-motion data from the New Hampshire earthquake of 18 January 1982  

Microsoft Academic Search

This report provides a permanent record and presents an analysis of the strong-motion data from the New Hampshire earthquake of 18 January 1982 which occurred at latitude 43.5 degrees N. longtitude 71.6 degrees W. Thirty-six accelerograms were recorded and digitized. The raw digitized accelerograms were processed by the US Geological Survey, Seismic Engineering Branch, to provide baseline correction and integrals

1983-01-01

162

Strong-motion earthquake accelerograms at Brawley, California: January 25, 1975  

Microsoft Academic Search

During the Brawley earthquake swarm of January, February, 1975, a single strong-motion accelerograph installed after the swarm began recorded 27 positively identified earthquakes in 14 hr, at hypocentral distances of approximately 5 km. Eight of these had magnitudes (M\\/sub L\\/) greater than or equal to 3.5, and several had M\\/sub L\\/ less than 2.5; the instrument independently triggered 18 times.

D. A. Johnson; T. C. Hanks

1976-01-01

163

Geotechnical investigations at strong-motion stations in the Imperial Valley, California  

Microsoft Academic Search

This study involved investigations at Imperial Valley, California accelerograph stations, and was done because of the unique strong-motion data set recorded during the magnitude 6.5 earthquake of October 15, 1979. The project included the following investigations: (1) electronic cone-penetrometer soundings at nine stations; (2) drilling, sampling, and logging of 22 borings to depths of from about 30 to 244 m;

Porcella

1984-01-01

164

Simulation of strong ground motion in northern Iran using the specific barrier model  

NASA Astrophysics Data System (ADS)

In this study, based upon the calibrated specific barrier model (SBM) against the latest available strong motion data, ground motion prediction equations for soil and rock sites in northern Iran are developed. The SBM may provide the most complete, simple and self-consistent description of the faulting process, which is applicable in both 'near-fault' and 'far-field' regions. Consequently, the SBM may provide consistent ground motion simulations over the entire necessary frequency range and for all distances of engineering interests. To determine source parameters in this study, we used 163 three-component records of 32 earthquakes with magnitude ranging from MW 4.9 to 7.4 in northern Iran. In the database, records with hypocentral distances less than 200 km are chosen and only earthquakes whose moment-magnitude estimates are available have been used. Furthermore, using the best available information, recording sites are classified into two main geologic categories: rock and soil. Because of the lack of site amplification information in the most regions of the world including Iran, we used the H/V ratio method for estimating the site amplification. Moreover, the Kappa factor that shows diminishing the high-frequency amplitude is determined. In this study, two data sets are considered for determining the source parameters (??G and ??L) and the H/V ratio and the Kappa factor. Only S-wave part of signals is used in each analysis. Regression analysis is performed using 'random effects' method that considers both interseismic (event-to-event) and coseismic (within-event) variabilities to effectively deal with the problem of weighting observations from different earthquakes. The residuals are controlled against available northern Iranian strong ground motion data to verify that the model predictions are unbiased and that there are no significant residual trends with magnitude and distance. At first, it is assumed that no sign of self-similarity breakdown is observed between the source radius and its seismic moment. After controlling the results, the modified SBM should be used as some deviations have been observed. To verify the robustness of the results, the number of observations is changed by removing various randomly selected data sets from the original database, which results in unchanged results of the model. Stochastic simulations are then implemented to predict peak ground motion and response spectra parameters. The stochastic SBM predictions are in relatively good agreement with other available attenuation relationships proposed for Iran, Europe and Middle East. It has been shown that the proposed SBM of this study provides unbiased ground motion estimates over the entire frequency range of most engineering applications. It provides a reliable and physically realistic, yet computationally efficient, way to model strong ground motions.

Soghrat, M. R.; Khaji, N.; Zafarani, H.

2012-02-01

165

Complexity of the Mw 6.3 2009 L'Aquila (central Italy) earthquake: 2. Broadband strong motion modeling  

E-print Network

26 February 2012; published 21 April 2012. [1] Near-fault strong-ground motions (0.1­10 Hz) recorded of records, azimuthal coverage and presence of near- fault recordings [Ameri et al., 2009a; Zambonelli et alComplexity of the Mw 6.3 2009 L'Aquila (central Italy) earthquake: 2. Broadband strong motion

Cerveny, Vlastislav

166

Slip history of the 2003 San Simeon earthquake constrained by combining 1Hz GPS, strong motion, and teleseismic data  

Microsoft Academic Search

The slip history of the 2003 San Simeon earthquake is constrained by combining strong motion and teleseismic data, along with GPS static offsets and 1-Hz GPS observations. Comparisons of a 1-Hz GPS time series and a co-located strong motion data are in very good agreement, demonstrating a new application of GPS. The inversion results for this event indicate that the

Chen Ji; Kristine M. Larson; Ying Tan; Kyuhong Choi

2004-01-01

167

HYBRID STRONG GROUND MOTION SIMULATION OF EARTHQUAKES ASSOCIATED WITH THE NORTH ANATOLIAN FAULT ZONE  

NASA Astrophysics Data System (ADS)

Simulation of strong ground motions of large earthquakes in regions of sparse seismic recordings is essential in terms of understanding the physics of the earthquake, seismic design of man-made structures, and disaster mitigation. North Anatolian Fault zone has had a westward-propagating series of great earthquakes starting with the 1939 Erzincan (Ms=8.0) earthquake. In this study, simulations of two most recent major earthquakes of this series which occurred in the Marmara region are presented. Hybrid stochastic finite fault modeling is used to simulate strong ground motions of 17 August 1999 Kocaeli (Mw=7.4) and 12 November 1999 Duzce (Mw=7.1) earthquakes. This model combines the stochastic finite fault model based on a dynamic corner frequency concept, introduced by Motazedian and Atkinson (2005), with the analytical model proposed by Mavroeidis and Papageorgiou (2003) which accounts for the impulsive behavior of near-fault ground motions. Accelerograms of the 1999 Marmara earthquakes are used to calibrate source parameters of stress drop and pulsing area as well as the analytical near-fault model parameters. Simulated acceleration time series, Fourier Amplitude spectra and response spectra at the stations are presented. Synthetic maps of peak ground acceleration and spectral acceleration are formed for both bedrock and soil sites and compared with the observed damage distribution during the earthquakes.

Ugurhan, B.; Askan, A.

2009-12-01

168

Seismic hazard analysis of Tianjin area based on strong ground motion prediction  

NASA Astrophysics Data System (ADS)

Taking Tianjin as an example, this paper proposed a methodology and process for evaluating near-fault strong ground motions from future earthquakes to mitigate earthquake damage for the metropolitan area and important engineering structures. The result of strong ground motion was predicted for Tianjin main faults by the hybrid method which mainly consists of 3D finite difference method and stochastic Green’s function. Simulation is performed for 3D structures of Tianjin region and characterized asperity models. The characterized asperity model describing source heterogeneity is introduced following the fault information from the project of Tianjin Active Faults and Seismic Hazard Assessment. We simulated the worst case that two earthquakes separately occur. The results indicate that the fault position, rupture process and the sedimentary deposits of the basin significantly affect amplification of the simulated ground motion. Our results also demonstrate the possibility of practical simulating wave propagation including basin induced surface waves in broad frequency-band, for seismic hazard analysis near the fault from future earthquakes in urbanized areas.

Zhao, Boming

2010-08-01

169

Dynamic geometrical effects on strong ground motion in a normal fault model  

SciTech Connect

We report results of measurement of particle motion in a foam-rubber model of normal faulting and compare the results with similar results for a strike-slip geometry. Standard computer modeling of strong ground motion from normal fault earthquakes has used dislocation theory, in which slip along the shallow part of the fault is prescribed by assuming particular time functions for fault slip. Unfortunately, in the case of normal faults, there are essentially no near-fault data from large earthquakes to constrain the modeling. In an extensional faulting regime the static normal and shear stresses along the fault must approach zero at the surface, and thus the upper few kilometers of the fault have inherently less stored strain energy than the maximum possible for strike-slip faults. In addition there are dynamic effects from geometry and drop in fault-normal stress which affect the fault motion. Physical models of faulting, such as foam-rubber modeling, are guaranteed to obey static and dynamic mechanical laws and thus can be used to gain insight into the physical processes involved. In this study we compare surface accelerations from normal fault and strike-slip geometries. The data show surface accelerations near the normal fault trace that are systematically lower, by an average factor of about 0.1, compared to the accelerations at the side sensors, which represent strike-slip motion. These results suggest that kinematic modeling of ground motion using classical dislocation techniques is inappropriate on the shallow part of the fault. The results of this study are qualitatively similar to those obtained for numerical models, such as a dynamic lattice model [{ital Shi} {ital et al.}, 1997] and a finite element model [{ital Oglesby} {ital et al.}, 1998], lending support to the probability that similar effects take place in the real Earth. {copyright} 1999 American Geophysical Union

Brune, J.N.; Anooshehpoor, A. [Seismological Laboratory, University of Nevada, Reno (United States)] [Seismological Laboratory, University of Nevada, Reno (United States)

1999-01-01

170

The Quake-Catcher Network: Improving Earthquake Strong Motion Observations Through Community Engagement  

NASA Astrophysics Data System (ADS)

The Quake-Catcher Network (QCN) involves the community in strong motion data collection by utilizing volunteer computing techniques and low-cost MEMS accelerometers. Volunteer computing provides a mechanism to expand strong-motion seismology with minimal infrastructure costs, while promoting community participation in science. Micro-Electro-Mechanical Systems (MEMS) triaxial accelerometers can be attached to a desktop computer via USB and are internal to many laptops. Preliminary shake table tests show the MEMS accelerometers can record high-quality seismic data with instrument response similar to research-grade strong-motion sensors. QCN began distributing sensors and software to K-12 schools and the general public in April 2008 and has grown to roughly 1500 stations worldwide. We also recently tested whether sensors could be quickly deployed as part of a Rapid Aftershock Mobilization Program (RAMP) following the 2010 M8.8 Maule, Chile earthquake. Volunteers are recruited through media reports, web-based sensor request forms, as well as social networking sites. Using data collected to date, we examine whether a distributed sensing network can provide valuable seismic data for earthquake detection and characterization while promoting community participation in earthquake science. We utilize client-side triggering algorithms to determine when significant ground shaking occurs and this metadata is sent to the main QCN server. On average, trigger metadata are received within 1-10 seconds from the observation of a trigger; the larger data latencies are correlated with greater server-station distances. When triggers are detected, we determine if the triggers correlate to others in the network using spatial and temporal clustering of incoming trigger information. If a minimum number of triggers are detected then a QCN-event is declared and an initial earthquake location and magnitude is estimated. Initial analysis suggests that the estimated locations and magnitudes are similar to those reported in regional and global catalogs. As the network expands, it will become increasingly important to provide volunteers access to the data they collect, both to encourage continued participation in the network and to improve community engagement in scientific discourse related to seismic hazard. In the future, we hope to provide access to both images and raw data from seismograms in formats accessible to the general public through existing seismic data archives (e.g. IRIS, SCSN) and/or through the QCN project website. While encouraging community participation in seismic data collection, we can extend the capabilities of existing seismic networks to rapidly detect and characterize strong motion events. In addition, the dense waveform observations may provide high-resolution ground shaking information to improve source imaging and seismic risk assessment.

Cochran, E. S.; Lawrence, J. F.; Christensen, C. M.; Chung, A. I.; Neighbors, C.; Saltzman, J.

2010-12-01

171

Bulletin of the Seismological Society of America, Vol. 95, No. 1, pp. 347353, February 2005, doi: 10.1785/0120040097 Experiment on an Onsite Early Warning Method for the Taiwan  

E-print Network

, and the related Fou- rier amplitude of the initial part of strong-motion signals. With this approach, 2003; Wu and Teng, 2002, 2004). The Taiwan EWS established by CWB (Fig. 1a) uses a real- time strong-motion of seconds of warning time for impending ground motions, allowing for mitigation measures in the short term

Wu, Yih-Min

172

Strong ground motions of the 2009 L'Aquila earthquake: modeling and scenario simulations  

NASA Astrophysics Data System (ADS)

On April 6, 2009 a Mw 6.3 earthquake struck the L'Aquila city, one of the largest urban centers in the Abruzzo region (Central Italy), causing a large number of casualties and damage in the town and surrounding villages. The earthquake has been recorded by several digital stations of the Italian Strong-Motion Network. The collected records represent a unique dataset in Italy in terms of number and quality of records, azimuthal coverage and presence of near-fault recordings. Soon after the earthquake the damage in the epicentral area was also assessed providing macroseismic intensity estimates, in MCS scale, for 314 localities (I ?5). Despite the moderate magnitude of the L'Aquila earthquake, the strong-motion and macroseismic data in the vicinity of the fault depict a large variability of the observed shaking and damage. In this study we present broadband (0.1 - 10 Hz) ground motion simulations of the 2009 L'Aquila earthquake to be used for engineering purposes in the region. We utilize Hybrid Integral-Composite (HIC, Gallovi? and Brokešová, 2007) approach based on a k-square kinematic rupture model, combining low-frequency coherent and high-frequency incoherent source radiation and providing omega-squared source spectral decay. We first model the recorded seismograms in order to calibrate source parameters and to assess the capabilities of the broadband simulation model. To this end, position and slip amount of the two main asperities, the largest asperity time delay and the rupture velocity distribution on the fault is constrained, based on the low-frequency slip inversion result. Synthetic Green's functions are calculated in a 1D-layered crustal model including 1D soil profiles to account for site-specific response (where available). The goodness-of-fit is evaluated in time (peak values and duration) and frequency domains (elastic and inelastic response spectra) and shows a remarkable agreement between observed and simulated data at most of the stations. The results show that not only the local site effects improve the modeling results, but also that the spatial broadband ground-motion variability is to large extent controlled by the rupture kinematics revealed by the low-frequency inversion. We simulate the ground motion at a grid of sites and compared the observed macroseismic intensity distribution with that obtained applying ground-motion to intensity conversion equations to the synthetic data. We find that the spectral ordinates at periods larger than 2s are well correlated with the macroseismic intensity pattern observed in the epicentral area. Finally, we compare the synthetic ground-motion parameters with estimates from several empirical ground motion prediction equations (GMPEs). The comparison highlights potential drawbacks in using GMPEs to validate simulated motions and/or when used for engineering purposes.

Gallovi?, F.; Ameri, G.; Pacor, F.

2012-04-01

173

Comparing action gestures and classifier verbs of motion: evidence from Australian Sign Language, Taiwan Sign Language, and nonsigners' gestures without speech.  

PubMed

Recent research into signed languages indicates that signs may share some properties with gesture, especially in the use of space in classifier constructions. A prediction of this proposal is that there will be similarities in the representation of motion events by sign-naive gesturers and by native signers of unrelated signed languages. This prediction is tested for deaf native signers of Australian Sign Language (Auslan), deaf signers of Taiwan Sign Language (TSL), and hearing nonsigners using the Verbs of Motion Production task from the Test Battery for American Sign Language (ASL) Morphology and Syntax. Results indicate that differences between the responses of nonsigners, Auslan signers, and TSL signers and the expected ASL responses are greatest with handshape units; movement and location units appear to be very similar. Although not definitive, these data are consistent with the claim that classifier constructions are blends of linguistic and gestural elements. PMID:15858072

Schembri, Adam; Jones, Caroline; Burnham, Denis

2005-01-01

174

The SCEC Broadband Platform: A Collaborative Open-Source Software Package for Strong Ground Motion Simulation and Validation  

NASA Astrophysics Data System (ADS)

The Southern California Earthquake Center (SCEC) Broadband Platform is a collaborative software development project involving SCEC researchers, graduate students, and the SCEC Community Modeling Environment. The SCEC Broadband Platform is open-source scientific software that can generate broadband (0-100Hz) ground motions for earthquakes, integrating complex scientific modules that implement rupture generation, low and high-frequency seismogram synthesis, non-linear site effects calculation, and visualization into a software system that supports easy on-demand computation of seismograms. The Broadband Platform operates in two primary modes: validation simulations and scenario simulations. In validation mode, the Broadband Platform runs earthquake rupture and wave propagation modeling software to calculate seismograms of a historical earthquake for which observed strong ground motion data is available. Also in validation mode, the Broadband Platform calculates a number of goodness of fit measurements that quantify how well the model-based broadband seismograms match the observed seismograms for a certain event. Based on these results, the Platform can be used to tune and validate different numerical modeling techniques. During the past year, we have modified the software to enable the addition of a large number of historical events, and we are now adding validation simulation inputs and observational data for 23 historical events covering the Eastern and Western United States, Japan, Taiwan, Turkey, and Italy. In scenario mode, the Broadband Platform can run simulations for hypothetical (scenario) earthquakes. In this mode, users input an earthquake description, a list of station names and locations, and a 1D velocity model for their region of interest, and the Broadband Platform software then calculates ground motions for the specified stations. By establishing an interface between scientific modules with a common set of input and output files, the Broadband Platform facilitates the addition of new scientific methods, which are written by earth scientists in a number of languages such as C, C++, Fortran, and Python. The Broadband Platform's modular design also supports the reuse of existing software modules as building blocks to create new scientific methods. Additionally, the Platform implements a wrapper around each scientific module, converting input and output files to and from the specific formats required (or produced) by individual scientific codes. Working in close collaboration with scientists and research engineers, the SCEC software development group continues to add new capabilities to the Broadband Platform and to release new versions as open-source scientific software distributions that can be compiled and run on many Linux computer systems. Our latest release includes the addition of 3 new simulation methods and several new data products, such as map and distance-based goodness of fit plots. Finally, as the number and complexity of scenarios simulated using the Broadband Platform increase, we have added batching utilities to substantially improve support for running large-scale simulations on computing clusters.

Silva, F.; Maechling, P. J.; Goulet, C.; Somerville, P.; Jordan, T. H.

2013-12-01

175

Strong ground motion modelling of causative fault for the 2002 Avaj earthquake, Iran  

NASA Astrophysics Data System (ADS)

The suitability of a very fast method for obtaining synthesizing accelerograms has been demonstrated for a hybrid simulation technique of source wavelet and acceleration envelope waveform for the 2002 Avaj earthquake. This method is based on the amplitude modeled white noise and envelope waveform. The estimation of peak acceleration from a preliminary simulated record is based on using modeling parameters of rupture plane instead of empirical relations for peak acceleration. Based on comparison between observed and simulated strong ground motion data, a fair agreement is observed between simulated and observed records up to distances 40 km for peak acceleration and duration. The most important feature of the recorded strong motion is decay up to a distance of 40 km which is due to direct upgoing shear waves. At distance of 50 to 60 km peak acceleration increase, which is due to postcritical reflection from velocity gradient in the lower crust. A flat trend is observed for peak acceleration at distance of 60 to 100 km. The simulation indicates that the rupture is started at depth of 8 km and propagated from northwest to southeast. The causative fault for the 2002 Avaj earthquake shows similar mechanism to the 1962 Buin-Zahra earthquake.

Hamzehloo, H.

2005-11-01

176

Geotechnical investigations at strong-motion stations in the Imperial Valley, California  

SciTech Connect

This study involved investigations at Imperial Valley, California accelerograph stations, and was done because of the unique strong-motion data set recorded during the magnitude 6.5 earthquake of October 15, 1979. The project included the following investigations: (1) electronic cone-penetrometer soundings at nine stations; (2) drilling, sampling, and logging of 22 borings to depths of from about 30 to 244 m; (3) downhole P- and S-wave velocity surveys at 22 stations; (4) high-amplitude resonant column tests of undisturbed samples from several stations; and (5) numerous gamma, S-P, and resistivity logs and caliper and temperature measurements at selected stations. This study is part of a program to compile geotechnical data at selected locations in various regions and to use these data to make detailed comparisons of the geologic and seismic characteristics that will provide a means for quantitatively estimating strong ground motion at a given site and facilitate the development of seismic zonation techniques applicable to other regions. 29 refs., 13 figs., 4 tabs.

Porcella, R.L.

1984-08-01

177

Preliminary analysis of strong-motion recordings from the 28 September 2004 Parkfield, California earthquake  

USGS Publications Warehouse

The Parkfield 2004 earthquake yielded the most extensive set of strong-motion data in the near-source region of a magnitude 6 earthquake yet obtained. The recordings of acceleration and volumetric strain provide an unprecedented document of the near-source seismic radiation for a moderate earthquake. The spatial density of the measurements alon g the fault zone and in the linear arrays perpendicular to the fault is expected to provide an exceptional opportunity to develop improved models of the rupture process. The closely spaced measurements should help infer the temporal and spatial distribution of the rupture process at much higher resolution than previously possible. Preliminary analyses of the peak a cceleration data presented herein shows that the motions vary significantly along the rupture zone, from 0.13 g to more than 2.5 g, with a map of the values showing that the larger values are concentrated in three areas. Particle motions at the near-fault stations are consistent with bilateral rupture. Fault-normal pulses similar to those observed in recent strike-slip earthquakes are apparent at several of the stations. The attenuation of peak ground acceleration with distance is more rapid than that indicated by some standard relationships but adequately fits others. Evidence for directivity in the peak acceleration data is not strong. Several stations very near, or over, the rupturing fault recorded relatively low accelerations. These recordings may provide a quantitative basis to understand observations of low near-fault shaking damage that has been reported in other large strike-slip earthquak.

Shakal, A.; Graizer, V.; Huang, M.; Borcherdt, R.; Haddadi, H.; Lin, K. -W.; Stephens, C.; Roffers, P.

2005-01-01

178

A Test of the Applicability of NGA Models to the Strong Ground-Motion Data in the Iranian Plateau  

Microsoft Academic Search

The Next Generation Attenuation (NGA) project has now published several new sets of empirical ground-motion prediction equations (GMPEs) for PGA, PGV, and response spectral ordinates. These models significantly advance the state-of-the-art empirical ground-motion modeling and account for many effects that have not been directly accounted for in the existing Iranian GMPEs. Assuming that the present strong-motion database in Iran is

S. Naserieh; G. Hadi

2010-01-01

179

Preliminary results of strong ground motion simulation for the Lushan earthquake of 20 April 2013, China  

NASA Astrophysics Data System (ADS)

The earthquake occurred in Lushan County on 20 April, 2013 caused heavy casualty and economic loss. In order to understand how the seismic energy propagates during this earthquake and how it causes the seismic hazard, we simulated the strong ground motions from a representative kinematic source model by Zhang et al. (Chin J Geophys 56(4):1408-1411, 2013) for this earthquake. To include the topographic effects, we used the curved grids finite difference method by Zhang and Chen (Geophys J Int 167(1):337-353, 2006), Zhang et al. (Geophys J Int 190(1):358-378, 2012) to implement the simulations. Our results indicated that the majority of seismic energy concentrated in the epicentral area and the vicinal Sichuan Basin, causing the XI and VII degree intensity. Due to the strong topographic effects of the mountain, the seismic intensity in the border area across the northeastern of Boxing County to the Lushan County also reached IX degree. Moreover, the strong influence of topography caused the amplifications of ground shaking at the mountain ridge, which is easy to cause landslides. These results are quite similar to those observed in the Wenchuan earthquake of 2008 occurred also in a strong topographic mountain area.

Zhu, Gengshang; Zhang, Zhenguo; Wen, Jian; Zhang, Wei; Chen, Xiaofei

2013-08-01

180

3D Modeling of Strong Ground Motion in the Pacific Northwest From Large Earthquakes in the Cascadia Subduction Zone  

Microsoft Academic Search

The Cascadia subduction zone in the Pacific Northwest, USA, generates Great (megathrust) earthquakes with a recurrence period of about 500 years, most recently the M~9 event on January 26, 1700. Since no earthquake of such magnitude has occurred in the Pacific Northwest since the deployment of strong ground motion instruments, a large uncertainty is associated with the ground motions expected

K. B. Olsen; A. Geisselmeyer; W. J. Stephenson; P. M. Mai

2007-01-01

181

Regional Characterization of the Crust in Metropolitan Areas for Prediction of Strong Ground Motion  

NASA Astrophysics Data System (ADS)

Introduction: After the 1995 Kobe earthquake, the Japanese government increased its focus and funding of earthquake hazards evaluation, studies of man-made structures integrity, and emergency response planning in the major urban centers. A new agency, the Ministry of Education, Science, Sports and Culture (MEXT) has started a five-year program titled as Special Project for Earthquake Disaster Mitigation in Urban Areas (abbreviated to Dai-dai-toku in Japanese) since 2002. The project includes four programs: I. Regional characterization of the crust in metropolitan areas for prediction of strong ground motion. II. Significant improvement of seismic performance of structure. III. Advanced disaster management system. IV. Investigation of earthquake disaster mitigation research results. We will present the results from the first program conducted in 2002 and 2003. Regional Characterization of the Crust in Metropolitan Areas for Prediction of Strong Ground Motion: A long-term goal is to produce map of reliable estimations of strong ground motion. This requires accurate determination of ground motion response, which includes a source process, an effect of propagation path, and near surface response. The new five-year project was aimed to characterize the "source" and "propagation path" in the Kanto (Tokyo) region and Kinki (Osaka) region. The 1923 Kanto Earthquake is one of the important targets to be addressed in the project. The proximity of the Pacific and Philippine Sea subducting plates requires study of the relationship between earthquakes and regional tectonics. This project focuses on identification and geometry of: 1) Source faults, 2) Subducting plates and mega-thrust faults, 3) Crustal structure, 4) Seismogenic zone, 5) Sedimentary basins, 6) 3D velocity properties We have conducted a series of seismic reflection and refraction experiment in the Kanto region. In 2002 we have completed to deploy seismic profiling lines in the Boso peninsula (112 km) and the Sagami bay area (75 km) to image the subducting Philippine Sea plate. On the Boso line we drilled a hole at a depth of 2000 m with core sampling and logging including VSP. A high sensitivity down hole seismometer will bee installed at the hole. In 2003, a 71-km-long reflection/refraction line covered the Tokyo bay area to characterize the source area of the 1923 Kanto quake. The southern part of the line ran through the Miura peninsula, which was covered by a 20 x 15 km array consisting of 51 3-component continuously recording seismographs to identify the asperities suggested by strong motion studies. We also cover the eastern boundary of the Kanto Mountains in this fall. Reconstruction of source fault and velocity models allow for more realistic 3D seimic wave simulations. All of this information will be synthesized and provided to communities involved in probabilistic hazards analysis, risk assessment and societal response.

Hirata, N.; Sato, H.; Koketsu, K.; Umeda, Y.; Iwata, T.; Kasahara, K.

2003-12-01

182

Source Rupture Process of the 2007 Noto Hanto Earthquake, Japan, Obtained from Strong Ground Motion and GPS Data  

Microsoft Academic Search

The 2007 Noto Hanto earthquake (MJMA 6.9) occurred near the west coast of the Noto peninsula, central Japan, on March 25, 2007. This is an inland crustal earthquake having oblique slip source mechanism. The strong ground motions from this event brought severe damages on wooden houses in and around near-source region (e.g., Wajima city and Anamizu town). Near-source strong motion

K. Asano; T. Iwata

2007-01-01

183

Site-dependent spectra from the 1999 Turkey earthquakes considering different sets of strong-motion data  

Microsoft Academic Search

In the last decade extensive strong-motion measurements were carried out by the reconnaissance team of the German TaskForce for Earthquakes. Aftershocks were recorded by a mesh of temporarily installed strong-motion recorders during the field surveys to Turkey in 1998 (Adana\\/Ceyhan), 1999 (Izmit\\/Kocaeli and Duezce\\/Bolu) and 2002 (Sultandagi\\/Afyon). Particularly the two missions in 1999 provided a unique and comprehensive database of

J. Schwarz; C. Ende; J. Habenberger; D. H. Lang

2003-01-01

184

Rupture Process of the M7.9 Denali Fault, Alaska, Earthquake Determined from Strong-Motion Recordings  

Microsoft Academic Search

We have analyzed and modeled strong-motion recordings available to date of the M7.9 Denali Fault earthquake of November 3, 2002. The data are from instruments at epicentral distances of 60-290 km operated by the USGS National Strong Motion Network, the Advanced National Seismic System, and the Geophysical Institute of the University of Alaska. We have identified and located three major

A. D. Frankel; N. N. Biswas; A. H. Martirosyan; U. Dutta; D. E. McNamara

2002-01-01

185

Site effects in Avcilar, West of Istanbul, Turkey, from strong- and weak-motion data  

USGS Publications Warehouse

Approximately 1000 people were killed in the collapse of buildings in Istanbul, Turkey, during the 17 August 1999 I??zmit earthquake, whose epicenter was roughly 90 km east of the city. Most of the fatalities and damage occurred in the suburb of Avcilar that is 20 km further west of the epicenter than the city proper. To investigate this pattern of damage, the U.S. Geological Survey, in cooperation with the Kandilli Observatory and Earthquake Research Institute (KOERI), deployed portable digital seismographs at seven free-field sites in western Istanbul, to record aftershocks during the period from 24 August to 2 September. The primary objective of this deployment was to study the site effects by comparing the aftershock ground motions recorded at sites inside and outside the damaged area, and to correlate site effects with the distribution of the damaged buildings. In addition to using weak-motion data, mainshock and aftershock acceleration records from the KOERI permanent strong-motion array were also used in estimating the site effects. Site effects were estimated using S waves from both types of records. For the weak-motion data set, 22 events were selected according to the criteria of signal-to-noise ratio (S/N ratio) and the number of stations recording the same event. The magnitudes of these events ranged from 3.0 to 5.2. The acceleration data set consisted of 12 events with magnitudes ranging from 4.3 to 5.8 and included two mainshock events. Results show that the amplifying frequency band is, in general, less than 4 Hz, and the physical properties of the geologic materials are capable of amplifying the motions by a factor of 5-10. In this frequency band, there is a good agreement among the spectral ratios obtained from the two mainshocks and their aftershocks. The damage pattern for the 17 August I??zmit earthquake is determined by several factors. However, our study suggests that the site effects in Avcilar played an important role in contributing to the damage.

Ozel, O.; Cranswick, E.; Meremonte, M.; Erdik, M.; Safak, E.

2002-01-01

186

NetQuakes - A new approach to urban strong-motion seismology  

NASA Astrophysics Data System (ADS)

There is a recognized need for more densely sampled strong ground motion recordings in urban areas to provide more accurate ShakeMaps for post-earthquake disaster assessment and to provide data for structural engineers to improve design standards. Ideally, the San Francisco Bay area would have a strong ground motion recorder every 1-2 km to adequately sample the region’s varied geology and built environment. This would require the addition of thousands of instruments to the existing network. There are several fiscal and logistical constraints that prevent us from doing this with traditional strong motion instrumentation and telemetry. In addition to the initial expense of instruments and their installation, there are the continuing costs of telemetry and maintenance. To address these issues, the USGS implemented the NetQuakes project to deploy small, relatively inexpensive seismographs for installation in 1-2 story homes and businesses that utilize the host’s existing Internet connection. The recorder has 18 bit resolution with ±3g internal tri-axial MEMS accelerometers. Data is continuously recorded at 200 sps into a 1-2 week ringbuffer. When triggered, a miniSEED file is sent to USGS servers via the Internet. Data can also be recovered from the ringbuffer by a remote request through the servers. Following a power failure, the instrument can run for 36 hours using its internal battery. All client-server interactions are initiated by the instrument, so it safely resides behind a host’s firewall. Instrument and battery replacement can be performed by hosts to reduce maintenance costs. A connection to the host’s LAN, and thence to the public Internet, can be made using WiFi to minimize cabling. Although timing via a cable to an external GPS antenna is possible, it is simpler to use the Network Time Protocol (NTP) to synchronize the internal clock. NTP achieves timing accuracy generally better than a sample interval. Since February, 2009, we have installed more than 60 NetQuakes instruments in the San Francisco Bay Area and have successfully integrated their data into the near real time data stream of the Northern California Seismic System.

Luetgert, J. H.; Evans, J. R.; Hamilton, J.; Hutt, C. R.; Jensen, E. G.; Oppenheimer, D. H.

2009-12-01

187

Strong Motion Networks - Rapid Response and Early Warning Applications in Istanbul  

NASA Astrophysics Data System (ADS)

In recent years several strong motion networks have been established in Istanbul with a preparation purpose for future probable earthquake. This study addresses the introduction of current seismic networks and presentation of some recent results recorded in these networks. Istanbul Earthquake Early Warning System Istanbul Earthquake Early Warning System has ten strong motion stations which were installed as close as possible to Marmara Sea main fault zone. Continuous on-line data from these stations via digital radio modem provide early warning for potentially disastrous earthquakes. Considering the complexity of fault rupture and the short fault distances involved, a simple and robust Early Warning algorithm, based on the exceedance of specified threshold time domain amplitude levels is implemented. The current algorithm compares the band-pass filtered accelerations and the cumulative absolute velocity (CAV) with specified threshold levels. Istanbul Earthquake Rapid Response System Istanbul Earthquake Rapid Response System has one hundred 18 bit-resolution strong motion accelerometers which were placed in quasi-free field locations (basement of small buildings) in the populated areas of the city, within an area of approximately 50x30km, to constitute a network that will enable early damage assessment and rapid response information after a damaging earthquake. Early response information is achieved through fast acquisition and analysis of processed data obtained from the network. The stations are routinely interrogated on regular basis by the main data center. After triggered by an earthquake, each station processes the streaming strong motion data to yield the spectral accelerations at specific periods and sends these parameters in the form of SMS messages at every 20s directly to the main data center through a designated GSM network and through a microwave system. A shake map and damage distribution map (using aggregate building inventories and fragility curves) will then be automatically generated using the algorithm developed for this purpose. Loss assessment studies are complemented by a large citywide digital database on the topography, geology, soil conditions, building, infrastructure and lifeline inventory. The shake and damage maps will be conveyed to the governor's and mayor's offices, fire, police and army headquarters within 3 minutes using radio modem and GPRS communication. Self Organizing Seismic Early Warning Information Network (SOSEWIN) in Atakoy District SOSEWIN sensors were developed by GFZ and Humbold University as part of SAFER project and EDIM project, and with cooperation of KOERI, the sensors were installed in Atakoy district of Istanbul city with Early Warning purpose. The main features of the SOSEWIN system are each sensing unit is comprised of low-cost components, undertakes its own seismological data processing, analysis and archiving, and its self-organizing capability with wireless mesh network communication. Seismic Network in Important Structures Some of the critical structures located in Istanbul city such as Fatih Sultan Mehmet Suspension Bridge which is connecting Asian and European sides of the city, Hagia Sophia Museum and Suleymaniye Mosque which are historical structures with an age of over 1000 years and 450 years respectively, and Isbank Tower which is one of the tallest structures in the city with a height of 181.2m are monitorized to observe their seismic behavior.

Zulfikar, C.; Alcik, H.; Ozel, O.; Erdik, M.

2009-04-01

188

Options for the Future of the US National Strong-Motion Program  

USGS Publications Warehouse

This report constitutes the requested 'Options Document'. This report considers three options. Option I assumes a constant level of financial support for Operating Expenses (OE) with not additional personnel support. Option II assumes a slight increase in OE support of $150K for FY 99 and beyond. Option III considers the role that a NSMP must play if the nation's urgent need to record the main earthquake at locations of significance for society is to be met. Two parts of Option III are considered. The first part of this option, termed Option III A, considers the role that strong-motion recording in and near man-made structures must play if a near-real time hazard initiative is to be implemented in the United States; The second part of Option III; termed Option III B, considers the scope of a NSMP needed to address society's needs to record the main earthquake in locations of significance for future public earthquake safety.

1997-01-01

189

Attenuation Tomography Based on Strong Motion Data: Case Study of Central Honshu Region, Japan  

NASA Astrophysics Data System (ADS)

Three-dimensional frequency dependent S-wave quality factor (Q?(f)) value for the central Honshu region of Japan has been determined in this paper using an algorithm based on inversion of strong motion data. The method of inversion for determination of three-dimensional attenuation coefficients is proposed by H ashida and S himazaki (J Phys Earth. 32, 299-316, 1984) and has been used and modified by J oshi (Curr Sci. 90, 581-585, 2006; Nat Hazards. 43, 129-146, 2007) and J oshi et al. (J. Seismol. 14, 247-272, 2010). Twenty-one earthquakes digitally recorded on strong motion stations of Kik-net network have been used in this work. The magnitude of these earthquake ranges from 3.1 to 4.2 and depth ranging from 5 to 20 km, respectively. The borehole data having high signal to noise ratio and minimum site effect is used in the present work. The attenuation structure is determined by dividing the entire area into twenty-five three-dimensional blocks of uniform thickness having different frequency-dependent shear wave quality factor. Shear wave quality factor values have been determined at frequencies of 2.5, 7.0 and 10 Hz from record in a rectangular grid defined by 35.4°N to 36.4°N and 137.2°E to 138.2°E. The obtained attenuation structure is compared with the available geological features in the region and comparison shows that the obtained structure is capable of resolving important tectonic features present in the area. The proposed attenuation structure is compared with the probabilistic seismic hazard map of the region and shows that it bears some remarkable similarity in the patterns seen in seismic hazard map.

Kumar, Parveen; Joshi, A.; Verma, O. P.

2013-12-01

190

Consistency of GPS and strong-motion records: case study of Mw9.0 Tohoku-Oki 2011 earthquake  

E-print Network

GPS and strong-motion sensors are broadly used for the monitoring of structural health and Earth surface motions, focusing on response of structures, earthquake characterization and rupture modeling. Most studies have shown differences between the two systems at very long periods (e.g. >100sec). The aim of this study is the assessment of the compatibility of GPS and strong-motion records by comparing the consistency in the frequency domain and by comparing their respective displacement waveforms for several frequency bands. For this purpose, GPS and strong-motion records of 23 collocated sites of the Mw9.0 Tohoku 2011 earthquake were used to show that the consistency between the two datasets depends on the frequency of the excitation, the direction of the excitation signal and the distance from the excitation source.

Psimoulis, P; Meindl, M; Rothacher, M

2014-01-01

191

Seismic Strong Motion Array Project (SSMAP) to Record Future Large Earthquakes in the Nicoya Peninsula area, Costa Rica  

Microsoft Academic Search

The seismic strong motion array project (SSMAP) for the Nicoya Peninsula in northwestern Costa Rica is composed of 10 13 sites including Geotech A900\\/A800 accelerographs (three-component), Ref-Teks (three- component velocity), and Kinemetric Episensors. The main objectives of the array are to: 1) record and locate strong subduction zone mainshocks [and foreshocks, \\

G. Simila; K. McNally; R. Quintero; J. Segura

2006-01-01

192

Seismic Strong Motion Array Project (SSMAP) to Record Future Large Earthquakes in the Nicoya Peninsula area, Costa Rica  

Microsoft Academic Search

The seismic strong motion array project (SSMAP) for the Nicoya Peninsula in northwestern Costa Rica is composed of 10 - 13 sites including Geotech A900\\/A800 accelerographs (three-component), Ref-Teks (three- component velocity), and Kinemetric Episensors. The main objectives of the array are to: 1) record and locate strong subduction zone mainshocks [and foreshocks, \\

G. Simila; E. Lafromboise; K. McNally; R. Quintereo; J. Segura

2007-01-01

193

Engineering Analysis of Strong-motion Data Recorded During German Task Force Missions To Turkey (1998-2000)  

Microsoft Academic Search

Obviously, structural damage caused by strong earthquakes can not only be attributed to defects in design or construction, but rather the widely discussed phenomenon of local site effects has to be considered as well. In the last decade extensive strong-motion measurements were carried out by the reconnaissance team of the German TaskForce for Earthquakes. Missions to Turkey in 1998 (Adana,

J. Schwarz; C. Ende; J. Habenberger; D. H. Lang; M. Raschke

2002-01-01

194

Azimuth-dependent amplification of weak and strong ground motions within a fault zone (Nocera Umbra, central Italy)  

NASA Astrophysics Data System (ADS)

During three moderate-magnitude earthquakes occurred in September-October 1997 in the central Apennines, Italy, accelerations larger than 0.5 g were recorded in the town of Nocera Umbra, 10 to 15 km N-NW of the epicenters. The accelerograph is sited in a fault zone, close to a N30°E tectonic contact. Six temporary seismological stations installed across the fault recorded 82 aftershocks occurred in two seismogenic zones: the Colfiorito-Sellano area, S-SE of the array, and the Gualdo Tadino area, to the north. The array data reveal large variations in terms of both peak ground motions and spectral amplitudes. Within the fault zone, amplifications show a strong dependence on the source azimuth. At the accelerograph site, the effects are particularly large for events from S-SE: peak ground motions are a factor of 14 larger than those of a reference site and conventional spectral ratios attain amplitudes as large as 50 at 7 Hz along the N30°E direction of motion, parallel to the strike of the fault. Nineteen strong motion accelerograms were then used to compare ground motion properties between weak and strong events up to M0 = 1.2 × 1025 dyn cm. A particle motion analysis shows that the directional effect is also present in the strongest motions, even though the amplification of peak ground motion decreases when M0 increases. Results from stochastic simulations indicate that such a behavior is not due to nonlinearity: applying the empirical weak motion transfer functions in a purely linear model the observed peak ground motions of the largest events are fit satisfactorily.

Cultrera, Giovanna; Rovelli, Antonio; Mele, Giuliana; Azzara, Riccardo; Caserta, Arrigo; Marra, Fabrizio

2003-03-01

195

Preliminary Model for Scaling of Fourier Spectra of Strong Ground Motion Recorded on Kamchatka  

NASA Astrophysics Data System (ADS)

To determine the average relationship among the Fourier spectrum of horizontal acceleration FSA(f), moment magnitude MW and hypocentral distance R for Kamchatka earthquakes, we analyzed 44 analog strong-motion records recorded here in 1969-1993. The records of acceleration and velocity meters were obtained at 11 rock to medium-ground sites from 36 earthquakes with M W = 4.5-7.8, at distances R = 30-250 km and depths 0-80 km. Amplitude spectra FSA(f) were calculated from digitized, baseline corrected records of 81 horizontal components, and then divided by instrumental transfer function. After smoothing the values were picked at a set of fixed frequencies. With the scarce amount of data at hand it was impossible to determine reliably the entire FSA(MW, R| f) average trend surface. Hence we first performed distance equalization with distance corrections calculated on a theoretical basis, and thus reduced the observed data to the reference distance of R0 = 100 km. The model of distance attenuation applied included point source decay terms (1/R plus attenuation specified by Q(f) = 250 f0.8) and finite source correction (using the formula for a disc-shaped incoherent source, its size depending on MW); its general applicability was later checked by analysis of residuals. After reduction we determined the FSA(MW, R0|f) vs. MW trends. To do this we employed a multiple regression procedure with ground type and station dummy variables. The MW dependence was assumed to consist of two linear branches intersecting at MW = 6.5. The result of multiple regression represents the first systematic description of spectral properties of destructive ground motion for Kamchatka earthquakes. The empirical FSA vs. MW trend flattens as frequency increases. This flattening persists even between 3 and 16 Hz, suggesting the decrease of source-related fmax with increasing magnitude.

Petukhin, A. G.; Gusev, A. A.; Guseva, E. M.; Gordeev, E. I.; Chebrov, V. N.

196

Predicting trench and plate motion from the dynamics of a strong slab  

Microsoft Academic Search

The motion of oceanic plates is commonly related to the subduction of cold and dense oceanic material into the mantle. These models predict plate velocities from subduction velocities but the trench motion is not directly included in the computation. Here, using a recent compilation of a global data set, we found that the motion of trenches (either advancing or retreating

Claudio Faccenna; Arnauld Heuret; Francesca Funiciello; Serge Lallemand; Thorsten W. Becker

2007-01-01

197

Seismic Hazard Mapping and Microzonation in the Sikkim Himalaya through GIS Integration of Site Effects and Strong Ground Motion Attributes  

Microsoft Academic Search

The seismic ground motion hazard is mapped in the Sikkim Himalaya with local and regional site conditions incorporated through geographic information system. A strong motion network in Sikkim comprising of 9 digital accelerographs recorded more than 100 events during 1998–2002, of which 41 events are selected with signal-to-noise ratio =3 for the estimation of site response (SR), peak ground acceleration

Sankar Kumar Nath

2004-01-01

198

Inversion of ground motion spectrafor site response at 150 stations of the Yokohama high-density strong motion seismograph network  

Microsoft Academic Search

The inversion procedure of Andrews (1986) is applied to separate the source and path effects, and site response from ground motion spectra from sixteen moderate earthquakes observed for direct S-waves by a dense array of 150 accelerographs in the city of Yokohama, Japan. We constrain the source effect to the omega 2 model consideringthe focal mechanisms of the earthquakes. The

K. Tsuda; K. Koketsu

2001-01-01

199

Bulletin of the Seismological Society of America, Vol. 95, No. 3, pp. 11811185, June 2005, doi: 10.1785/0120040193 Rapid Assessment of Damage Potential of Earthquakes in Taiwan  

E-print Network

. All the events were well recorded by the Taiwan Strong Motion Instrumentation Pro- gram (TSMIP, are used. We found that the peak initial-displacement amplitude (Pd) correlates well with the peak ground-motion displacement (PGD) and the peak ground-motion velocity (PGV) at the same site. When Pd 0.5 cm, the event

Wu, Yih-Min

200

A site effect study of the Adapazari basin, Turkey, from strong- and weak-motion data  

NASA Astrophysics Data System (ADS)

Approximately 4000 people were killed due to collapse of buildings in downtown Adapazari during the 1999 Izmit, Turkey earthquake (Mw = 7.4). The downtown is located on a deep sedimentary basin, so-called Adapazari basin. We study site effects of the Adapazari basin based on strong- and weak-motion data obtained by a temporary array observation deployed in and around the Adapazari basin after the earthquake. Four moderate-size aftershocks (M4.6-M5.8) are selected in our study. We evaluate the S-wave amplifications in the basin by using the traditional spectral ratio method. The spectral ratios show that the S waves are considerably amplified in the frequency range of 0.5 to about 5 Hz at the basin sites, but are apparently de-amplified at frequencies higher than about 10 Hz. We make a quantitative interpretation of the empirical amplifications based on the S-wave velocity structures at the stiff-soil reference site as well as at the basin sites; these structures were estimated by the microtremor array measurements. Through the interpretation, we confirm that the amplifications at low frequencies are attributed to the thick sedimentary layers in the Adapazari basin and that the apparent de-amplifications at high frequencies are partly due to the reference site response. In addition to the considerable S-wave amplifications, the basin site records show long-period (about 2 sec) later phases after the S-wave arrival; these later phases are basin-transduced surface waves that are originated from the source and transmitted into the basin. The predominant period of these waves apparently depends on the earthquake magnitude. We conclude that heavy damage in downtown Adapazari during the 1999 Izmit earthquake was caused not only by strongly amplified S-waves but also by long-period basin surface waves of long duration.

Oguz, Ozel; Sasatani, Tsutomu

201

Adjoint Inversion for Extended Earthquake Source Kinematics From Very Dense Strong Motion Data  

NASA Astrophysics Data System (ADS)

Addressing key open questions about earthquake dynamics requires a radical improvement of the robustness and resolution of seismic observations of large earthquakes. Proposals for a new generation of earthquake observation systems include the deployment of “community seismic networks” of low-cost accelerometers in urban areas and the extraction of strong ground motions from high-rate optical images of the Earth's surface recorded by a large space telescope in geostationary orbit. Both systems could deliver strong motion data with a spatial density orders of magnitude higher than current seismic networks. In particular, a “space seismometer” could sample the seismic wave field at a spatio-temporal resolution of 100 m, 1 Hz over areas several 100 km wide with an amplitude resolution of few cm/s in ground velocity. The amount of data to process would be immensely larger than what current extended source inversion algorithms can handle, which hampers the quantitative assessment of the cost-benefit trade-offs that can guide the practical design of the proposed earthquake observation systems. We report here on the development of a scalable source imaging technique based on iterative adjoint inversion and its application to the proof-of-concept of a space seismometer. We generated synthetic ground motions for M7 earthquake rupture scenarios based on dynamic rupture simulations on a vertical strike-slip fault embedded in an elastic half-space. A range of scenarios include increasing levels of complexity and interesting features such as supershear rupture speed. The resulting ground shaking is then processed accordingly to what would be captured by an optical satellite. Based on the resulting data, we perform source inversion by an adjoint/time-reversal method. The gradient of a cost function quantifying the waveform misfit between data and synthetics is efficiently obtained by applying the time-reversed ground velocity residuals as surface force sources, back-propagating onto the locked fault plane through a seismic wave simulation and recording the fault shear stress, which is the adjoint field of the fault slip-rate. Restricting the procedure to a single iteration is known as imaging. The source reconstructed by imaging reproduces the original forward model quite well in the shallow part of the fault. However, the deeper part of the earthquake source is not well reproduced, due to the lack of data on the side and bottom boundaries of our computational domain. To resolve this issue, we are implementing the complete iterative procedure and we will report on the convergence aspects of the adjoint iterations. Our current work is also directed towards addressing the lack of data on other boundaries of our domain and improving the source reconstruction by including teleseismic data for those boundaries and non-negativity constraints on the dominant slip-rate component.

Ampuero, J. P.; Somala, S.; Lapusta, N.

2010-12-01

202

Analysis of strong-motion data from the New Hampshire earthquake of 18 January 1982  

SciTech Connect

This report provides a permanent record and presents an analysis of the strong-motion data from the New Hampshire earthquake of 18 January 1982 which occurred at latitude 43.5 degrees N. longtitude 71.6 degrees W. Thirty-six accelerograms were recorded and digitized. The raw digitized accelerograms were processed by the US Geological Survey, Seismic Engineering Branch, to provide baseline correction and integrals are presented in tabular and graphic form. The integrated velocities and displacements are presented in graphic form. The attenuation curves of the three orthogonal components for peak acceleration, peak velocity, peak displacement, and velocity spectrum intensity on the crest, abutment, and downstream sites of the five US Army Corps of Engineers earth dams were plotted and compared. The transverse component shows the highest energy at the Franklin Falls Dam. However, its attenuation rate is faster than the vertical and longitudinal components. The transverse component of the accelerograph located on the right abutment of Franklin Falls Dam (8 km from the epicenter) recorded a maximum acceleration of 0.55 g's, which is the highest acceleration ever recorded in the eastern United States. The integrated maximum velocity is 5.59 cm/sec, which is very low in comparison with other earthquake records in the western United States or other earthquake regions. 8 references, 6 figures, 3 tables.

Chang, F.K.

1983-09-01

203

Shallow shear wave velocity and Q structures at the El Centro strong motion accelerograph array  

NASA Astrophysics Data System (ADS)

At three sites in the U.S. Geological Survey El Centro Strong Motion Accelerograph Array (EO5, EO6 and EO7), we have used the dispersive and attenuative properties of artificially generated Rayleigh waves to infer the depth dependence of shear wave velocity (?) and quality factor (Q) and a site dependent equivalent elastic source spectrum. This approach provides an inexpensive means for determining two important quantities (? and Q) required to estimate the response of sites to earthquakes. We find that the shear velocities and the gradients in shear velocities down to depths of 100 meters at station EO6 (in the wedge between the Imperial and Brawley faults) are nearly twice those at either station EO5 and EO7 (east and west, respectively, of the wedge). Also, the seismogram character, surface wave dispersion and shear wave velocity structure at stations EO5 and EO7 are similar to each other while they are different from EO6. These results show significant structural differences between the wedge beneath EO6 and surrounding areas. The anomalously high accelerations recorded at EO6 during the 1979 Imperial Valley earthquake may be related to these differences.

Barker, Terrance G.; Stevens, Jeffry L.

1983-09-01

204

An evaluation of the strong ground motion recorded during the May 1, 2003 Bingo??l Turkey, earthquake  

USGS Publications Warehouse

An important record of ground motion from a M6.4 earthquake occurring on May 1, 2003, at epicentral and fault distances of about 12 and 9km, respectively, was obtained at a station near the city of Bingo??l, Turkey. The maximum peak ground values of 0.55 g and 36 cm/s are among the largest ground-motion amplitudes recorded in Turkey. From simulations and comparisons with ground motions from other earthquakes of comparable magnitude, we conclude that the ground motion over a range of frequencies is unusually high. Site response may be responsible for the elevated ground motion, as suggested from analysis of numerous aftershock recordings from the same station. The mainshock motions have some interesting seismological features, including ramps between the P-and S-wave that are probably due to near- and intermediate-field elastic motions and strong polarisation oriented at about 39 degrees to the fault (and therefore not in the fault-normal direction). Simulations of motions from an extended rupture explain these features. The N10E component shows a high-amplitude spectral acceleration at a period of 0.15 seconds resulting in a site specific design spectrum that significantly overestimates the actual strength and displacement demands of the record. The pulse signal in the N10E component affects the inelastic spectral displacement and increases the inelastic displacement demand with respect to elastic demand for very long periods. ?? Imperial College Press.

Akkar, S.; Boore, D. M.; Gulkan, P.

2005-01-01

205

Survey of strong motion earthquake effects on thermal power plants in California with emphasis on piping systems. Volume 2, Appendices  

SciTech Connect

Volume 2 of the ``Survey of Strong Motion Earthquake Effects on Thermal Power Plants in California with Emphasis on Piping Systems`` contains Appendices which detail the detail design and seismic response of several power plants subjected to strong motion earthquakes. The particular plants considered include the Ormond Beach, Long Beach and Seal Beach, Burbank, El Centro, Glendale, Humboldt Bay, Kem Valley, Pasadena and Valley power plants. Included is a typical power plant piping specification and photographs of typical power plant piping specification and photographs of typical piping and support installations for the plants surveyed. Detailed piping support spacing data are also included.

Stevenson, J.D. [Stevenson and Associates, Cleveland, OH (United States)

1995-11-01

206

Strong ground motion synthesis along the Sanyi-Tungshih-Puli seismic zone using empirical Green`s functions  

SciTech Connect

We synthesize strong ground motion from a M=7.25 earthquake along the NW-trending Sanyi-Tungshih-Puli seismic zone. This trend extends from Houlong to Taichung and forms a nearly continuous 78 km long seismic zone identified by the occurrence of M<5 events. It extends from a shallow depth all the way down to about 40 km. The entire length of the fault, if activated at one time, can lead to an event comparable to that the 1995 Kobe earthquake. With the improved digital CWBSN data now provided routinely by CWBSN, it becomes possible to use these data as empirical Green`s functions to synthesize potential ground motion for future large earthquakes. We developed a suite of 100 rupture scenarios for the earthquake and computed the commensurate strong ground motion time histories. We synthesized strong ground motion with physics-based solutions of earthquake rupture and applied physical bounds on rupture parameters. the synthesized ground motions obtained for a fixed magnitude and identifying the hazard to a site from the statistical distribution of engineering parameters, we have introduced a probabilistic component to the deterministic hazard calculation, The time histories suggested for engineering design are the ones that most closely match either the average or one standard deviation absolute acceleration response values.

Hutchings, L.; Foxall, W.; Kasameyer, P. [Lawrence Livermore National Lab., CA (United States); Wu, F.T. [State Univ. of New York, Buffalo, NY (United States). Dept. of Geological Sciences; Rau, R.-J. [Academia Sinica, Taipei (Taiwan, Province of China). Inst. of Earth Sciences; Jarpe, S. [California Univ., Santa Barbara, CA (United States). Inst. for Crustal Studies

1997-01-01

207

Kinematic analysis of strong motion P and SV waves from the sterling event  

SciTech Connect

P and SV velocity waveforms from the Sterling explosion of December 3, 1966, are analyzed from a point of view often taken in earthquake source studies. The detonation occurred in the cavity excavated by the Salmon explosion within the Tatum salt dome, Mississippii, Velocity recordings taken from nearby borehole strong motion instruments show the occurrence of significant SV energy (Perret, 1968a, b). Kinematic source models are constructed by considering constraints afforded by the preshot cavity, condition of the surrounding material, and aspects of the P and SV waveforms such as wave polarity and duration. Waveforms for these models are computed and compared directly with the data. Modeling results suggest that the SV waves were radiated primarily by induced normal faulting occurring beneath the cavity rather than by an asymmetric pressure distribution based on the preshot cavity geometry. Secodary arrivals within the P waveforms and SV amplitudes suggest that these normal faults also had a component of tensional displacement which was probably due to forceable injection of material from the blast. A measurement for Q/sub ..beta../ of 35 is obtained for salt from the amplitude decay and pulse width changes observed for SV waves along a profile taken at shot level. This value for Q/sub ..beta../ is for the region away from the cracked area induced by the previous Salmon explosion and qualitatively explains the differing frequency content observed at the closest Sterling sensors between P and SV waves. The anomalous SV radiation has little to do with 'tectonic' stress release but is a result of the medium's geometry and anisotropy.

Langston, C.A.

1983-04-10

208

Kinematic analysis of strong motion P and SV waves from the Sterling Event  

NASA Astrophysics Data System (ADS)

P and SV velocity waveforms from the Sterling explosion of December 3, 1966, are analyzed from a point of view often taken in earthquake source studies. The detonation occurred in the cavity excavated by the Salmon explosion within the Tatum salt dome, Mississippi. Velocity recordings taken from nearby borehole strong motion instruments show the occurrence of significant SV energy (Perret, 1968a, b). Kinematic source models are constructed by considering constraints afforded by the preshot cavity, condition of the surrounding material, and aspects of the P and SV waveforms such as wave polarity and duration. Waveforms for these models are computed and compared directly with the data. Modeling results suggest that the SV waves were radiated primarily by induced normal faulting occurring beneath the cavity rather than by an asymmetric pressure distribution based on the preshot cavity geometry. Secondary arrivals within the P waveforms and SV amplitudes suggest that these normal faults also had a component of tensional displacement which was probably due to forceable injection of material from the blast. A measurement for Q? of 35 is obtained for salt from the amplitude decay arid pulse width changes observed for SV waves along a profile taken at shot level. This value for Q? is for the region away from the cracked area induced by the previous Salmon explosion and qualitatively explains the differing frequency content observed at the closest Sterling sensors between P and SV waves. The anomalous SV radiation has little to do with `tectonic' stress release but is a result of the medium's geometry and anisotropy.

Langston, Charles A.

1983-04-01

209

North Anna Nuclear Power Plant Strong Motion Records of the Mineral, Virginia Earthquake of August 23, 2011  

NASA Astrophysics Data System (ADS)

The MW 5.8 Mineral, Virginia earthquake was recorded at a relatively short epicentral distance of about 18 km at the North Anna Nuclear Power Plant (NPP) by the SMA-3 magnetic tape digital accelerographs installed inside the plant's containment at the foundation and deck levels. The North Anna NPP is operated by the Virginia Electric and Power Company (VEPCO) and has two pressurized water reactors (PWR) units that began operation in 1978 and 1980, respectively. Following the earthquake, both units were safely shutdown. The strong-motion records were processed to get velocity, displacement, Fourier and 5% damped response spectra. The basemat record demonstrated relatively high amplitudes of acceleration of 0.26 g and velocity of 13.8 cm/sec with a relatively short duration of strong motion of 2-3 sec. Recorded 5% damped Response Spectra exceed Design Basis Earthquake for the existing Units 1 and 2, while comprehensive plant inspections performed by VEPCO and U.S. Nuclear Regulatory Commission have concluded that the damage to the plant was minimal not affecting any structures and equipment significant to plant operation. This can be explained in part by short duration of the earthquake ground motion at the plant. The North Anna NPP did not have free-field strong motion instrumentation at the time of the earthquake. Since the containment is founded on rock there is a tendency to consider basemat record as an approximation of the free-field recording. However, comparisons of deck and basemat records demonstrate that the basemat recording is also affected by structural resonance frequencies higher than 3 Hz. Structural resonances in the frequency range of 3-4 Hz can at least partially explain significant exceedance of observed motions relative to ground motion calculated using ground motion prediction equations.cceleration, velocity and displacement at the North Anna NPP basemat level. Amplitudes of acceleration, velocity and displacement at basemat and deck levels

Graizer, V.

2012-12-01

210

Estimation of local magnitude of rockbursts using strong motion accelerograms in the mines of Kolar Gold Fields  

Microsoft Academic Search

Rockbursts are minor earthquakes induced due to mining operations. The seismic signals recorded using geophones in the near field are generally saturated and are not suitable for estimating the true magnitudes. The strong-motion accelerograms recorded due to rockbursts are therefore used to obtain the Wood-Anderson synthetic seismograms for getting accurate and reliable values of the local magnitudes. Using several typical

Chinnappa Srinivasan; Yesurathenam Ahnoch Willy; Iswar D. Gupta

2010-01-01

211

Design of a low-cost servo-actuated shaking table for simulating ground motions with strong vertical component  

NASA Astrophysics Data System (ADS)

This article proposes a new set of configurationsfor the construction of a low cost servo-actuatedshake table with a wide range simulation ability, especially regarding ground motions with strong vertical components up to 3.86g and 1.62m acceleration and stroke respectively. Designing decision and challenges faced during the process are also presented.

Tsolakis, Efstratios

2014-10-01

212

Theoretical design and field deployment of a dense strong motion instrument network for the Alpine Fault, South Island, New Zealand  

Microsoft Academic Search

A dense network of strong motion seismometers is being developed in order to investigate the complexities of the upper crustal rupture process and propagation of major seismogenic sources such as the Alpine Fault and strands of the Marlborough Fault System defining the South Island sector of the Australia-Pacific plate boundary zone. The proposed network is designed as a dense array

C. Francois; J. Berril; J. Pettinga

2003-01-01

213

Tracking the Articulated Motion of Two Strongly Interacting Hands I. Oikonomidis, N. Kyriazis, A.A. Argyros  

E-print Network

Tracking the Articulated Motion of Two Strongly Interacting Hands I. Oikonomidis, N. Kyriazis, A- servations to track the full articulation of two hands that in- teract with each-other in a complex represents all possible con- figurations of two hands, each represented as a kinematic structure with 26

Argyros, Antonis

214

Applicability of characterized source model to prediction of broad-band strong ground motion for scenario earthquakes  

Microsoft Academic Search

Most of the uncertainties in predicting strong ground motion is to model source heterogeneities of future earthquakes. An available method we propose for characterizing the heterogeneous slip distribution on the fault plane is based on the empirical source characterization derived from the slip models of the crustal earthquakes by Somerville et al. (1999). Areas of asperities having large slips are

k kamae; k irikura

2001-01-01

215

PEAK HORIZONTAL ACCELERATION AND VELOCITY FROM STRONG MOTION RECORDS INCLUDING RECORDS FROM THE 1979 IMPERIAL VALLEY, CALIFORNIA, EARTHQUAKE  

Microsoft Academic Search

We have taken advantage of the recent increase in strong-motion data at close distances to derive new attenuation relations for peak horizontal acceler- ation and velocity. This new analysis uses a magnitude-independent shape, based on geometrical spreading and anelastic attenuation, for the attenuation curve. An innovation in technique is introduced that decouples the determination of the distance dependence of the

WILLIAM B. JOYNER; DAVID M. BOORE

1981-01-01

216

Observing Structure and Motion in Molecules with Ultrafast Strong Field and Short Wavelength Laser Radiation  

SciTech Connect

The term "molecular movie" has come to describe efforts to track and record Angstrom-scale coherent atomic and electronic motion in a molecule. The relevant time scales for this range cover several orders of magnitude, from sub-femtosecond motion associated with electron-electron correlations, to 100-fs internal vibrations, to multi-picosecond motion associated with the dispersion and quantum revivals of molecular reorientation. Conventional methods of cinematography do not work well in this ultrafast and ultrasmall regime, but stroboscopic "pump and probe" techniques can reveal this motion with high fidelity. This talk will describe some of the methods and recent progress in exciting and controlling this motion, using both laboratory lasers and the SLAC Linac Coherent Light Source x-ray free electron laser, and will further try to relate the date to the goal of molecular movies.

Bucksbaum, Philip H.

2011-04-13

217

Strong Ground-Motion Prediction in Seismic Hazard Analysis: PEGASOS and Beyond  

NASA Astrophysics Data System (ADS)

The SSHAC Level 4 approach to probabilistic seismic hazard analysis (PSHA), which could be considered to define the state-of-the-art in PSHA using multiple expert opinions, has been fully applied only twice, firstly in the multi-year Yucca Mountain study and subsequently (2002-2004) in the PEGASOS project. The authors of this paper participated as ground-motion experts in this latter project, the objective of which was comprehensive seismic hazard analysis for four nuclear power plant sites in Switzerland, considering annual exceedance frequencies down to 1/10000000. Following SSHAC procedure, particular emphasis was put on capturing both the aleatory and epistemic uncertainties. As a consequence, ground motion prediction was performed by combining several empirical ground motion models within a logic tree framework with the weights on each logic tree branch expressing the personal degree-of-belief of each ground-motion expert. In the present paper, we critically review the current state of ground motion prediction methodology in PSHA in particular for regions of low seismicity. One of the toughest lessons from PEGASOS was that in systematically and rigorously applying the laws of uncertainty propagation to all of the required conversions and adjustments of ground motion models, a huge price has to be paid in an ever-growing aleatory variability. Once this path has been followed, these large sigma values will drive the hazard, particularly for low annual frequencies of exceedance. Therefore, from a post-PEGASOS perspective, the key issues in the context of ground-motion prediction for PSHA for the near future are to better understand the aleatory variability of ground motion and to develop suites of ground-motion prediction equations that employ the same parameter definitions. The latter is a global rather than a regional challenge which might be a desirable long-term goal for projects similar to the PEER NGA (Pacific Earthquake Engineering Research Center, Next Generation of Attenuation of Ground Motions) project.

Scherbaum, F.; Bommer, J. J.; Cotton, F.; Bungum, H.; Sabetta, F.

2005-12-01

218

Slip history of the 1995 Kobe, Japan, earthquake determined from strong motion, teleseismic, and geodetic data  

USGS Publications Warehouse

Near-source ground motions, teleseismic body waveforms, and geodetic displacements produced by the 1995 Kobe, Japan, earthquake have been used to determine the spatial and temporal dislocation pattern on the faulting surfaces. Analysis of the slip model indicates that the ground motions recorded within the severely damaged region of Kobe originated from the region of relatively low slip (about 1 m) deep beneath Kobe and not from the shallow, higher slip regions (about 3 m) beneath Aqaji Island. Although the slip was relatively low beneath Kobe, the combined effects of source rupture directivity, a short slip duration, and site amplification conspired to generate very damaging ground motions within the city.

Wald, D.J.

1996-01-01

219

ISET Journal of Earthquake Technology, Paper No. 471, Vol. 43, No. 3, September 2006, pp. 65-74 ESTIMATION OF NEAR-FAULT STRONG GROUND MOTIONS FOR  

E-print Network

-74 ESTIMATION OF NEAR-FAULT STRONG GROUND MOTIONS FOR KEY ENGINEERING STRUCTURES Guoxin Wang*, Hongnan LiISET Journal of Earthquake Technology, Paper No. 471, Vol. 43, No. 3, September 2006, pp. 65 of the recorded strong motions. The spectral differences between small and strong earthquakes are described

Gupta, Vinay Kumar

220

Acceleration and volumetric strain generated by the Parkfield 2004 earthquake on the GEOS strong-motion array near Parkfield, California  

USGS Publications Warehouse

An integrated array of 11 General Earthquake Observation System (GEOS) stations installed near Parkfield, CA provided on scale broad-band, wide-dynamic measurements of acceleration and volumetric strain of the Parkfield earthquake (M 6.0) of September 28, 2004. Three component measurements of acceleration were obtained at each of the stations. Measurements of collocated acceleration and volumetric strain were obtained at four of the stations. Measurements of velocity at most sites were on scale only for the initial P-wave arrival. When considered in the context of the extensive set of strong-motion recordings obtained on more than 40 analog stations by the California Strong-Motion Instrumentation Program (Shakal, et al., 2004 http://www.quake.ca.gov/cisn-edc) and those on the dense array of Spudich, et al, (1988), these recordings provide an unprecedented document of the nature of the near source strong motion generated by a M 6.0 earthquake. The data set reported herein provides the most extensive set of near field broad band wide dynamic range measurements of acceleration and volumetric strain for an earthquake as large as M 6 of which the authors are aware. As a result considerable interest has been expressed in these data. This report is intended to describe the data and facilitate its use to resolve a number of scientific and engineering questions concerning earthquake rupture processes and resultant near field motions and strains. This report provides a description of the array, its scientific objectives and the strong-motion recordings obtained of the main shock. The report provides copies of the uncorrected and corrected data. Copies of the inferred velocities, displacements, and Psuedo velocity response spectra are provided. Digital versions of these recordings are accessible with information available through the internet at several locations: the National Strong-Motion Program web site (http://agram.wr.usgs.gov/), the COSMOS Virtual Data Center Web site (http://www.cosmos-eq.org), and the CISN Engineering and Berkeley data centers (http://www.quake.ca.gov/cisn-edc). They are also accessible together with recordings on the GEOS Strong-motion Array near Parkfield, CA since its installation in 1987 through the USGS GEOS web site ( http://nsmp.wr.usgs.gov/GEOS).

Borcherdt, Rodger D.; Johnston, Malcolm J.S.; Dietel, Christopher; Glassmoyer, Gary; Myren, Doug; Stephens, Christopher

2004-01-01

221

Strong ground motion in Central Alaska resulting from the Denali Fault M7.9 earthquake of November 3, 2002  

NASA Astrophysics Data System (ADS)

The USGS Geologic Hazards Program has coordinated with numerous agencies operating in the state of Alaska to produce a map of strong ground shaking that resulted from the November 03, 2002 M7.9 earthquake on the Denali fault system (DFS). We collected strong motion amplitudes from a wide variety of sources distributed throughout the state: the National Strong Motion Program (NSMP), the Alaska tsunami warning center (ATWC), the Advanced National Seismic System (ANSS), the Alyeska Pipeline service Company, the Alaska Earthquake Information Centers (AEIC) M6.7 aftershock deployment, and the University of Alaska Geophysical Institute strong motion network in Anchorage. We observe peak ground accelerations on the order of 30%g at stations located within a few kilometers of the fault, 10%g 90km from the DFS in Fairbanks, and 1%g for stations in Anchorage, approximately 200km from the DFS. We will present ShakeMaps based on combining observations with empirical predictions elsewhere, estimated from the distance to the DFS rupture, as well as maps based on combining observations with predicted peak amplitudes from a teleseismically-based finite fault model (Ji et al., this session). The coordinated effort to bring ShakeMap to Alaska has also resulted in the installation of numerous strong ground shaking sensors in the urban areas of Alaska, as part of the ANSS, with the goal of rapid notification to emergency services in the event of a large earthquake that affects the urban population centers.

McNamara, D. E.; Wald, D. J.; Benz, H.

2002-12-01

222

Strong Motion Simulation of the Niigata-ken Chuetsu-oki Earthquake (2007), Japan  

NASA Astrophysics Data System (ADS)

On July 16th, 2007, the Niigata-ken Chuetsu-oki Earthquake (M6.8) occurred off Niigata Prefecture in Japan, claiming 68 casualties and more than 4,000 injured. The heavily damaged areas were Kariwa Village and Kashiwazaki City of Niigata Prefecture, and a fire broke out in an electrical transformer at the Kashiwazaki-Kariwa Nuclear Power Plant (KKNPP). Regarding this earthquake, the several source models have been proposed. Based on the dimensions of the proposed source models, we simulate strong motion in the epicentral area including the KKNPP site by using the fourth order 3-D finite-difference method with staggered-discontinuous-grids, that is, GMS code (Aoi.S and H. Fujiwara, 1999). First, we try to modify the 3-D subsurface structure model of Niigata Prefecture, developed and provided by JNES (Japan Nuclear Energy Safety Organization). To calibrate this model, we simulate three aftershocks recordings at KKNPP, assuming point sources with the source mechanisms provided by F-net. The shapes of the main portion of the velocity waveform are well reproduced in general. However, regarding the time differences between P-wave and S-wave (i.e., S-P time), the results do not show good match between observed data and calculations. In order to correct the difference in S-P time, we set a horizontal boundary at the depth of 12.5km in the bedrock and assigned different velocity structures for the shallow and deep part of the bedrock. As a result, we can match S-P time of the shallow aftershock. Next, we simulate the main shock recordings using the modified subsurface structure described above. Since the observed data of the main shock shows three distinctive velocity pulses, the initial model that we adopt consists of a three asperities source model from the previous study of Kawabe and Kamae (2008). The following is our calculation procedure. First, the shapes of slip velocity time functions are assumed to be a simple triangle. Then, simulated time histories are convolved with the shapes of the assumed slip velocity time function for each asperity. Finally, time histories of each asperity are overlapped considering the time delay between ruptures. As a result, by multiplying the seismic moment of two asperities (Asperity 1 and 3) by 1.5 and searching appropriate shapes of the slip velocity functions for three asperities, we can reproduce the observation recordings at KKNPP. However, large amplitude of the third velocity pulse in EW component cannot be reproduced. By plotting the particle motions of velocity time histories, we confirm that the third pulse with large amplitude at station KK1 appears in a different direction from the predominant direction seen in the calculated velocities. We will include the other observed sites to our targets and modify the shape of slip velocity time functions. We will also investigate the cause of conspicuous velocity pulse dominantly in the EW component, scrutinizing either from the local subsurface structure or the source process complexity.

Nitta, Y.; Matsushima, S.; Kawase, H.

2010-12-01

223

Modeling and simulation of near-fault strong ground motions for earthquake engineering applications  

Microsoft Academic Search

This dissertation aims at providing to earthquake engineers simple tools and techniques that enhance the physical understanding, characterization, proper parameterization, analytical modeling, and numerical simulation of near-fault ground motions for earthquake engineering applications. A simple analytical model is proposed for the representation of near-source ground motions that adequately describes the impulsive character of near-fault seismic excitations both qualitatively and quantitatively.

George P. Mavroeidis

2004-01-01

224

Field relations between the spectral composition of ground motion and hydrological effects during the 1999 Chi-Chi (Taiwan) earthquake  

Microsoft Academic Search

The possibility that the frequency content of ground motion in earthquakes affects hydrological responses to earthquakes has yet to be extensively tested in the field. The Mw = 7.6 Chi-Chi earthquake provided an opportunity to do so, as widespread liquefaction and groundwater level changes were recorded by instrumentation in the Choshui Alluvial Fan. Analysis of the resulting data shows that

Alexander Wong; Chi-Yuen Wang

2007-01-01

225

Estimation of local magnitude of rockbursts using strong motion accelerograms in the mines of Kolar Gold Fields  

NASA Astrophysics Data System (ADS)

Rockbursts are minor earthquakes induced due to mining operations. The seismic signals recorded using geophones in the near field are generally saturated and are not suitable for estimating the true magnitudes. The strong-motion accelerograms recorded due to rockbursts are therefore used to obtain the Wood-Anderson synthetic seismograms for getting accurate and reliable values of the local magnitudes. Using several typical strong-motion accelerograms of rockbursts in the mines of Kolar Gold Fields, the magnitudes have been computed in the present study. Correlations of peak ground acceleration and peak ground velocity with the magnitude, studied for the rockbursts vis-à-vis the natural earthquakes in the Koyna dam area, suggest the mechanical similarity between the two different types of events. The results and findings are described in this paper.

Srinivasan, Chinnappa; Willy, Yesurathenam Ahnoch; Gupta, Iswar D.

2010-04-01

226

STRONG MOTION DATA PROCESSING AND RECORDING AT UNIVERSITY OF SOUTHERN CALIFORNIA  

E-print Network

of the software developed by Trifunac and Lee [1,2]. Baseline correction is performed by high-pass filtering recorded accelerograms are also baseline corrected by high pass filtering, as random piecewise baseline motion accelerograms, (2) routine processing of large accelerogram data sets and database organization

Southern California, University of

227

TOPOGRAPHIC SITE RESPONSE AT A QUATERNARY TERRACE IN HACHIOJI, JAPAN, OBSERVED IN STRONG MOTIONS AND MICROTREMORS  

Microsoft Academic Search

SUMMARY We investigated a topographic site effect of a Quaternary terrace in Hachioji, Japan, on ground-motion amplification. The terrace discussed herein is about 12-m high consisting of volcanic ash, clay, silt and sand. 7 accelerographs were deployed in the site: 6 on the crest and 1 on the base of the terrace. The maximum PGA and PGV ratios with respect

Takumi TOSHINAWA; Yoshiaki Hisada; Katsuaki KONNO; Akihiro SHIBAYAMA; Yuya HONKAWA; Hiromichi ONO

228

Revelations from a single strong-motion record retreived during the 27 June 1998 Adana (Turkey) earthquake  

USGS Publications Warehouse

During the 27 June 1998 Adana (Turkey) earthquake, only one strong-motion record was retrieved in the region where the most damage occurred. This single record from the station in Ceyhan, approximately 15 km from the epicenter of that earthquake, exhibits characteristics that are related to the dominant frequencies of the ground and structures. The purpose of this paper is to explain the causes of the damage as inferred from both field observations and the characteristics of a single strong-motion record retrieved from the immediate epicentral area. In the town of Ceyhan there was considerable but selective damage to a significant number of mid-rise (7-12 stories high) buildings. The strong-motion record exhibits dominant frequencies that are typically similar for the mid-rise building structures. This is further supported by spectral ratios derived using Nakamura's method [QR of RTRI, 30 (1989) 25] that facilitates computation of a spectral ratio from a single tri-axial record as the ratio of amplitude spectrum of horizontal component to that of the vertical component [R = H(f)/V(f)]. The correlation between the damage and the characteristics exhibited from the single strong-motion record is remarkable. Although deficient construction practices played a significant role in the extent of damage to the mid-rise buildings, it is clear that site resonance also contributed to the detrimental fate of most of the mid-rise buildings. Therefore, even a single record can be useful to explain the effect of site resonance on building response and performance. Such information can be very useful for developing zonation criteria in similar alluvial valleys. Published by Elsevier Science Ltd.

Celebi, M.

2000-01-01

229

Estimation of local magnitude of rockbursts using strong motion accelerograms in the mines of Kolar Gold Fields  

Microsoft Academic Search

Rockbursts are minor earthquakes induced due to mining operations. The seismic signals recorded using geophones in the near\\u000a field are generally saturated and are not suitable for estimating the true magnitudes. The strong-motion accelerograms recorded\\u000a due to rockbursts are therefore used to obtain the Wood-Anderson synthetic seismograms for getting accurate and reliable values\\u000a of the local magnitudes. Using several typical

Chinnappa Srinivasan; Yesurathenam Ahnoch Willy; Iswar D. Gupta

2010-01-01

230

Comparison of strong-motion spectra with teleseismic spectra for three magnitude 8 subduction-zone earthquakes  

Microsoft Academic Search

A comparison of strong-motion spectra and teleseismic spectra was made for three Mw 7.8 to 8.0 earthquakes: the 1985 Michoacan (Mexico) earthquake, the 1985 Valparaiso (Chile) earthquake, and the 1983 Akita-Oki (Japan) earthquake. The decay of spectral amplitude with the distance from the station was determined, considering different measures of distance from a finite fault, and it was found to

Heidi Houston; Hiroo Kanamori

1990-01-01

231

Temporal changes in S-wave velocity structure at a borehole site after strong ground motion shock  

Microsoft Academic Search

We analyzed a pair of surface and downhole accelerographs at station SMNH01 of KiK-net, which experienced strong ground motion up to 844 gal by the 2000 Western Tottori Earthquake (06\\/10\\/2000, MW6.7), Japan, to examine how the shallow subsurface structure changes with time. Station SMNH01 has a borehole of 100 m depth, where sandy gravel distributes from 0 to 11 m

K. Sawazaki; H. Sato; H. Nakahara; T. Nishimura

2007-01-01

232

Short Note Site Effect of the Strong-Motion Site at Tolmezzo-Ambiesta Dam in Northeastern Italy  

Microsoft Academic Search

A spectral analysis of strong-motion data and ambient noise at the Tolmezzo-Ambiesta dam accelerograph (TLM1) site is performed to explain the high horizontal peak acceleration of 0.36g recorded during the Mw 6.4, 6 May 1976 Friuli (northeastern Italy) earthquake. The spectral response of the accelerographic site is estimated from the mainshocks and aftershocks of the 1976 seismic sequence by different

C. Barnaba; E. Priolo; A. Vuan; M. Romanelli

2007-01-01

233

Strong motion envelope modelling of the source of the Chamoli earthquake of March 28, 1999 in the Garhwal Himalaya, India  

Microsoft Academic Search

Garhwal Himalaya has been rocked by two major earthquakes in the span of just eight years, viz. Uttarkashi earthquake of 20th Oct, 1991 and Chamoli earthquake of 28th March, 1999. Chamoli earthquake of March 28, 1999 was recorded at 11 different stations of a strong motion array installed in the epicentral region. The maximum peak ground acceleration (353 cm\\/s2) was

A. Joshi

2001-01-01

234

3D simulation of near-fault strong ground motion: comparison between surface rupture fault and buried fault  

Microsoft Academic Search

In this paper, near-fault strong ground motions caused by a surface rupture fault (SRF) and a buried fault (BF) are numerically\\u000a simulated and compared by using a time-space-decoupled, explicit finite element method combined with a multi-transmitting\\u000a formula (MTF) of an artificial boundary. Prior to the comparison, verification of the explicit element method and the MTF\\u000a is conducted. The comparison results

Qifang Liu; Yifan Yuan; Xing Jin

2007-01-01

235

Kepler Motion  

NSDL National Science Digital Library

This website, from the National Taiwan Normal University, provides a demonstration of Kepler's laws of planetary motion. The site offers a description of all three laws and a brief history of Johann Kepler and his discoveries. The applet can be adjusted to display several different variables of planetary motion to simulate each law effectively.

Hwang, Fu-Kwun

2008-10-28

236

Attenuation and Directivity of Peak Ground Acceleration (PGA) in Near Fault Strong Motion from M6.0 Parkfield, California Earthquake  

Microsoft Academic Search

The Parkfield earthquake strong motion data set presents a rare opportunity to study a relatively large number of data recordings at stations near a fault. The earthquake was recorded by 46 strong motion stations located within 10 km from the fault with most of the data recorded by the film SMA-1 instruments. A comparison of the peak acceleration data for

V. Graizer; A. Shakal

2004-01-01

237

Exact equations of motion for natural orbitals of strongly driven two-electron systems  

E-print Network

Natural orbital theory is a computationally useful approach to the few and many-body quantum problem. While natural orbitals are known and applied since many years in electronic structure applications, their potential for time-dependent problems is being investigated only since recently. Correlated two-particle systems are of particular importance because the structure of the two-body reduced density matrix expanded in natural orbitals is known exactly in this case. However, in the time-dependent case the natural orbitals carry time-dependent phases that allow for certain time-dependent gauge transformations of the first kind. Different phase conventions will, in general, lead to different equations of motion for the natural orbitals. A particular phase choice allows us to derive the exact equations of motion for the natural orbitals of any (laser-) driven two-electron system explicitly, i.e., without any dependence on quantities that, in practice, require further approximations. For illustration, we solve th...

Rapp, J; Bauer, D

2014-01-01

238

Strong ground motion simulation during the November 1759 Earthquake along Serghaya Fault in the metropolitan of Damascus, Syria  

NASA Astrophysics Data System (ADS)

The seismic hazard potential for metropolitan of Damascus, Syria is mainly controlled by earthquakes along Serghaya Fault which is a branch of Dead Sea Fault System. In this study, strong ground motion due to the November 1759 Earthquake along the fault of Serghaya was estimated with a numerical simulation technique. In the simulation, the Kostrov-like slip-velocity function was used as an input to the discrete wave number method to simulate the strong ground motions in a broadband frequency range. In order to model the incoherent rupture propagation which can excite large high-frequency waves, random numbers are added to arrival time of circular rupture front. MMI intensities calculated from the synthetic ground motions are compared with the observed values by Ambraseys and Barazangi (J Geophys Res 94:4007-4013, 1989). The calculated intensities are in good agreement with the observed ones at the most sites that validate appropriateness of the proposed source model. The PGA and PGV in the eastern region of Damascus city are higher than those in the western region due to the effects of local site amplification. The simulated high-frequency (1.0-6.0 Hz) ground motions for the sites in the Damascus city are higher than the design requirements defined by the Syrian building code. Furthermore, the simulated high-frequency ground motions for sites in the focal region are bigger than the design requirements in the case of the near-fault factors and are not considered. That demonstrates the appropriateness of considering the near-fault factors for a site near the focal region as introduced by the new building code.

Zaineh, Hussam Eldein; Yamanaka, Hiroaki; Dhakal, Yadab Prasad; Dakkak, Rawaa; Daoud, Mohamad

2013-10-01

239

Strong Ground-Motion Prediction in Seismic Hazard Analysis: PEGASOS and Beyond  

Microsoft Academic Search

The SSHAC Level 4 approach to probabilistic seismic hazard analysis (PSHA), which could be considered to define the state-of-the-art in PSHA using multiple expert opinions, has been fully applied only twice, firstly in the multi-year Yucca Mountain study and subsequently (2002-2004) in the PEGASOS project. The authors of this paper participated as ground-motion experts in this latter project, the objective

F. Scherbaum; J. J. Bommer; F. Cotton; H. Bungum; F. Sabetta

2005-01-01

240

A Test of a Strong Ground Motion Prediction Methodology for the 7 September 1999, Mw=6.0 Athens Earthquake  

SciTech Connect

We test a methodology to predict the range of ground-motion hazard for a fixed magnitude earthquake along a specific fault or within a specific source volume, and we demonstrate how to incorporate this into probabilistic seismic hazard analyses (PSHA). We modeled ground motion with empirical Green's functions. We tested our methodology with the 7 September 1999, Mw=6.0 Athens earthquake, we: (1) developed constraints on rupture parameters based on prior knowledge of earthquake rupture processes and sources in the region; (2) generated impulsive point shear source empirical Green's functions by deconvolving out the source contribution of M < 4.0 aftershocks; (3) used aftershocks that occurred throughout the area and not necessarily along the fault to be modeled; (4) ran a sufficient number of scenario earthquakes to span the full variability of ground motion possible; (5) found that our distribution of synthesized ground motions span what actually occurred and their distribution is realistically narrow; (6) determined that one of our source models generates records that match observed time histories well; (7) found that certain combinations of rupture parameters produced ''extreme'' ground motions at some stations; (8) identified that the ''best fitting'' rupture models occurred in the vicinity of 38.05{sup o} N 23.60{sup o} W with center of rupture near 12 km, and near unilateral rupture towards the areas of high damage, and this is consistent with independent investigations; and (9) synthesized strong motion records in high damage areas for which records from the earthquake were not recorded. We then developed a demonstration PSHA for a source region near Athens utilizing synthesized ground motion rather that traditional attenuation. We synthesized 500 earthquakes distributed throughout the source zone likely to have Mw=6.0 earthquakes near Athens. We assumed an average return period of 1000 years for this magnitude earthquake in the particular source zone, thereby having simulated a catalog of ground motion for a period of 500,000 years. The distribution of traditional ground motion parameters of peak acceleration or spectral ordinates then becomes the synthesized record from which we develop hazard curves in the form of the annual probability of exceedance. This approach replaces the aleatory uncertainty that current PSHA studies estimate by regression of empirical parameters from the worldwide database with epistemic uncertainty on what specific sources actually do at specific sites. This is a fundamental change for PSHA and eliminates the need to extrapolate current empirical data that was gathered over about 50 years to represent values for 10{sup -3} annual probability of exceedance or less. This difference becomes especially significant for very sensitive structures that require estimates for 10{sup -5} or less exceedance.

Hutchings, L; Ioannidou, E; Voulgaris, N; Kalogeras, I; Savy, J; Foxall, W; Stavrakakis, G

2004-08-06

241

Structure and dynamics of an imidazoline nitroxide side chain with strongly hindered internal motion in proteins  

NASA Astrophysics Data System (ADS)

A disulfide-linked imidazoline nitroxide side chain (V1) has a similar and highly constrained internal motion at diverse topological sites in a protein, unlike that for the disulfide-linked pyrroline nitroxide side chain (R1) widely used in site directed spin labeling EPR. Crystal structures of V1 at two positions in a helix of T4 Lysozyme and quantum mechanical calculations suggest the source of the constraints as intra-side chain interactions of the disulfide sulfur atoms with both the protein backbone and the 3-nitrogen in the imidazoline ring. These interactions apparently limit the conformation of the side chain to one of only three possible rotamers, two of which are observed in the crystal structure. An inter-spin distance measurement in frozen solution using double electron-electron resonance (DEER) gives a value essentially identical to that determined from the crystal structure of the protein containing two copies of V1, indicating that lattice forces do not dictate the rotamers observed. Collectively, the results suggest the possibility of predetermining a unique rotamer of V1 in helical structures. In general, the reduced rotameric space of V1 compared to R1 should simplify interpretation of inter-spin distance information in terms of protein structure, while the highly constrained internal motion is expected to extend the dynamic range for characterizing large amplitude nanosecond backbone fluctuations.

Toledo Warshaviak, Dora; Khramtsov, Valery V.; Cascio, Duilio; Altenbach, Christian; Hubbell, Wayne L.

2013-07-01

242

Evaluation model of landslide hazards induced by the 2008 Wenchuan earthquake using strong motion data  

NASA Astrophysics Data System (ADS)

Landslides induced by the 2008 Wenchuan earthquake in the Longmenshan area were relatively well instrumented, which makes it possible to investigate the landslides using ground motion records. Firstly, this paper analyzes the data from Wenchuan earthquake on both regional and local site scale. The analyses show that the Newmark accumulative displacement calculated from the ground motion recorded in a particular geological hazard zone corresponds to the hazard intensity in that zone; the larger the displacement, the more serious the geologic hazard. The calculated result also shows that the displacement is related to the Arias intensity, which represents the total energy released during the earthquake at the observation site. Secondly, this paper constructs an evaluation model of Newmark displacement calculated with Arias intensities to estimate the subsequent slope failure resulting from the earthquake. The calculated results based on the model fit well with the distribution of actual landslides, suggesting that this method is useful for hazard evaluation. Therefore, this type of model can be used for estimating regional-scale distribution of earthquake-induced landslides and their associated hazards immediately after an earthquake.

Wang, Xiuying; Nie, Gaozhong; Ma, Mujun

2011-06-01

243

Structure and dynamics of an imidazoline nitroxide side chain with strongly hindered internal motion in proteins  

PubMed Central

A disulfide-linked imidazoline nitroxide side chain (V1) has a similar and highly constrained internal motion at diverse topological sites in a protein, unlike that for the disulfide-linked pyrroline nitroxide side chain (R1) widely used in site directed spin labeling EPR. Crystal structures of V1 at two positions in a helix of T4 Lysozyme and quantum mechanical calculations suggest the source of the constraints as intra-side chain interactions of the disulfide sulfur atoms with both the protein backbone and the 3-nitrogen in the imidazoline ring. These interactions apparently limit the conformation of the side chain to one of only three possible rotamers, two of which are observed in the crystal structure. An inter-spin distance measurement in frozen solution using double electron-electron resonance (DEER) gives a value essentially identical to that determined from the crystal structure of the protein containing two copies of V1, indicating that lattice forces do not dictate the rotamers observed. Collectively, the results suggest the possibility of predetermining a unique rotamer of V1 in helical structures. In general, the reduced rotameric space of V1 compared to R1 should simplify interpretation of interspin distance information in terms of protein structure, while the highly constrained internal motion is expected to extend the dynamic range for characterizing large amplitude nanosecond backbone fluctuations. PMID:23694751

Warshaviak, Dora Toledo; Khramtzov, Valery V.; Cascio, Duilio; Altenbach, Christian; Hubbell, Wayne L.

2013-01-01

244

Displaced rocks, strong motion, and the mechanics of shallow faulting associated with the 1999 Hector Mine, California, earthquake  

USGS Publications Warehouse

The paucity of strong-motion stations near the 1999 Hector Mine earthquake makes it impossible to make instrumental studies of key questions about near-fault strong-motion patterns associated with this event. However, observations of displaced rocks allow a qualitative investigation of these problems. By observing the slope of the desert surface and the frictional coefficient between these rocks and the desert surface, we estimate the minimum horizontal acceleration needed to displace the rocks. Combining this information with observations of how many rocks were displaced in different areas near the fault, we infer the level of shaking. Given current empirical shaking attenuation relationships, the number of rocks that moved is slightly lower than expected; this implies that slightly lower than expected shaking occurred during the Hector Mine earthquake. Perhaps more importantly, stretches of the fault with 4 m of total displacement at the surface displaced few nearby rocks on 15?? slopes, suggesting that the horizontal accelerations were below 0.2g within meters of the fault scarp. This low level of shaking suggests that the shallow parts of this rupture did not produce strong accelerations. Finally, we did not observe an increased incidence of displaced rocks along the fault zone itself. This suggests that, despite observations of fault-zone-trapped waves generated by aftershocks of the Hector Mine earthquake, such waves were not an important factor in controlling peak ground acceleration during the mainshock.

Michael, A. J.; Ross, S. L.; Stenner, H. D.

2002-01-01

245

Strong Erosion-Driven Nongravitational Effects in Orbital Motions of the Kreutz Sungrazing System's Dwarf Comets  

E-print Network

We investigate the relationship among the angular orbital elements --- the longitude of the ascending node, Omega, the inclination, i, and the argument of perihelion, omega --- of dwarf sungrazing comets of the Kreutz system, whose catalogued orbits were derived using a parabolic gravitational approximation. While in a plot of omega against Omega the major and dwarf sungrazers follow a similar law, in a plot of i against Omega they behave differently. The major sungrazers fit a curve of invariable (reference) apsidal orientation, whereas the dwarf comets lie along a curve that makes with it 15 deg. While the perihelion longitude of dwarf sungrazers is statistically constant, the perihelion latitude increases systematically with Omega. A perturbation analysis indicates that this is due to an acceleration normal to the orbit plane. The culprit is neglect of an erosion-driven acceleration in the motions of the dwarf sungrazers, as illustrated by computing, for several test SOHO/STEREO sungrazers, orbital solutio...

Sekanina, Zdenek

2014-01-01

246

Experimental investigation of strong ground motion due to thrust fault earthquakes  

NASA Astrophysics Data System (ADS)

Thrust fault earthquakes are studied in a laboratory earthquake setup previously used to investigate analog strike-slip seismic events. Dynamic mode II ruptures are generated along preexisting faults in an analog material, Homalite H-100, and their interaction with the free surface is studied for both sub-Rayleigh and supershear rupture speeds. High-speed digital photography and laser velocimeter diagnostics are used synergistically to identify and study the ground velocity signatures caused by the various features of the generated ruptures. The obtained surface-normal motions of both sub-Rayleigh and supershear ruptures show substantial asymmetry between the hanging and footwall, with the hanging wall experiencing much larger velocity amplitudes. The main features of the surface velocity traces at various stations can be explained by the calculated arrivals of various waves and fronts—Mach cones, Pand S waves, and sub-Rayleigh features. In both the sub-Rayleigh and supershear cases, the arrival of the rupture tip generates a prominent Rayleigh wave traveling along the simulated Earth's surface. Supershear events feature larger amplitudes of ground shaking profiles. All signatures in the surface motion records attenuate and broaden with increasing distance from the fault trace. The signatures corresponding to the arrival of the Mach fronts attenuate with distance at a slower rate than those from sub-Rayleigh ruptures. The arrival of the updip supershear rupture at the free surface creates a downdip propagating slip feature with its own Mach cone. These additional Mach fronts further amplify ground shaking on the hanging and footwalls.

Gabuchian, Vahe; Rosakis, Ares J.; Lapusta, Nadia; Oglesby, David D.

2014-02-01

247

Strong correlation of atomic thermal motion in the first coordination shell of a Cu-Zr metallic glass  

SciTech Connect

We demonstrate a strong correlation of atomic thermal motions in the first coordination shell of Cu{sub 50}Zr{sub 50} metallic glass using molecular dynamics simulations, which explains directly the small thermal expansion coefficient calculated by the first maxima of pair correlation functions. The vibrational anisotropy in the glass is found to be even higher than in crystalline copper. The parallel-perpendicular anisotropy gradually decreases upon heating. The anisotropy in Zr-Zr is the strongest bonds among all the interatomic bonds, which is also very stable near the glass transition at 700 K. Structurally, the anisotropy can be correlated to Cu-centered (0 2 8 1) clusters.

Zhang, Y.; Mattern, N. [IFW Dresden, Institut fuer Komplexe Materialien, Helmholtzstrasse 20, D-01069 Dresden (Germany)] [IFW Dresden, Institut fuer Komplexe Materialien, Helmholtzstrasse 20, D-01069 Dresden (Germany); Eckert, J. [IFW Dresden, Institut fuer Komplexe Materialien, Helmholtzstrasse 20, D-01069 Dresden (Germany) [IFW Dresden, Institut fuer Komplexe Materialien, Helmholtzstrasse 20, D-01069 Dresden (Germany); Institut fuer Werkstoffwissenschaft, Technische Universitaet Dresden, D-01062 Dresden (Germany)

2013-02-25

248

Strong motion characteristics of the 2011 Tohoku-Oki earthquake observed by K-NET and KiK-net  

NASA Astrophysics Data System (ADS)

The Tohoku-Oki earthquake was the largest earthquake occurred in and around Japan since the recorded history. This magnitude 9.0 megathrust earthquake initiated approximately 100 km off-shore Miyagi prefecture and the rupture extended 400 - 500 km along the subducting Pacific plate. Due to the large ground motions and tsunami associated by this event, more than twenty thousands people were killed or missing and more than 220 thousands houses and buildings were totally or partially destroyed. The Tohoku-Oki earthquake was the first M9-class earthquake that is closely recorded by a dense seismograph network. In this paper, we summarize the characteristics of the strong motions and the source process revealed by those data. The ground motions were recorded at more than 1200 K-NET and KiK-net stations. The peak ground accelerations (PGA) exceeded 1g at 20 sites and the largest PGA, 2933 gals, was observed at the K-NET Tsukidate station (MYG004). We estimated the precise spatial distribution of seismic intensity from the observed data considering the near-surface amplification, and found that roughly twenty million people were exposed to a shaking larger than JMA seismic intensity 5+ (>MMI 7). Huge numbers of large aftershocks and triggered earthquakes including M7-class crustal and intraslab earthquakes have been recorded. Those earthquakes occurred not only in the source area but also several hundreds kilometers away. Some of them were located much nearer to the populated urban areas than the main shock and human fatalities as well as severe building damages were caused by large ground shakings. The observed waveforms from the main shock are very complex; depending on the region, accelerograms show one to three conspicuous and long-duration phases as well as several phases with smaller amplitudes and shorter durations. A paste-up of accelerograms in Iwate, Miyagi and Fukushima prefectures ordered by latitude from north displays an initial strong seismic phase first observed at Miyagi stations and then propagating towards the north and south. A subsequent phase uniformly delayed by approximately 40 s is also clearly observed in the paste-up. In the southern region, Ibaraki and Chiba prefectures, only one distinct phase is observed. Fault rupture process inverted by a multi-time window analysis using the strong-motion waveforms is characterized by one large slip area with maximum slip of 48 m which extends from the area near the hypocenter toward the shallow part of the fault plane, far off the coast of Iwate, Miyagi and Fukushima prefectures (Suzuki et al., 2011, AGU fall meeting). Though the distribution of the total slip is simple, the feature of the rupture progression is very complicated. The duration and the timing of the slip have a large spatial variety within the fault. The fault slip near the coast off Miyagi prefecture, which is small compared to the peak fault slip, had a large contribution to the observed strong motions in Miyagi and Iwate prefectures. The complicated relationship between the rupture model derived using long period strong motions and the features of the observed acceleration waveforms suggests a frequency dependency of the seismic wave radiation and source process.

Aoi, S.; Kunugi, T.; Suzuki, W.; Morikawa, N.; Nakamura, H.; Pulido Hernandez, N. E.; Fujiwara, H.

2011-12-01

249

Running On-Demand Strong Ground Motion Simulations with the Second-Generation Broadband Platform  

NASA Astrophysics Data System (ADS)

We have developed the second-generation Southern California Earthquake Center (SCEC) Broadband Platform by integrating scientific modeling codes into a system capable of computing broadband seismograms (0-10 Hz) for historical and scenario earthquakes in California. The SCEC Broadband Platform is a collaborative software development project involving SCEC researchers, graduate students, and the SCEC Community Modeling Environment (SCEC/CME) software development group. SCEC scientific groups have contributed software modules to the Broadband Platform including rupture generation, low-frequency deterministic seismogram synthesis, high-frequency stochastic seismogram synthesis, and non-linear site effects. These complex scientific codes have been integrated into a system that supports easy on-demand computation of broadband seismograms. The SCEC Broadband Platform is designed to be used by both scientific and engineering researchers familiar with ground motion simulations. Users may calculate broadband seismograms for both historical earthquakes (validation events including Northridge, Loma Prieta, and Landers) and user-defined earthquakes. Users may select among various codebases for rupture generation, low-frequency synthesis, high-frequency synthesis, and incorporation of site effects, with the option of running a goodness-of-fit comparison against observed or simulated seismograms. The platform produces a variety of data products, including broadband seismograms, rupture visualizations, and goodness-of-fit plots. The Broadband Platform was implemented using software development best practices that support software accuracy, reliability, and ease of use, including version control, user documentation, acceptance tests, and formal software releases. Users can install the platform on their own machine, verify that it is installed correctly, and run their own simulations on demand. The Broadband Platform enables users to run complex ground motion modeling codes without detailed knowledge about how the codes are implemented. Users may run a validation event, supply their own simple source description, or provide a rupture description in Standard Rupture Format (SRF). Users may specify their own list of stations or use a provided list. Currently the platform supports stations and events in Southern California, the Bay Area, and the Mojave. In our poster, we will discuss the scientific capabilities of the Broadband Platform. We will describe the software engineering behind the platform development and the rigorous release procedure involved. Additionally, we will present simulations performed using the platform, including goodness-of-fit results, and discuss potential applications of on-demand broadband seismogram computation.

Callaghan, S.; Maechling, P. J.; Graves, R. W.; Somerville, P. G.; Collins, N.; Olsen, K. B.; Imperatori, W.; Jones, M.; Archuleta, R. J.; Schmedes, J.; Jordan, T. H.; Broadband Platform Working Group

2010-12-01

250

Seismic Strong Motion Array Project (SSMAP) to Record Future Large Earthquakes in the Nicoya Peninsula area, Costa Rica  

NASA Astrophysics Data System (ADS)

The seismic strong motion array project (SSMAP) for the Nicoya Peninsula in northwestern Costa Rica is composed of 10 - 13 sites including Geotech A900/A800 accelerographs (three-component), Ref-Teks (three- component velocity), and Kinemetric Episensors. The main objectives of the array are to: 1) record and locate strong subduction zone mainshocks [and foreshocks, "early aftershocks", and preshocks] in Nicoya Peninsula, at the entrance of the Nicoya Gulf, and in the Papagayo Gulf regions of Costa Rica, and 2) record and locate any moderate to strong upper plate earthquakes triggered by a large subduction zone earthquake in the above regions. Our digital accelerograph array has been deployed as part of our ongoing research on large earthquakes in conjunction with the Earthquake and Volcano Observatory (OVSICORI) at the Universidad Nacional in Costa Rica. The country wide seismographic network has been operating continuously since the 1980's, with the first earthquake bulletin published more than 20 years ago, in 1984. The recording of seismicity and strong motion data for large earthquakes along the Middle America Trench (MAT) has been a major research project priority over these years, and this network spans nearly half the time of a "repeat cycle" (~ 50 years) for large (Ms ~ 7.5- 7.7) earthquakes beneath the Nicoya Peninsula, with the last event in 1950. Our long time co- collaborators include the seismology group OVSICORI, with coordination for this project by Dr. Ronnie Quintero and Mr. Juan Segura. The major goal of our project is to contribute unique scientific information pertaining to a large subduction zone earthquake and its related seismic activity when the next large earthquake occurs in Nicoya. We are now collecting a database of strong motion records for moderate sized events to document this last stage prior to the next large earthquake. A recent event (08/18/06; M=4.3) located 20 km northwest of Samara was recorded by two stations (Playa Carrillo and Nicoya) at distances of 25-30 km with maximum acceleration of 0.2g.

Simila, G.; Lafromboise, E.; McNally, K.; Quintereo, R.; Segura, J.

2007-12-01

251

Seismic Strong Motion Array Project (SSMAP) to Record Future Large Earthquakes in the Nicoya Peninsula area, Costa Rica  

NASA Astrophysics Data System (ADS)

The seismic strong motion array project (SSMAP) for the Nicoya Peninsula in northwestern Costa Rica is composed of 10 13 sites including Geotech A900/A800 accelerographs (three-component), Ref-Teks (three- component velocity), and Kinemetric Episensors. The main objectives of the array are to: 1) record and locate strong subduction zone mainshocks [and foreshocks, "early aftershocks", and preshocks] in Nicoya Peninsula, at the entrance of the Nicoya Gulf, and in the Papagayo Gulf regions of Costa Rica, and 2) record and locate any moderate to strong upper plate earthquakes triggered by a large subduction zone earthquake in the above regions. Our digital accelerograph array has been deployed as part of our ongoing research on large earthquakes in conjunction with the Earthquake and Volcano Observatory (OVSICORI) at the Universidad Nacional in Costa Rica. The country wide seismographic network has been operating continuously since the 1980's, with the first earthquake bulletin published more than 20 years ago, in 1984. The recording of seismicity and strong motion data for large earthquakes along the Middle America Trench (MAT) has been a major research project priority over these years, and this network spans nearly half the time of a "repeat cycle" (50 years) for large (Ms 7.5- 7.7) earthquakes beneath the Nicoya Peninsula, with the last event in 1950. Our long time co-collaborators include the seismology group OVSICORI, with coordination for this project by Dr. Ronnie Quintero and Mr. Juan Segura. Numerous international investigators are also studying this region with GPS and seismic stations (US, Japan, Germany, Switzerland, etc.). Also, there are various strong motion instruments operated by local engineers, for building purposes and mainly concentrated in the population centers of the Central Valley. The major goal of our project is to contribute unique scientific information pertaining to a large subduction zone earthquake and its related seismic activity when the next large earthquake occurs in Nicoya. A centralized data base will be created within the main seismic network files at OVSICORI, with various local personnel working in teams that will be responsible to collect data within 3 days following a large mainshock.

Simila, G.; McNally, K.; Quintero, R.; Segura, J.

2006-12-01

252

Executive Summary of Vision and Options for the Future of the US National Strong-Motion Program  

USGS Publications Warehouse

These reports are presented in response to a charge of the Earthquake Hazards Reduction Program (EHRP) Program Council of the U.S. Geological Survey to 'define the future of the USGS National Strong-Motion Program (NSMP)' (Appendix A). The council requested that a 'Vision Paper' and an 'Options Document' be prepared. Each of these reports is a separate document. The 'Executive Summary' of both reports is presented here under separate cover. The content of the reports and the executive summary is organized to the extent possible according to the main charges of the EHRP Program Council. Detailed evaluation of charges and questions posed by the Council with the benefit of modern GIS tools and the recent deliberations of three national workshops have yielded substantial new insight regarding the status of strong-motion measurement in the US. These reports are intended as an objective evaluation of the nation's need and capability to record the next major earthquake at locations of most significance for public safety.

1997-01-01

253

Complexity of the Mw 6.3 2009 L'Aquila (central Italy) earthquake: 2. Broadband strong motion modeling  

NASA Astrophysics Data System (ADS)

Near-fault strong-ground motions (0.1-10 Hz) recorded during the Mw 6.3 2009 L'Aquila earthquake exhibit great spatial variability. Modeling the observed seismograms allows linking distinct features of the observed wavefield to particular source and propagation effects and provides insights on strong motion complexity from this moderate magnitude event. We utilize a hybrid integral-composite approach based on a k-square kinematic rupture model, combining low-frequency coherent and high-frequency incoherent source radiation and providing omega-squared source spectral decay. Several source model features, proven to be stable by means of an uncertainty analysis in the preceding low-frequency (<0.2 Hz) multiple finite-extent source inversion (Paper 1), were constrained. Synthetic Green's functions are calculated in a 1D-layered crustal model including 1D soil profiles to account for site-specific response (where available). The results show that although the local site effects improve the modeling, the spatial broadband ground-motion variability is to large extent controlled by the rupture kinematics. The modeling thus confirms and further constraints the source model features, including the position and slip amount of the two main asperities, the largest asperity time delay and the rupture velocity distribution on the fault. Furthermore, we demonstrate that the crossover frequency dividing the coherent and incoherent wavefield, often considered independent on the station position, has to be variable in order to adequately reproduce both near and far station recordings. This suggests that the incoherency of the radiated wavefield is controlled by the wave-propagation phenomena and/or the initial updip rupture propagation was very smooth (coherent) up to relatively high frequencies (>2 Hz).

Ameri, G.; Gallovi?, F.; Pacor, F.

2012-04-01

254

Utilization of strong motion data for damage assessment of reinforced concrete bridges  

NASA Astrophysics Data System (ADS)

This study investigates the performance of a vibration-based technique for damage assessment of reinforced concrete bridges from non-stationary and incomplete acceleration response measurements during high amplitude earthquakes. The proposed damage assessment technique is targeted to be used in the aftermath of a major earthquake event to rapidly and remotely assess the functionality status of the bridge and identify potential hazards to the public safety. As the first step of the procedure, time-frequency representation of the response of the bridge is achieved by applying stochastic subspace system identification technique to successive and overlapping windows of the response measurements. The timefrequency representation is then used to identify the longest ending segment of the response with relatively stable modal properties. Post-earthquake experimental modal properties of the bridge are subsequently extracted from the identified stable portion of the response. These properties are used to estimate the amount of degradation in stiffness of the structural elements through an optimization-based finite element model updating technique. The Genetic Algorithm optimization technique is used to update the stiffness properties of the structural elements by minimizing the error between analytical and experimental modal properties of the bridge. The proposed damage assessment procedure is applied to experimental data from a large-scale shake table test during which a quarter-scale model of a reinforced concrete bridge was subjected to a series of earthquake and low-amplitude white noise base excitations. The meaningful agreement between the stiffness correction factors identified from both types of motions at the same damage state of the bridge demonstrates that the proposed procedure can effectively be applied for post-earthquake damage assessment of the bridges from nonlinear responses during high amplitude earthquakes.

Baghaei, Reza; Feng, Maria Q.

2011-04-01

255

Kinematic inversion of strong motion data using a Gaussian parameterization of the slip: application to the Iwate-Miyagi earthquake.  

NASA Astrophysics Data System (ADS)

We present a non linear technique to invert strong motion records with the aim of obtaining the final slip and the rupture velocity distributions on the fault plane. Kinematic inversion of strong motion data is an ill-conditioned inverse problem, with several solutions available also in the case of noise-free synthetic data (Blind test on earthquake source inversion,http://www.seismo.ethz.ch/staff/martin/BlindTest.html).On the other hand, complete dynamic inversion still looks impracticable, because of an unclear understanding of the physical mechanisms controlling the energy balance at the rupture tip and a strong correlation between the initial stress field and the parameters of the constitutive law. Hence a strong effort is demanded to increase the robustness of the inversion, looking at the details of the slip and rupture velocity parameterization, at the global exploration techniques, at the efficiency of the cost-function in selecting solutions, at the synthesis process in retrieving the stable features of the rupture. In this study, the forward problem, i.e. the ground motion simulation, is solved evaluating the representation integral in the frequency domain by allowing possible rake variation along the fault plane. The Green's tractions on the fault are computed using the discrete wave-number integration technique that provides the full wave-field in a 1D layered propagation medium. The representation integral is computed through a finite elements technique on a Delaunay triangulation of the fault plane. The rupture velocity is finally defined on a coarser regular grid and rupture times are computed by integration of the eikonal equation. For the inversion, the slip distribution is parameterized by 2D overlapping Gaussian functions, which can easily relate the spectrum of the possible solutions with the minimum resolvable wavelength, related to source-station distribution and data processing. The inverse problem is solved by a two-step procedure aimed at separating the computation of the rupture velocity from the evaluation of the slip distribution, the latter being a linear problem, when the rupture velocity is fixed. The non-linear step is solved by optimization of an L2 misfit function between synthetic and real seismograms, and solution is searched by the use of the Neighbourhood Algorithm. The conjugate gradient method is used to solve the linear step instead. The developed methodology has been applied to the M7.2, Iwate Nairiku Miyagi, Japan, earthquake that was recorded by the K-net and Kik-net accelerometric networks.

Lucca, Ernestina; Festa, Gaetano; Emolo, Antonio

2010-05-01

256

An initial model of seismic microzonation of Sikkim Himalaya through thematic mapping and GIS integration of geological and strong motion features  

Microsoft Academic Search

Seismic microzonation and hazard mapping was undertaken in the Sikkim Himalaya with local site conditions and strong ground motion attributes incorporated into a geographic information system. A strong motion network in Sikkim consisting of 9 digital accelerographs recorded more than 100 events during 1998–2002, of which 72 events are selected with signal-to-noise ratios ?3 for the estimation of site response

Sankar Kumar Nath

2005-01-01

257

Finite Fault Kinematic Rupture Model of the 2009 Mw6.3 L'Aquila Earthquake from Inversion of Strong Motion, GPS and InSAR Data  

Microsoft Academic Search

The Mw6.3 L'Aquila earthquake of April 6, 2009 is the M>6 normal faulting earthquake with the best near-source strong motion observations. Seventeen strong motion accelerographs are within 50km of the surface projection of the fault plane. Of these ten are within 20 km, and four of them are right above the fault plane. The data coverage is further improved with

T. E. Yano; G. Shao; Q. Liu; C. Ji; R. J. Archuleta

2009-01-01

258

Curved ducts with strong secondary motion - Velocity measurements of developing laminar and turbulent flow  

NASA Technical Reports Server (NTRS)

Two orthogonal components of velocity and associated Reynolds stresses are determined in a square-sectioned, 90 degree bend of 2.3 radius ratio by utilizing laser-Doppler velocimetry for Reynolds numbers of 790 and 40,000. Results show that boundary layers at the bend inlet of 0.25 and 0.15 of the hydraulic diameter create secondary velocity maxima of 0.6 and 0.4 of the bulk flow velocity, respectively. It is concluded that the boundary layer thickness is important to the flow development, mainly in the first half of the bend, especially when it is reduced to 0.15 of the hydraulic diameter. Smaller secondary velocities are found for turbulent flow in an identical duct with a radius ratio of 7.0 than in the strongly curved bend, although their effect is more important to the streamwise flow development because of the smaller pressure gradients. In addition, the detail and accuracy of the measurements make them suitable for evaluation of numerical techniques and turbulence models.

Taylor, A. M. K. P.; Whitelaw, J. H.; Yianneskis, M.

1982-01-01

259

A PHYSICAL MODEL OF THE EFFECT OF A SHALLOW WEAK LAYER ON STRONG GROUND MOTION FOR STRIKE-SLIP RUPTURES  

SciTech Connect

We report results of foam-rubber modeling of the effect of a shallow weak layer on ground motion from strike-slip ruptures. Computer modeling of strong ground motion from strike-slip earthquakes has involved somewhat arbitrary assumptions about the nature of slip along the shallow part of the fault (e.g., fixing the slip to be zero along the upper 2 kilometers of the fault plane) in order to match certain strong motion accelerograms. Most modeling studies of earthquake strong ground motion have used what is termed kinematic dislocation modeling. In kinematic modeling the time function for slip on the fault is prescribed, and the response of the layered medium is calculated. Unfortunately, there is no guarantee that the model and the prescribed slip are physically reasonable unless the true nature of the medium and its motions are known ahead of time. There is good reason to believe that in many cases faults are weak along the upper few kilometers of the fault zone and may not be able to maintain high levels of shear strain required for high dynamic energy release during earthquakes. Physical models of faulting, as distinct from numerical or mathematical models, are guaranteed to obey static and dynamic mechanical laws. Foam-rubber modeling studies have been reported in a number of publications. The object of this paper is to present results of physical modeling using a shallow weak layer, in order to verify the physical basis for assuming a long rise time and a reduced high frequency pulse for the slip on the shallow part of faults. It appears a 2-kilometer deep, weak zone along strike-slip faults could indeed reduce the high frequency energy radiated from shallow slip, and that this effect can best be represented by superimposing a small amplitude, short rise-time pulse at the onset of a much longer rise-time slip. A weak zone was modeled by inserting weak plastic layers of a few inches in thickness into the foam rubber model. For the 15 cm weak zone the average pulse is reduced by a factor of 0.46. The factor for the 20 cm case reduction is 0.11. For the 30 cm case it is 0.045. From these results we can see that, the thicker the weak layer, the more difficult it is for a short rise-time acceleration pulse to push its way through the weak layer to the surface. This is thus an approximate justification for reducing the high frequency radiation from shallower parts of strike-slip faults if it is known that the shallow part of the fault is weak or has not stored up shear stress.

JAMES N. BRUNE AND ABDOLRASOOL ANOOSHEHPOOR

1998-02-23

260

Motion.  

ERIC Educational Resources Information Center

This issue of Exploratorium Magazine focuses on the topic of motion. Contents include: (1) "First Word" (Zach Tobias); (2) "Cosmic Collisions" (Robert Irion); (3) "The Mobile Cell" (Karen E. Kalumuck); (4) "The Paths of Paths" (Steven Vogel); (5) "Fragments" (Pearl Tesler); (6) "Moving Pictures" (Amy Snyder); (7) "Plants on the Go" (Katharine…

Brand, Judith, Ed.

2002-01-01

261

ISET Journal of Earthquake Technology, Paper No. 506, Vol. 46, No. 3-4, Sept.-Dec. 2009, pp. 125132 SIMULATION OF STRONG GROUND MOTIONS OF WENCHUAN  

E-print Network

the structural aseismic capability. KEYWORDS: Wenchuan, Stochastic Finite-Fault Method, Near-Fault Strong GroundISET Journal of Earthquake Technology, Paper No. 506, Vol. 46, No. 3-4, Sept.-Dec. 2009, pp. 125­132 SIMULATION OF STRONG GROUND MOTIONS OF WENCHUAN EARTHQUAKE BY STOCHASTIC FINITE-FAULT METHOD Guoxin Wang

Gupta, Vinay Kumar

262

An estimation of sediment thickness using Sp converted phases in Kaoping, Taiwan  

NASA Astrophysics Data System (ADS)

The Kaoping area is a triangle alluvial plain, located in the southwestern Taiwan. Accelerograms recorded from 1991 to 2010 by the Taiwan Strong Motion Instrumentation Program (TSMIP) stations are used to study the thickness variations of the Quaternary alluviums beneath Kaoping area by examining the Sp converted phase. Travel-time difference of S and Sp phases is used to estimate the sediment thickness. With highly seismicity activities and dense strong motion array, this technique has been used in Lan-Yang Plain and Chia-Nan Plain. In this study we focus on Kaoping region in order to discuss the underground structures in the study region. The major targets are to determine the location of Chaochou fault and Sp phase is converted from which formation boundary. Results show that the thickness become thicker toward the west in Kaohsiung area, and the thickness become thinner toward east. Details will be presented in this study.

Chuang, M.; Wu, Y.; Wei, J.; Chang, C.

2011-12-01

263

Source parameters of the 2013 Lushan, Sichuan, Ms7.0 earthquake and estimation of the near-fault strong ground motion  

NASA Astrophysics Data System (ADS)

Abstract: The April 20, 2013 Ms 7.0 earthquake in Lushan city, Sichuan province of China occurred as the result of east-west oriented reverse-type motion on a north-south striking fault. The source location suggests the event occurred on the Southern part of Longmenshan fault at a depth of 13km. The Lushan earthquake caused a great of loss of property and 196 deaths. The maximum intensity is up to VIII to IX at Boxing and Lushan city, which are located in the meizoseismal area. In this study, we analyzed the dynamic source process and calculated source spectral parameters, estimated the strong ground motion in the near-fault field based on the Brune's circle model at first. A dynamical composite source model (DCSM) has been developed further to simulate the near-fault strong ground motion with associated fault rupture properties at Boxing and Lushan city, respectively. The results indicate that the frictional undershoot behavior in the dynamic source process of Lushan earthquake, which is actually different from the overshoot activity of the Wenchuan earthquake. Based on the simulated results of the near-fault strong ground motion, described the intensity distribution of the Lushan earthquake field. The simulated intensity indicated that, the maximum intensity value is IX, and region with and above VII almost 16,000km2, which is consistence with observation intensity published online by China Earthquake Administration (CEA) on April 25. Moreover, the numerical modeling developed in this study has great application in the strong ground motion prediction and intensity estimation for the earthquake rescue purpose. In fact, the estimation methods based on the empirical relationship and numerical modeling developed in this study has great application in the strong ground motion prediction for the earthquake source process understand purpose. Keywords: Lushan, Ms7.0 earthquake; near-fault strong ground motion; DCSM; simulated intensity

Meng, L.; Zhou, L.; Liu, J.

2013-12-01

264

Observations and Modeling of Strong Ground Motions for the 23 October 2011 Mw 7.1 Van, Turkey, Earthquake  

NASA Astrophysics Data System (ADS)

The October 23 2011 Van earthquake occurred at 13:41 p.m. local time in the eastern Turkey with an epicenter at 42.43oN, 38.69oE, about 16 km kilometers north-northeast of the city Van. The hypocenter is located to the north of the Bitlis structure zone, a convergence zone between the Arabian and Eurasian plates in the Eastern Anatolia. According to the Kandilli Observatory and Earthquake Research Institute, KOERI, the earthquake nucleated at a shallow depth of 5 km, and had a local magnitude Ml 6.6. A moment magnitude Mw 7.1 was computed with a 16 km hypocentral depth using regional broadband waveforms by United States Geological Survey, USGS. The size of the rupture has been estimated by USGS as 60 km x 20 km, consistent with the observed distribution of aftershocks, on a WSW-ENE orientated fault plane with a dip of about 35°. There have been eight aftershocks greater than magnitude 5.0; six occurred within 5 days after the mainshock.Two weeks after the mainshock, another earthquake with magnitude Mw 5.7 and a depth of 9.4km was reported near Van on November 9 at 21:23 local time. it caused 40 deaths and hundreds of injured. Its different focal mechanism and its location centered 16 km south of Van provocating a debate if the earthquake of November 9 was an aftershock of the October 23 earthquake. The stress changes in the region due to this earthquake may interact with other faults in the area, and may lead to a heightened chance of further large earthquakes in the months and years ahead. Therefore we partly consentrate on how applicable the static Coulomb stress trigering mechanism to the 2011 Van Lake afterschock. Furthermore substantial effort has been directed toward undestanding the high frequency ground motion characteristics associated with the seismic sequence. In this perspective we aim to reproduce the high frequency portion of the strong ground motion recordings obtained during the earthquake. The earthquake's complex nature and the absence of the observed data near field distances motivated us simulating variability of the near-source ground motion and to account for the extended source properties, such as earthquake rupture propagation and asperities distribution on the fault plane.

Akinci, A.; Antonioli, A.

2012-04-01

265

Simulation of Strong Ground Motion Based on Conventional Empirical Green s Functions In the Michoacán State, Mexico  

NASA Astrophysics Data System (ADS)

In the present work, we study the state of Michoacán, one of the most important seimogenic zones in Mexico. Three kinds of sources exist in the state, producing tectonic earthquakes, volcanic earthquakes, and events due to local faults in the region. For this reason, it is of vital importance the study of source parameters in the Michoacán state. In this work in particular we applied the simulation of strong ground motions by the conventional empirical Green s functions proposed by Irikura (1986). We installed a temporary network consisting of 6 accelerograph stations across the state, at the following locations: Faro de Brucerías, Aguililla, Apatzingán, Pátzcuaro, Morelia, and Maravatío. The stations form a line that is perpendicular to the coastline and has a total length of 366 km, while the distance between neighboring stations varies from 60 to 80 km. Among all the seismic events recorded at this temporary network, we select 2 events originated along the coastline of Michoacán (May the 2007), with moment magnitudes of 4.3 and 5.1 Mw. In order to calibrate the model, the earthquake of May 31, 2007 (M 5.1) was simulated using the aftershock of May 27 of that year (M 4.3) with satisfactory results, following the same method and considering the ?2 spectral model with constant stress drop. Later, we calculated six scenarios for a postulate earthquake of M 7.4. From the six scenarios the largest peak ground accelerations for each station were, 83 cm/s2 in Faro de Brucerías , 15.4 cm/s2 in Apatzingán, 23 cm/s2 in Pátzcuaro, 3.7 cm/s2 in Morelia and Maravatio con 3.0 cm/s2 . One limitation of this study is that we used relatively small-magnitude earthquakes. This was a consequence of the relatively short operation period of the temporary network, which had to be limited to 3 months. To improve these simulations it is necessary to have more information about rupture processes of the recorded earthquakes. And likewise, information of future earthquakes in the region is needed in order to improve prediction models as the one presented in this work. That information will be useful to minimize uncertainty and to better understand the parameters involved in the strong-motion simulations.

Vazquez Rosas, R.; Aguirre Gonzalez, J. J.; Mijares Arellano, H. H.

2012-12-01

266

The 4th February 1997 Bojnurd (Garmkhan) Earthquake in NE Iran: Field, Teleseismic, and Strong-Motion Evidence for Rupture Directivity Effects on a Strike-Slip Fault  

Microsoft Academic Search

The Bojnurd region of NE Iran experienced a Mw 6.4 earthquake on February 4, 1997. By combining results from teleseismic body-waveform analysis, field observations of structural damage, coseismic deformation, geomorphology, and analysis of the resulting strong ground-motions, we build a coherent picture of the faulting associated with this earthquake. The earthquake resulted from almost pure right-lateral strike-slip motion (0.5–1.0 m),

James Hollingsworth; James Jackson; John E. Alarcón; Julian J. Bommer; Mohammad Javad Bolourchi

2007-01-01

267

Microfracture processes in the breakdown zone during dynamic shear rupture inferred from laboratory observation of near-fault high-frequency strong motion  

Microsoft Academic Search

High-frequency velocities are measured during stick-slip motion in the immediate vicinity of a fault in a granite sample to reveal the microscopic process taking place in the breakdown zone defined in the slip-weakening model. It is found that 1) the onset time of the observed strong motion approximately coincides with the local rupture onset time, 2) the observed near-fault high-frequency

Naoyuki Kato; Kiyohiko Yamamoto; Tomowo Hirasawa

1994-01-01

268

Combining Broadband, Strong Motion, and other geophysical data in real time data acquisition and processing at the Swiss Seismological Service SED  

NASA Astrophysics Data System (ADS)

The Swiss Seismological Service (SED) operates one of the densest seismic broadband networks in Europe with 27 STS2 stations transmitting 24 bit 120sps data in real time. In addition the SED operates a network of 77 strong-motion recorders (65 free-field, 12 on hard rock co-located with broadband sensors). At 16 of the free-field sites and the 12 hard-rock sites Episensor accelerometers and 24 bit digitizers are installed and data is also transmitted in real time, while the other stations are equipped with 1990-era Geosig strong motion sensors, 16 bit A/D converters, and dial-up telephone links. Over the next 10years it is planned to replace those older strong motion stations with Episensors, 24 bit digitizers, and real-time data links, and to install an additional 51 free-field stations of that type. Past experience has shown that the strong motion data is very useful for refining the hypocentral parameters especially for smaller earthquakes, so in future all new strong motion channels will be integrated into the real-time processing.According to the SED open data policy all this data will be freely available e.g. through ORFEUS. Furthermore, new regional experiments in Switzerland (in particular COGEAR, "Coupled seismogenic Geohazards in Alpine Regions") will provide additional data from dense temporary deployments of strong motion stations and real-time GPS, but also from other geophysical methods like geochemical and magnetotelluric measurements with significantly different data types and sampling rates. Apart from the challenges of integrated acquisition and quasi-real-time processing of all that data the provision of efficient access to data streams and station metadata requires new concepts of web-based data visualisation and retrieval implementations (e.g. webmap services).

Clinton, J.; Haslinger, F.; Fäh, D.; Zweifel, P.; Schnabel, O.; Giardini, D.

2009-04-01

269

A teleseismic study of the 2002 Denali fault, Alaska, earthquake and implications for rapid strong-motion estimation  

USGS Publications Warehouse

Slip histories for the 2002 M7.9 Denali fault, Alaska, earthquake are derived rapidly from global teleseismic waveform data. In phases, three models improve matching waveform data and recovery of rupture details. In the first model (Phase I), analogous to an automated solution, a simple fault plane is fixed based on the preliminary Harvard Centroid Moment Tensor mechanism and the epicenter provided by the Preliminary Determination of Epicenters. This model is then updated (Phase II) by implementing a more realistic fault geometry inferred from Digital Elevation Model topography and further (Phase III) by using the calibrated P-wave and SH-wave arrival times derived from modeling of the nearby 2002 M6.7 Nenana Mountain earthquake. These models are used to predict the peak ground velocity and the shaking intensity field in the fault vicinity. The procedure to estimate local strong motion could be automated and used for global real-time earthquake shaking and damage assessment. ?? 2004, Earthquake Engineering Research Institute.

Ji, C.; Helmberger, D.V.; Wald, D.J.

2004-01-01

270

Robust features of the source process for the 2004 Parkfield, California, earthquake from strong-motion seismograms  

NASA Astrophysics Data System (ADS)

We explore a recently developed procedure for kinematic inversion based on an elliptical subfault approximation. In this method, the slip is modelled by a small set of elliptical patches, each ellipse having a Gaussian distribution of slip. We invert near-field strong ground motion for the 2004 September 28 Mw 6.0 Parkfield, California, earthquake. The data set consists of 10 digital three-component 18-s long displacement seismograms. The best model gives a moment of 1.21 × 1018 N m, with slip on two distinct ellipses, one with a high-slip amplitude of 0.91 m located 20 km northwest of the hypocentre. The average rupture speed of the rupture process is ˜2.7 km s-1. We find no slip in the top 5 km. At this depth, a lineation of small aftershocks marks the transition from creeping above to locked below, in the interseismic period. The high-slip patch coincides spatially with the hypocentre of the 1966 Mw6.0 Parkfield, California, earthquake. The larger earthquakes prior to the 2004 Parkfield earthquake and the aftershocks of the 2004 earthquake (Mw > 3) also lie around this high-slip patch, where our model images a sharp slip gradient. This observation suggests the presence of a permanent asperity that breaks during large earthquakes, and has important implications for the slip deficit observed on the Parkfield segment, which is necessary for reliable seismic hazard assessment.

Twardzik, C.; Madariaga, R.; Das, S.; Custódio, S.

2012-12-01

271

3D Modeling of Strong Ground Motion in the Pacific Northwest From Large Earthquakes in the Cascadia Subduction Zone  

NASA Astrophysics Data System (ADS)

The Cascadia subduction zone in the Pacific Northwest, USA, generates Great (megathrust) earthquakes with a recurrence period of about 500 years, most recently the M~9 event on January 26, 1700. Since no earthquake of such magnitude has occurred in the Pacific Northwest since the deployment of strong ground motion instruments, a large uncertainty is associated with the ground motions expected from such event. To decrease this uncertainty, we have carried out the first 3D simulations of megathrust earthquakes (Mw8.5 and Mw9.0) rupturing along the Cascadia subduction zone. The simulations were carried out in a recently developed 3D velocity model of the region of dimensions 1050 km by 550 km, discretized into 2 billion 250 m3 cubes with a minimum S-wave velocity of 625 m/s. The model includes the subduction slab, accretionary sediments, local sedimentary basins, and the ocean layer. About 6 minutes of wave propagation for each scenario consumed about 24 Wall-clock hours using a parallel fourth-order finite-difference method with 1600 processors on the San Diego Supercomputer Center Datastar supercomputer. The source descriptions for the Mw9.0 scenarios were designed by mapping the inversion results for the December 26, 2004 M9+ Sumatra-Andaman Islands earthquake (Ji, 2006) onto a 950 km by 150 km large rupture for the Pacific Northwest model. Simulations were carried out for hypocenters located toward the northern and southern ends of the subduction zone. In addition, we simulated two M8.5 events with a source area of 275 km by 150 km located in the northern and central parts of the model area. The sources for the M8.5 events were generated using the pseudo-dynamic model by Guatteri et al. (2004). All sources used spatially-variable slip, rise time and rupture velocity. Three major metropolitan areas are located in the model region, namely Seattle (3 million+ people), Vancouver (2 million+ people), and Portland (2 million+ people), all located above sedimentary basins amplifying the waves incident from the subduction zone. The estimated peak ground velocities (PGVs) for frequencies less than 0.5 Hz vary significantly with the assumed rise time. Using a mean rise of 32 s, as estimated from source inversion of the 2004 M9+ Sumatra-Andeman event (Ji, 2006), PGVs reached 40 cm/s in Seattle and 10 cm/s in Vancouver and Portland. However, if the mean rise time is decreased to about 14 s, as suggested by the empirical regression by Somerville et al. (1999), PGVs are increased by 2-3 times at these locations. For the Mw8.5 events, PGVs would reach about 10 cm/s in Seattle, and about 5 cm/s in Vancouver and Portland. Combined with extended duration of the shaking exceeding 1 minute for the Mw8.5 events and 2 minutes for the Mw9 events, these long-period ground motions may inflict significant damage on the built environment, in particular on the highrises in downtown Seattle. However, the strongest shaking arrives 1-2 minutes after the earthquake nucleates, indicating that an early warning system in place may help mitigate loss of life in case of a megathrust earthquake in the Pacific Northwest. Additional efforts should analyse the simulated displacements on the ocean bottom for tsunami generation potential.

Olsen, K. B.; Geisselmeyer, A.; Stephenson, W. J.; Mai, P. M.

2007-12-01

272

Characterized Source Model and Strong Ground Motion Simulation for the 2004 Mid Niigata Prefecture (Niigata-ken Chuetsu) Earthquake Based on Empirical Site Amplification and Phase Effects  

NASA Astrophysics Data System (ADS)

In this article, a characterized source model is proposed for the 2004 Mid Niigata Prefecture, Japan, earthquake (MJ=6.8) by using the stochastic Green's function method, taking into account the site specific amplification and phase characteristics. The strong motions are simulated based on the source model with four asperities, referring to the result of waveform inversion. The simulated ground motions are well consistent with the observed records. It is found from the simulation that the large-amplitude velocity-pulses observed at K-NET NIG019 are generated by small asperities nearby the hypocenter. Furthermore, validity of the strong motion simulation technique using site specific phase characteristics is studied. The result indicates the importance of using the site-specific phase characteristics for reliable response analyses of structures.

Sakai, Kimitoshi; Nozu, Atsushi

273

The July 12, 1993, Hokkaido-Nansei-Oki, Japan, earthquake: Coseismic slip pattern from strong-motion and teleseismic recordings  

USGS Publications Warehouse

We employ a finite fault inversion scheme to infer the distribution of coseismic slip for the July 12, 1993, Hokkaido-Nansei-Oki earthquake using strong ground motions recorded by the Japan Meteorological Agency within 400 km of the epicenter and vertical P waveforms recorded by the Global Digital Seismograph Network at teleseismic distances. The assumed fault geometry is based on the location of the aftershock zone and comprises two fault segments with different orientations: a northern segment striking at N20??E with a 30?? dip to the west and a southern segment with a N20??W strike. For the southern segment we use both westerly and easterly dip directions to test thrust orientations previously proposed for this portion of the fault. The variance reduction is greater using a shallow west dipping segment, suggesting that the direction of dip did not change as the rupture propagated south from the hypocenter. This indicates that the earthquake resulted from the shallow underthrusting of Hokkaido beneath the Sea of Japan. Static vertical movements predicted by the corresponding distribution of fault slip are consistent with the general pattern of surface deformation observed following the earthquake. Fault rupture in the northern segment accounts for about 60% of the total P wave seismic moment of 3.4 ?? 1020 N m and includes a large circular slip zone (4-m peak) near the earthquake hypocenter at depths between 10 and 25 km. Slip in the southern segment is also predominantly shallower than 25 km, but the maximum coseismic displacements (2.0-2.5 m) are observed at a depth of about 5 km. This significant shallow slip in the southern portion of the rupture zone may have been responsible for the large tsunami that devastated the small offshore island of Okushiri. Localized shallow faulting near the island, however, may require a steep westerly dip to reconcile the measured values of ground subsidence.

Mendoza, C.; Fukuyama, E.

1996-01-01

274

High-frequency source imaging of the 2011 October 23 Van (Eastern Turkey) earthquake by backprojection of strong motion waveforms  

NASA Astrophysics Data System (ADS)

We backproject strong motion waveforms to image the rupture process of the 2011 October 23 Van (Mw 7.1) earthquake. We show that the followed backprojection approach is applicable for studying earthquake sources with a complex and uncertain fault geometry. It is especially suitable for cases where the implementation of conventional source inversion methods is difficult due to incomplete data coverage from local networks. Normalized high frequency (HF, 2-8 Hz) S-waveform envelopes from recordings on local Turkish and Iranian stations are used to scan a pre-defined 3-D source volume over time. The envelopes are forced to focus at the hypocentre by applying the appropriate station corrections, estimated from waveform cross-correlation. We image two distinct sources of HF radiation during the earthquake rupture at depths between 10 and 12 km. The first one, a few seconds after the rupture initiation, is located near the hypocentre. The second, at least 13 km southwestwards, follows 3.5 s later. While a continuous rupture propagation is not clearly imaged, the average rupture speed is 3.5 km s-1. Synthetic tests show that both HF sources could be resolved adequately from this station distribution. Both sources of HF are located at the edge of large slip patches, imaged by seismic and geodetic inversions. The existence of a complex fault geometry, like a pair of en-echelon reverse faults, explains the radiation of HF energy. The first source is attributed to a stopping phase of the eastern subfault or a possible change on a single fault geometry. The second HF source is produced from the abrupt cease of rupture at the shallow part of the upper crust.

Evangelidis, C. P.; Kao, H.

2014-02-01

275

Strong motion envelope modelling of the source of the Chamoli earthquake of March 28, 1999 in the Garhwal Himalaya, India  

NASA Astrophysics Data System (ADS)

Garhwal Himalaya has been rocked by two major earthquakes in the span of just eight years, viz. Uttarkashi earthquake of 20th Oct, 1991 and Chamoli earthquake of 28th March, 1999. Chamoli earthquake of March 28, 1999 was recorded at 11 different stations of a strong motion array installed in the epicentral region. The maximum peak ground acceleration (353 cm/s2) was recorded at an accelerograph located at Gopeshwar. The data from eleven stations has been used for comparison with the simulated acceleration envelopes due to a model of the rupture responsible for this earthquake. For simulation of acceleration envelope the method of Midorikawa (1993) has been modified for its applicability to Himalayan region. This method has earlier been used by Joshi and Patel (1997) and Joshi (1999) for the studyof Uttarkashi earthquake of 20th Oct, 1991. The same method has been used for study of Chamoli earthquake. Layered earth crust has been introduced in place of homogeneous one in this method. The model of rupture is placed at a depth of 12 km below the Munsiari thrust for modelling Chamoli earthquake. Peak ground acceleration was calculated from simulated acceleration envelope using layered as well as homogeneous earth crust. For the rupture placed in a layered crust model peak ground acceleration of order 312 cm/s2 was simulated at Gopeshwar which is quite close to actually recorded value. The comparison of peak ground acceleration values in terms of root mean square error at eleven stations suggests that the root mean square error is reduced by inclusion of a layered earth crust in place of homogeneous earth crust.

Joshi, A.

276

Predicting strong motion parameters for the Chamoli earthquake of 28 th March, 1999, Garhwal Himalaya, India, from simplified finite fault model  

Microsoft Academic Search

State of Uttaranchal in the northern part of India in the Garhwal Himalaya was hit by the Chamoli earthquake on 28th March, 1999 (GMT). This earthquake was recorded on a strong motion array installed in this region. The maximum peak ground acceleration of 353 cm\\/sec2 was recorded at an accelerograph located at the Gopeshwar station at an approximate epicentral distance

A. Joshi

2003-01-01

277

Characterized Fault Model of Scenario Earthquake Caused by the Itoigawa-Shizuoka Tectonic Line Fault Zone in Central Japan and Strong Ground Motion Prediction  

Microsoft Academic Search

Based on the existing ideas on characterizing complex fault rupture process, we constructed four different characterized fault models for predicting strong motions from the most likely scenario earthquake along the active fault zone of the Itoigawa-Shizuoka Tectonic Line in central Japan. The Headquarters for Earthquake Research Promotion in Japanese government (2001) estimated that the earthquake (8 +\\/- 0.5) has the

T. Sato; K. Dan; K. Irikura; M. Furumura

2001-01-01

278

Bulletin of the SeismologicalSociety of America. Vol. 67, No. 2, pp. 315-330. April 1977 A STUDY OF THE STRONG GROUND MOTION OF THE BORREGO  

E-print Network

OF THE STRONG GROUND MOTION OF THE BORREGO MOUNTAIN, CALIFORNIA, EARTHQUAKE BY THOMASH. HEATONAND DONALD V polarized displacement, as recorded at El Centro, of the April 9, 1968 Borrego Mountain earthquake man-made structures have become larger and because seismologists have become increasingly interested

Greer, Julia R.

279

Attenuation Relationship of Arias Intensity for Taiwan  

NASA Astrophysics Data System (ADS)

Arias intensity (AI) reflects the complete acceleration time history duration of ground vibrations. It correlates well with several commonly used demand measure of structural performance, liquefaction, and seismic slope stability. A good attenuation equation can reflect the characteristics of the ground-motion attenuation for a region, and can be used to predict the ground-motion value of a specific site for seismic resistance design. This study analyzed two local empirical attenuation relationships, one for the crustal earthquakes and the other for the subduction zone earthquakes, based on the strong ground-motion data from TSMIP and SMART1 array in Taiwan. Maximum likelihood method and mixed-effect model were used with non-linear regression analyses to determine coefficients. The result shows that adding terms of Vs30 and focal mechanism can effectively reduce the standard deviation in the attenuation models. To compare with other AI attenuation equations, the AI value predicted by our crustal earthquake attenuation equation is higher in the near field and is lower in the far field than the researches in other regions. The subduction zone earthquake attenuation equation predicts higher AI value than the crustal earthquake attenuation equation does.

Sung, C.; Hsieh, P.; Lin, P.; Lee, C.

2008-12-01

280

Brownian Motion as Limit of Random Walk Claim 1 A (, ) Brownian motion is the limiting case of  

E-print Network

Brownian Motion as Limit of Random Walk Claim 1 A (µ, ) Brownian motion is the limiting case, National Taiwan University Page 519 #12;Brownian Motion as Limit of Random Walk (continued) · Assume n t ] = 1 - (2p - 1)2 . c 2014 Prof. Yuh-Dauh Lyuu, National Taiwan University Page 520 #12;Brownian Motion

Lyuu, Yuh-Dauh

281

Strong ground motion data recorded at the Idaho National Laboratory during the 1983 Borah Peak, Idaho earthquake. [Appendix contains plot generated by accelerogram showing peak valves amplitude, response spectra, displacement, veolocity and acceleration  

Microsoft Academic Search

The Idaho National Engineering Laboratory (INEL) is located approximately 80 km southeast of the epicenter for the 1983 M{sub S} 7.3 Borah Peak Idaho earthquake. Thirteen strong-motion accelerographs located at various facilities around the INEL Site recorded strong-ground motions from the Borah Peak earthquake. The strong-motion records were digitized and processed resulting in corrected acceleration, velocity, and displacement time-histories and

S. M. Jackson; J. J. King; D. M. Anderson; G. S. Carpenter; H. A. Adams

1991-01-01

282

Rigorous noise test and calibration check of strong-motion instrumentation at the Conrad Observatory in Austria.  

NASA Astrophysics Data System (ADS)

In the framework of the European InterregIV Italy/Austria project: "HAREIA - Historical and Recent Earthquakes in Italy and Austria" the Central Institute for Meteorology and Geodynamics (ZAMG) and Mathematic and Geosciences Department of University of Trieste (DMG) are upgrading the transfrontier seismic network of South-Eastern Alps with new 12 accelerometric stations to enhance the strong motion instrument density near the Austria/Italy border. Various public institutions of the provinces Alto Adige (Bolzano Province), Veneto (ARPAV) and Friuli Venezia Giulia (Regional Civil Defense) in Italy and in the Austrian province of Tyrol are involved in the project. The site selection was carried out to improve the present local network geometry thus meeting the needs of public Institutions in the involved regions. In Tyrol and Alto Adige some strategic buildings (hospitals and public buildings) have been selected, whereas in Veneto and Friuli Venezia Giulia the sites are in the free field, mainly located near villages. The instruments will be installed in an innovative box, designed by ZAMG, that provides electric and water isolation. The common choice regarding the instrument selection has been the new Kinemetrics Basalt ® accelerograph to guarantee homogeneity with the already installed instrumentation and compatibility with the software already in use at the different seismic institutions in the area. Prior to deployment the equipment was tested at the Conrad Observatory and a common set-up has been devised. The Conrad Observatory, seismically particularly quiet, permits to analyze both the sensor and the acquisition system noise. The instruments were connected to the network and the data sent in real-time to the ZAMG data center in Vienna and the DMG data center in Trieste. The data have been collected in the database and analyzed using signal processing modules PQLX and Matlab. The data analysis of the recordings at the ultra-quiet Conrad Observatory pointed out some differences in the seismic response of the 12 instruments, mainly within the tolerance stated by the factory, and an optimization of a few sensors can be carried out in order to guarantee compatible high quality measurements.

Steiner, R.; Costa, G.; Lenhardt, W.; Horn, N.; Suhadolc, P.

2012-04-01

283

The Seismic Strong Motion Array Project (SSMAP) and the September 5, 2012 Mw=7.6 Nicoya, Costa Rica Earthquake  

NASA Astrophysics Data System (ADS)

Seismic gaps along the subduction zones are locations where large earthquakes have not occurred in a long time. The Cocos plate is subducting beneath the Caribbean plate in Costa Rica, and the Nicoya Peninsula, located in northwestern Costa Rica, has been identified as a seismic gap. The previous major earthquakes in Nicoya occurred on 1853, 1900 and 1950, which indicates about a 50-year recurrence interval for the characteristic earthquake cycle. Since 2006, the seismic strong motion array project (SSMAP) for the Nicoya Peninsula in northwestern Costa Rica has been composed of 10 sites with Geotech A900/A800 accelerographs (three-component) and GPS timing. Our digital accelerographs array has been deployed as part of our ongoing research on large earthquakes, including the potential Nicoya event, in conjunction with the Earthquake and Volcano Observatory (OVSICORI) at the Universidad Nacional in Costa Rica. From 2006 to 2012, 28 events were relocated using the SSMAP and OVSICORI data with moderate magnitudes (4 < Mw< 6.5), and were mainly located in Nicoya Peninsula region. On September 5, 2012, a Mw=7.6 earthquake occurred in the seismic gap and appears to be the expected event based on the 50 years recurrence interval, but was instead 62 years later. The main shock focal mechanism was thrust faulting, propagating downdip, of the Cocos plate in the Middle America trench with strike N54W and dip 20 degrees NE. The mainshock and 15 early aftershocks were relocated by using SSMAP, OVSICORI, and UCSC networks. The final location of the mainshock is 9.671 N and 85.878 W with a depth of 18 km. The maximum accelerations from two A900 stations perpendicular to the trench, Fortuna (distance 112km) and Pedernal (distance 128 km) are: 13.8% and 8.9 % g, respectively. In addition, the October 10 (MW 5.3) and 24(Mw 6.6) aftershocks recorded at Tamarindo (distances 40 km and 70 km, respectively) showed accelerations of 2.4% and 8.2% g; respectively. The mainshock acceleration data from SSMAP, University of Costa Rica, and National Electricity Institute networks were analyzed for a new attenuation relationship: Acceleration = -203 ln(R) + 1110 with M=7.6 and R = hypocentral distance.

Simila, Gerald; Mohammadebrahim, Ehsan; McNally, Karen; Quintero, Ronnie; Segura, Juan

2014-05-01

284

Some Key Features of the Strong-Motion Data from the M 6.0 Parkfield, California, Earthquake of 28 September 2004  

USGS Publications Warehouse

The 2004 Parkfield, California, earthquake was recorded by an extensive set of strong-motion instruments well positioned to record details of the motion in the near-fault region, where there has previously been very little recorded data. The strong-motion measurements obtained are highly varied, with significant variations occurring over only a few kilometers. The peak accelerations in the near fault region range from 0.13g to over 1.8g (one of the highest acceleration recorded to date, exceeding the capacity of the recording instrument The largest accelerations occurred near the northwest end of the inferred rupture zone. These motions are consistent with directivity for a fault rupturing from the hypocenter near Gold Hill toward the northwest. However, accelerations up to 0.8g were also observed in the opposite direction, at the south end of the Cholame Valley near Highway 41, consistent with bilateral rupture, with rupture southeast of the hypocenter. Several stations near and over the rupturing fault recorded relatively weak motions, consistent with seemingly paradoxical observations of low shaking damage near strike-slip faults. This event had more ground-motion observations within 10 km of the fault than many other earthquakes combined. At moderate distances peak horizontal ground acceleration (PGA) values dropped off more rapidly with distance than standard relationships. At close-in distance the wide variation of PGA suggests a distance-dependent sigma may be important to consider. The near-fault ground-motion variation is greater than that assumed in ShakeMap interpolations, based on the existing set of observed data. Higher density of stations near faults may be the only means in the near future to reduce uncertainty in the interpolations. Outside of the near-fault zone the variance is closer to that assumed. This set of data provides the first case where near-fault radiation has been observed at an adequate number of stations around the fault to allow detailed study of the fault-normal and fault-parallel motion and the near-field S-wave radiation. The fault-normal motions are significant, but they are not large at the central part of the fault, away from the ends. The fault-normal and fault-parallel motions drop off quite rapidly with distance from the fault. Analysis of directivity indicates increased values of peak velocity in the rupture direction. No such dependence is observed in the peak acceleration, except for stations close to the strike of the fault near and beyond the ends of the faulting.

Shakal, A.; Haddadi, H.; Graizer, V.; Lin, K.; Huang, M.

2006-01-01

285

The Relation between Seismicity and Active Faults in Northwestern Taiwan  

NASA Astrophysics Data System (ADS)

Northwestern Taiwan is a major economical, transportation and cultural center in our country. Geologically, this region is covered by red soil terraces. These terraces are displaced by several active faults. Seismicity reveals potential of strong ground motion in this region. We deploy a microearthquake network to locate the active faults in the region. The aim of our study is to find the characteristics of seismicity in the Taoyuan, Hsinchu, and Miaoli region, and the relation between seiemicity and active faults. The Central Weather Bureau (CWB) in Taiwan has deployed a short period seismic network in whole Taiwan. Many earthquakes were located by the CWB seismic network, but many small mircoearthquakes occurred in the local area can not be detected. Thus we deploy a temporary seismic network in the area since 2001. Ten stations were deployed. Each station includes an accelerograph with GPS and three component velocity-type sensors. The sampling rate is 200 points/sec. There are two ways to increase the accuracy of the earthquake location. One is to increase the seismic stations in the study area. The other way is to improve the location method. We locate the earthquakes by using the data of both CWB seismic network and our seismic network. The results show most earthquakes occurred in the mountain area in the southeast part of the seismic network. After we relocate the earthquakes, the focal depth changes significantly. Most focal depths are less than fifteen kilometers and become densely clustered.

Lee, C.; Tsai, Y.

2004-12-01

286

INVERSION OF STRONG GROUND MOTION AND TELESEISMIC WAVEFORM DATA FOR THE FAULT RUPTURE HISTORY OF THE 1979 IMPERIAL VALLEY, CALIFORNIA, EARTHQUAKE  

Microsoft Academic Search

A least-squares point-by-point inversion of strong ground motion and tele- seismic body waves is used to infer the fault rupture history of the 1979 Imperial Valley, California, earthquake. The Imperial fault is represented by a plane embedded in a half-space where the elastic properties vary with depth. The inversion yields both the spatial and temporal variations in dislocation on the

STEPHEN H. HARTZELL; THOMAS H. HEATON

1983-01-01

287

Rupture process and strong ground motions of the 2007 Niigataken Chuetsu-Oki earthquake Directivity pulses striking the Kashiwazaki-Kariwa Nuclear Power Plant  

Microsoft Academic Search

The Niigataken Chuetsu-Oki earthquake occurred on July 16, 2007, northwest-off Kashiwazaki in Niigata Prefecture, Japan, causing severe damages of ten people dead, about 1300 injured, about 1000 collapsed houses and major lifelines suspended. In particular, strong ground motions from the earthquake struck the Kashiwazaki-Kariwa nuclear power plant (hereafter KKNPP), triggering a fire at an electric transformer and other problems such

K. Irikura; T. Kagawa; K. Miyakoshi; S. Kurahashi

2007-01-01

288

Source Model of the 2002 Miyagi-Oki Interplate Earthquake (Mw=6.4) Obtained by Strong Ground Motion Simulation Using Empirical Green's Function Method  

NASA Astrophysics Data System (ADS)

Previous studies show that strong motion records of crustal earthquakes can be successfully simulated using aftershock record as empirical Green's function with rectangular source model which is smaller than total fault size estimated from aftershock distribution. We call the area strong motion generation area (SMGA). It is also revealed that the SMGA corresponds to the asperity deduced by kinematic waveform inversion, and its size can be expected from scaling relation between the size of the asperity and the seismic moment. Asano et al. (2003) analyzed shallow intraslab earthquakes in the similar manner and derived that the size of SMGA is smaller than that expected for crustal earthquake of the same seismic moment, and the ratio of the derived and the expected sizes decreases with focal depth. This may implies that the deeper earthquake has the larger stress drop on the asperity. In November 3, 2002, an earthquake of Mw=6.4 (depth was about 45km) occurred in Miyagi-Oki region, north east of Japan, where high percentage of occurrence of interplate events is expected by the long term forecast. This event was thought to be interplate earthquake from moment tensor solution and aftershock distribution. We simulate broadband strong motion records of this interplate earthquake using empirical Green's function method proposed by Irikura (1986). Comparing observed and simulated waveforms, we derive the size and location of the SMGA by forward modeling. The obtained size of the SMGA is smaller than that expected from the relationship between the size and the seismic moment for crustal earthquakes, and is consistent with the relation among the size and the seismic moment and the depth derived from Asano et al. (2003). This result supports the idea that stress drop on the asperity mainly depend on its depth. We would like to thank K-NET and KiK-net for providing strong motion data, F-net for moment tensor solution, and JMA for information of hypocenter.

Suzuki, W.; Iwata, T.

2003-12-01

289

Strong ground motion data from the 1983 Borah Peak, Idaho earthquake recorded at the Idaho National Engineering Laboratory  

SciTech Connect

The 1983 Borah Peak, Idaho Earthquake was the largest normal faulting event to occur in the last 20 years. There were no near-field recordings of ground motion during the main shock, however, thirteen accelerographs in a permanent array at the Idaho National Engineering Laboratory (INEL) recorded the event at epicentral distances of 90 to 110 km. Peak horizontal accelerations (PGA) recorded at accelerographs above ground-floor level range from 0.037 to 0.187 g. Accelerographs at basement and free-field sites recorded as low as 0.022 g and as high as 0.078 g. Peak vertical accelerations range from 0.016 g at ground level to 0.059 g above ground floor level. A temporary array of digital seismographs deployed by the US Geological Survey (USGS) in the epicentral area recorded ground motion from six large aftershocks at epicentral distances of 4 to 45 km; the largest of these aftershocks also triggered four accelerographs in the INEL array. Two separate analyses were used to estimate near-field ground motion. The first analysis uses the attenuation of the aftershock PGA measurements to extrapolate the INEL main shock PGA measurements into the near-field. This estimates an upper limit of 0.8 g for near-field ground motion. In the second analysis, a set of main shock accelerograms were synthesized. Wave propagation effects were determined from aftershock recordings at one of the USGS portable stations and an INEL seismograph station. These effects were removed from one of the INEL main shock acceleration traces. The synthetic accelerograms were derived for a hypothetical station southwest of Mackay, Idaho. The PGA measured from the synthetic accelerograms were 0.08, 0.14, 0.15, 0.23 g. These estimates correlate well with ground motion expected for an area of Intensity VII.

Jackson, S.M.; Boatwright, J.

1985-01-01

290

Field survey around strong motion stations and its implications on the seismic intensity in the Lushan earthquake on April 20, 2013  

NASA Astrophysics Data System (ADS)

The M s7.0 Lushan earthquake on April 20, 2013 is another destructive event in China since the M s8.0 Wenchuan earthquake in 2008 and M s7.1 Yushu earthquake in 2010. A large number of strong motion recordings were accumulated by the National Strong Motion Observation Network System of China. The maximum peak ground acceleration (PGA) at Station 51BXD in Baoxing Country is recorded as -1,005.3 cm/s2, which is even larger than the maximum one in the Wenchuan earthquake. A field survey around three typical strong motion stations confirms that the earthquake damage is consistent with the issued map of macroseismic intensity. For the oscillation period 0.3-1.0 s which is the common natural period range of the Chinese civil building, a comparison shows that the observed response spectrums are considerably smaller than the designed values in the Chinese code and this could be one of the reasons that the macroseismic intensity is lower than what we expected despite the high amplitude of PGAs. The Housner spectral intensities from 16 stations are also basically correlated with their macroseismic intensities, and the empirical distribution of spectral intensities from Lushan and Wenchuan Earthquakes under the Chinese scale is almost identical with those under the European scale.

Ren, Yefei; Ji, Kun; Wen, Ruizhi; Huang, Xutao

2013-08-01

291

Predicting strong motion parameters for the Chamoli earthquake of 28th March, 1999, Garhwal Himalaya, India, from simplified finite fault model  

NASA Astrophysics Data System (ADS)

State of Uttaranchal in the northern part of India in the Garhwal Himalaya was hit by the Chamoli earthquake on 28th March, 1999 (GMT). This earthquake was recorded on a strong motion array installed in this region. The maximum peak ground acceleration of 353 cm/sec2 was recorded at an accelerograph located at the Gopeshwar station at an approximate epicentral distance of 14 km. The simplified method of Midorikawa (1993) has been used to model finite fault responsible for causing the Chamoli earthquake. This method is based on the Empirical Green's Function (EGF) technique of Irikura (1986).Modifications in this method have been made to include layered earth model and transmission effects at each boundary by Joshi (2001). Rupture causing the Chamoli earthquake is placed in two structural models of the earth in this work: one is a homogeneous half space and other is the multi layered earth model. Comparison in terms of root mean square error (RMSE) is made between the simulated and actual strong motion parameters like peak acceleration and duration. It is seen that the introduction of multi layered earth system in this simplified technique is capable of significantly reducing the RMSE in observed and predicted strong motion parameters and defining the attenuation rate for peak ground acceleration of this earthquake.

Joshi, A.

292

Strong ground motion simulation for the Mw6.6 Lushan Earthquake, Sichuan, China, base on the inverted and synthetic slip models  

NASA Astrophysics Data System (ADS)

As we know, the estimation of slip distributions on the fault surface is one of the most important issues for the source inversion of earthquake fault rupturing process. The characteristics of slip distribution on the mainfault play an important role to control strong ground motion pattern. Wang et al., and Zhang et al., published the fast inversion for the rupturing process soon after the 20 April 2013 Lushan, Ya'an earthquake in Sichuan, China. A large amount of works has suggested that variable slip models derived from longer-period ground motion recording are relevant for the prediction of higher-frequency ground motions. The k square model and crack model are well known to describe the slip distribution on the rupture surface. In this study, first we synthesize two forward models: the value of maximum slip, fault dimension, corner wave number derived from Wang model is used to constrain the production of k square model; also, the value of maximum slip, the dimension of asperities from Wang model is used to produce the crack model. Calculation shows that the value of corner wave number of these two synthetic slip models and the inverted models are much the same, and these four slip models are then used to simulate the ground motions for the Lushan earthquake base on the stochastic finite-fault method. Furthermore, a stochastic slip model is also employed for the simulation of strong ground motion for the Lushan event. The simulated results characterized by PGA and PGV show that the source models base on the inverted and synthetic slip distributions could capture most of the basic features of the ground motion. Moreover, the simulated MMI distributions reflect the obvious rupture directivity effect and the influence of the shallow velocity structure well. While the simulation of stochastic slip model is apparently higher than observed MMI. In addition, our simulation result shows that the higher-frequency ground is strongly sensitive to the degree of slip roughness, therefore, we suggest that, for a realistic ground motion simulations due to future earthquake, it is imperative to properly estimate the slip roughness distribution.

Shen, W.; Zhong, Q.; Shi, B.

2013-12-01

293

Comparing Action Gestures and Classifier Verbs of Motion: Evidence from Australian Sign Language, Taiwan Sign Language, and Nonsigners' Gestures without Speech  

ERIC Educational Resources Information Center

Recent research into signed languages indicates that signs may share some properties with gesture, especially in the use of space in classifier constructions. A prediction of this proposal is that there will be similarities in the representation of motion events by sign-naive gesturers and by native signers of unrelated signed languages. This…

Schembri, Adam; Jones, Caroline; Burnham, Denis

2005-01-01

294

Improvement of earthquake locations with the Marine Cable Hosted Observatory (MACHO) offshore NE Taiwan  

NASA Astrophysics Data System (ADS)

In order to improve the locating capability for offshore earthquakes and tsunamis monitored off northeastern Taiwan, a cable-based ocean bottom seismographic observatory named "Marine Cable Hosted Observatory" (MACHO) was constructed and began operation at the end of 2011. The installed instruments of the observatory include a broadband seismometer, a strong-motion seismometer and a pressure gauge. In addition, various scientific instruments could be deployed for other purposes as well. At present, the seismic data are transmitted in real-time via a fiber cable, and integrated into the current inland seismographic network in Taiwan. The ocean bottom station has contributed to provide high quality seismic data already. According to observations from January 2012 to June 2013, there were a total of 15,168 earthquakes recorded by the system. By using the data from the ocean bottom station, the number of relocated earthquakes with an azimuth gap less than 180 degrees substantially increase about 34 %. Meanwhile, the root-mean-square of the time residual, the error in epicenter, and the error in depth of the earthquake locations decrease. Therefore, the implementation of MACHO has the advantage of extending the coverage of existing the Taiwan seismic network to the offshore, providing more accurate and real-time seismic data for offshore earthquakes monitoring. The results show that MACHO is crucial and necessary for monitoring seismic activities in northeastern Taiwan.

Hsiao, Nai-Chi; Lin, Tzu-Wei; Hsu, Shu-Kun; Kuo, Kai-Wei; Shin, Tzay-Chyn; Leu, Peih-Lin

2014-09-01

295

Basement Imaging Using Sp Converted Phases in Chia-Nan, Taiwan  

NASA Astrophysics Data System (ADS)

The Chia-Nan Plain is a long and narrow alluvial plain, located in the west of Central Mountain Range and the east of Taiwan Strait. We used accelerograms recorded from 1992 to 2010 March by the Taiwan Strong Motion Instrumentation Program (TSMIP) stations to study the thickness variations of the Quaternary alluviums beneath the Chia-Nan Plain, the biggest alluvial plain in Taiwan, by examining a Sp converted phase. The thicknesses are estimated by the travel-time difference of S and Sp waves. This technique of using P-S converted phases had a quite success in the previous study of Lan-Yang Plain. By the high seismic activity and dense of TSMIP stations in this study area, we used this technique to depict the variations of Quaternary sediments thicknesses in Chia-Nan Plain. In general, the thicknesses become thicker toward west. Finally, this approach helps us to discuss the shape of Peikang Basement High in the north of Chia-Nan Plain, which plays an important role in the tectonic changing of Taiwan western foothills.

Wei, J.; Wu, Y.; Chuang, M.; Chang, C.

2010-12-01

296

America's Stake in Taiwan  

Microsoft Academic Search

Taiwan is one of democratic Asia's most impor- tant nations: It has a bigger population than Austra- lia, a larger GDP than Indonesia, and an advanced technology base second only to Japan's. Taiwan is America's eighth largest trading partner and sixth largest agricultural customer. For over a half cen- tury, Taiwan has been one of America's important defense and intelligence

John J. Tkacik

297

Deep Borehole Instrumentation Along San Francisco Bay Bridges: 1996 - 2003 and Strong Ground Motion Systhesis Along the San Francisco/Oakland Bay Bridge  

SciTech Connect

As a result of collaboration between the Berkeley Seismographic Station, Lawrence Livermore National Laboratory, and Caltrans, instrument packages have been placed in bedrock in six boreholes and two surface sites along the San Francisco/Oakland Bay Bridge. Since 1996 over 200 local earthquakes have been recorded. Prior to this study few seismic recording instruments existed in bed-rock in San Francisco Bay. We utilized the data to perform analysis of ground motion variability, wave passage, site response, and up-and down-hole wave propagation along the Bay Bridge. We also synthesized strong ground motion at nine locations along the Bay Bridge. Key to these studies is LLNL's effort to exploit the information available in weak ground motions (generally from earthquakes < M=4.0) to enhance predictions of seismic hazards. We found that Yerba Island has no apparent site response at the surface relative to a borehole site. The horizontal to vertical spectral ratio method best revealed no site response, while the complex signal spectral ratio method had the lowest variance for spectral ratios and best predicted surface recordings when the borehole recording was used as input. Both methods identified resonances at about the same frequencies. Regional attenuation results in a significant loss of high frequencies in both surface and borehole recordings. Records are band limited at near 3 Hz. Therefore a traditional rock outcrop site response, flat to high frequency in displacement, is not available. We applied a methodology to predict and synthesize strong ground motion along the San Francisco/Oakland Bay Bridge from a M=7.25 earthquake along the Hayward fault, about12 km distant. We synthesized for three-components and broad-band (0.0-25.0 Hz) ground motion accelerations, velocities, and displacements. We examined two different possible rupture scenarios, a ''mean'' and ''one standard deviation'' model. We combined the high frequency calculations (Hz > 0.7) based on empirical Green's functions with finite difference calculations for frequencies less than 0.7 Hz. We found that in the near-source region, far-field shear-wave generation and near-field tectonic ground displacements can result in very large long period ground displacements and velocity pulses. Far-field arrivals have the strongest energy in periods of about 2 to 5 s, and near-field arrivals have the strongest energy in periods of about 5 to 10 s. Much of these near-source ground motions would not be observed by conventional strong motion recording systems, which typically are high-pass band limited at 2-5 s periods, and therefore have not been included as standard practice structural input ground motions. For some fault rupture scenarios, the large tectonic displacement pulse would initially drive the bridge with motions parallel to tectonic fault displacement, and before the bridge would start to rebound, the far-field S-wave would arrive and drive the bridge in the opposite direction. This type of multiple long-period modal response can occur in other long period structures such as base-isolated systems and tall buildings.

Hutchings, L; Foxall, W; Kasameyer, P; larsen, S; Hayek, C; Tyler-Turpin, C; Aquilino, J; Long, L

2005-04-22

298

Strong-motion, site-effects and hazard issues in rebuilding Turkey: In light of the 17 August, 1999 earthquake and its aftershocks  

USGS Publications Warehouse

The August 17, 1999 Izmit (Turkey) earthquake (Mw=7.4) will be remembered as one of the largest earthquakes of recent times that affected a large urban environment (U.S. Geological Survey, 1999). The shaking that caused the widespread damage and destruction was recorded only by a handful of accelerographs in the earthquake area operated by different networks. The characteristics of these records show that the recorded peak accelerations, even those from near field stations, are smaller than expected. On the other hand, smaller magnitude aftershocks yielded larger peak accelerations. This is attributed to the sparse networks, which possibly missed recording of larger motions during the main shock. As rebuilding of Turkey starts, strong-motion networks that yield essential data must be enlarged. In addition, attention must be paid to new developments elsewhere, such as earthquake zoning maps, earthquake hazard maps, liquefaction potentials and susceptibility. This paper aims to discuss these issues. Copyright??2000 IAHS.

Celebi, M.; Toprak, S.; Holzer, T.

2000-01-01

299

THE FERRARA ARC THRUST EARTHQUAKES OF MAY-JUNE 2012 (NORTHERN ITALY): STRONG-MOTION AND GEOLOGICAL OBSERVATIONS  

E-print Network

1 THE FERRARA ARC THRUST EARTHQUAKES OF MAY-JUNE 2012 (NORTHERN ITALY): STRONG by an earthquake of magnitude Ml5.8 (lat 44.851 long 11.086), located nearly 12 km WSW-ward of the 20 May Ml5 earthquakes, were released few kilometers westward of the epicentral area of the 20 May event. The aftershocks

Fleskes, Joe

300

Integrated System for Earthquake Early Warning and Quick Response Against Strong Motion - In Case of the Tokyo Metro Company  

NASA Astrophysics Data System (ADS)

In July 2005, an earthquake of M6.0 attacked the Tokyo metropolitan area. This earthquake occurred at 35.5N and 140.2E with about 73km in depth, and the maximum JMA intensity was 5+ corresponding to MMI VIII approximately. This earthquake occurred at north-west of Chiba prefecture and caused a traffic disturbance widely in Tokyo metropolitan area. All the train operation had been stopped for a long time after the earthquake, although a severe damage was not caused even in the area of high intensity. The longest down time for the train operation was more than seven hours. After the earthquake, we proposed a new system for early warning and quick response. Tokyo Metro Company accepted our proposal, and we replaced and built the new early warning/quick response system as followed. The system consists of two seismometer networks. One is the early warning system FREQL network with six seismometers to control or stop the train operation immediately after the earthquake occurrence. And the other is the portable digital seismometer AcCo network distributing 33 seismometers in every about three kilometers mesh to grasp more detailed seismic motion on their service area. The information from both FREQL network and AcCo network are gathered to the operation center and displayed on the individual monitoring system. The monitoring system for AcCo can indicate the integrated information from AcCo and FREQL on the subway network image. The AcCo monitoring system is also installed on the control table for each subway line. At the time of the earthquake, the early warning system detects at first the earthquake immediately and then the 33 local seismometers inform the actual earthquake motion of each site independently and rapidly. This system realized quick response and restart of the train operation because the early warning became faster and checking zone after earthquake was optimized. This updated system is expected to realize quicker response during and after. For the large system as the train operation, it is necessary for the control against the earthquake to equip the system not only to issue the early warning but also to support the quick and rational recovery work after the earthquake.

Sato, T.; Saita, J.; Nakamura, Y.

2007-12-01

301

Estimation of Strong Ground Motion from a Great Earthquake Mw 8.5 in Central Seismic Gap Region, Himalaya (India) Using Empirical Green's Function Technique  

NASA Astrophysics Data System (ADS)

In the present study ground motions for a Mw 8.5 scenario earthquake are estimated at 13 sites in Kumaun-Garhwal region using the empirical Green's function technique. The recordings of 1991 Uttarkashi earthquake of Mw 6.8 at these sites are used as an element earthquake. A heterogeneous source model consisting of two asperities is considered for simulating the ground motions. The entire central seismic gap (CSG) can expect acceleration in excess of 100 cm/s2 with NW portion in excess of 400 cm/s2 and SE between 100 and 200 cm/s2. The central portion can expect peak ground acceleration (PGA) between 200 and 400 cm/s2. It has been observed from simulation of strong ground motion that sites located near the rupture initiation point can expect accelerations in excess of 1 g. In the present analysis, Bhatwari and Uttarkashi can expect ground accelerations in excess of 1 g. The estimates of the PGA are compared with earlier studies in the same region using different methodologies and it was found that the results are comparable. This has put constrains on the expected PGAs in this region. The obtained PGA values can be used in identifying the vulnerable areas in the central Himalaya, thereby facilitating the planning, design and construction of new structures and strengthening of the existing structures in the region.

Sharma, Babita; Chopra, Sumer; Sutar, Anup Kumar; Bansal, B. K.

2013-12-01

302

Rupture history of the 2008 Mw 7.9 Wenchuan, China, earthquake: Evaluation of separate and joint inversions of geodetic, teleseismic, and strong-motion data  

USGS Publications Warehouse

earthquake. A linear multiple-time-window approach is used to parameterize the rupture. Because of the complexity of the Wenchuan faulting, three separate planes are used to represent the rupturing surfaces. This earthquake clearly demonstrates the strengths and limitations of geodetic, teleseismic, and strong-motion data sets. Geodetic data (static offsets) are valuable for determining the distribution of shallower slip but are insensitive to deeper faulting and reveal nothing about the timing of slip. Teleseismic data in the distance range 30°–90° generally involve no modeling difficulties because of simple ray paths and can distinguish shallow from deep slip. Teleseismic data, however, cannot distinguish between different slip scenarios when multiple fault planes are involved because steep takeoff angles lead to ambiguity in timing. Local strong-motion data, on the other hand, are ideal for determining the direction of rupture from directivity but can easily be over modeled with inaccurate Green’s functions, leading to misinterpretation of the slip distribution. We show that all three data sets are required to give an accurate description of the Wenchuan rupture. The moment is estimated to be approximately 1:0×1021 N · m with the slip characterized by multiple large patches with slips up to 10 m. Rupture initiates on the southern end of the Pengguan fault and proceeds unilaterally to the northeast. Upon reaching the cross-cutting Xiaoyudong fault, rupture of the adjacent Beichuan fault starts at this juncture and proceeds bilaterally to the northeast and southwest.

Hartzell, Stephen; Mendoza, Carlos; Ramírez-Guzmán, Leonardo; Zeng, Yuesha; Mooney, Walter

2013-01-01

303

Geometric Brownian Motion Consider the geometric Brownian motion process  

E-print Network

Geometric Brownian Motion · Consider the geometric Brownian motion process Y (t) eX(t) ­ X(t) is a (µ, ) Brownian motion. · As Y/X = Y and 2 Y/X2 = Y , Ito's formula (51) on p. 453 implies dY Y = µ-Dauh Lyuu, National Taiwan University Page 459 Product of Geometric Brownian Motion Processes · Let d

Lyuu, Yuh-Dauh

304

Rupture process and wave radiation characteristics of the 2011 Tohoku-Oki mega-thrust earthquake examined using the strong-motion data  

NASA Astrophysics Data System (ADS)

The 2011 Tohoku-Oki earthquake is the first M9 earthquake that has been recorded by the dense strong-motion networks in the near-fault region. The strong-motion waveforms obtained by the two nation-wide networks, K-NET and KiK-net operated by the National Research Institute for Earth Science and Disaster Prevention (Aoi et al., 2011, Kunugi et al., 2011, this meeting), can provide the detailed information about the source of the mega-thrust earthquake. As a first step to elucidating the generation mechanism of this devastating earthquake that caused the severe ground shaking and catastrophic tsunami, we derive the rupture process using the relatively low-frequency (0.01-0.125 Hz) strong-motion data. We performed the multi-time-window linear waveform inversion analysis. The derived slip model has one prominent large slip area extending from the area around the hypocenter to the shallow part of the fault plane along the trench axis. This shallow large slip area is located far off southern Iwate, Miyagi, and northern Fukushima prefectures, where the tsunami damage was huge. The rupture of this area started 60 s after the initial break with a long duration of 40 s. This rupture event radiated the seismic waves rich in very low-frequency content. The deep portion of the fault between the hypocenter and the coast of Miyagi prefecture experienced the two down-dip rupture events in 20-50 s and 60-100 s, which largely contributed to the waveform synthesis at the stations to the west of the central part of the fault plane although the slip there is relatively small compared to the shallow slip area along the trench axis. Particularly, the second rupture event makes a significant contribution to the phase with largest amplitude. The shallow large slip also contributes to this largest amplitude phase. The former and latter make contribution in relatively high and low frequency ranges, respectively. Rupture after 100 s propagated in the southern part of the fault and generated the distinct phase observed in the southern stations. We also examine the frequency dependency of the wave radiation process considering the features of the observed acceleration waveforms.

Suzuki, W.; Aoi, S.; Sekiguchi, H.; Kunugi, T.

2011-12-01

305

Focal-Mechanism Determination in Taiwan by Genetic Algorithm  

Microsoft Academic Search

Abstract We determined the focal-mechanism solutions for earthquakes with mag- nitude ML ?4:0 that occurred in the Taiwan region between,1991 and 2005. First- motion polarities of P waves recorded at over 700 seismic stations in Taiwan were used. Because of the large number of events and stations involved, we implemented the genetic algorithm in a nonlinear global search for the

Y.-M. Wu; L. Zhao; C.-H. Chang; Y.-J. Hsu

2008-01-01

306

Surface-wave site characterization at 53 strong-motion recording stations affected by the Parkfield, California, M6.0 earthquake of 28 September 2004  

USGS Publications Warehouse

We present one-dimensional shear-wave velocity (VS) profiles at 52 strong-motion sites that recorded the 28 September 2004 Magnitude 6.0 Parkfield, Calif., earthquake. We estimate the VS profiles with the Spectral Analysis of Surface-Waves (SASW) method. The SASW method is a noninvasive method that indirectly estimates the VS at depth from variations in the Rayleigh wave phase velocity at the surface. To address the uncertainty associated with these measurements, we compare the SASW profiles to surface-source downhole-receiver (SSDR) profiles at four sites. Three of the four SSDR sites are in close agreement with the adjacent SASW site, while the SASW profile is considerably slower than the SSDR profile at one site.

Thompson, Eric M.; Kayen, Robert E.; Carkin, Brad; Tanaka, Hajime

2010-01-01

307

K-NET and KiK-net strong-motion data of the 2011 Tohoku-Oki earthquake (M9.0)  

NASA Astrophysics Data System (ADS)

The 11 March 2011 Tohoku-Oki earthquake is the largest instrumentally recorded earthquake in Japan to date (M9.0, JMA). The vibration from this devastating earthquake was felt almost all over Japan and severe shaking of JMA seismic intensity of "6 lower" or higher was recorded from Kanto to Tohoku districts, in East Japan. The earthquake generated a huge tsunami, which caused catastrophic damages to the Pacific coast of the Honshu Island, particularly to Iwate, Miyagi, and Fukushima prefectures. The National Research Institute for Earth Science and Disaster Prevention (NIED) operates two nation-wide strong-motion observation networks K-NET and KiK-net, which succeeded in recording the strong-motion accelerograms at more than one thousand stations almost all over Japan. The earthquake and the associated tsunami directly affected facilities and operation of K-NET and KiK-net. The tsunami damaged 5 stations in Iwate and Miyagi prefectures. The data center of K-NET and KiK-net in Tsukuba, Ibaraki prefecture was also damaged by the strong motion of main shock and major aftershocks, and a blackout lasted for almost 1 day. Tens of communication lines of stations were not available immediately after the earthquake. Some of them had not been available during several weeks or months. In the noon of March 12, electric power of the data center was restored. After a stable electric power supply was secured, we restarted the data center system operations, and subsequently started to retrieve records from the stations. On March 15 we released the first version of K-NET and KiK-net data set of the main shock on our web sites. The data set consisted of accelerograms from 388 stations. We updated the data set three times as retrieval of the records progressed. The latest version was published on July 13. That release consisted of accelerograms from 1212 stations including 19 stations where peak ground accelerations above 1000 gals were recorded. Although we tried to retrieve records by on-site operations at the stations where wiring was unavailable, records of the 2 stations in Fukushima prefecture have not been yet retrieved because the stations are located in an exclusion zone around the Fukushima Daiichi nuclear power plant. Moreover, we lost records of 2 stations close to the coast in Iwate prefecture, since the stations were completely swept away by the tsunami. In this presentation, we will introduce our response to the emergency situation of data retrieval, publishing data, and system operation of K-NET and KiK-net after the 2011 Tohoku-Oki earthquake. Strong-motion data of K-NET and KiK-net are available on the following web sites (http://www.k-net.bosai.go.jp/, http://www.kik.bosai.go.jp/ )

Kunugi, T.; Suzuki, W.; Aoi, S.; Nakamura, H.; Pulido Hernandez, N. E.; Morikawa, N.; Fujiwara, H.

2011-12-01

308

Rupture history of the 2009 L'Aquila (Italy) earthquake from non-linear joint inversion of strong motion and GPS data  

NASA Astrophysics Data System (ADS)

We image the rupture history of the 2009 L'Aquila (central Italy) earthquake using a nonlinear joint inversion of strong motion and GPS data. This earthquake ruptured a normal fault striking along the Apennines axis and dipping to the SW. The inferred slip distribution is heterogeneous and characterized by a small, shallow slip patch located up-dip from the hypocenter (9.5 km depth) and a large, deeper patch located southeastward. The rupture velocity is larger in the up-dip than in the along-strike direction. This difference can be partially accounted by the crustal structure, which is characterized by a high velocity layer above the hypocenter and a lower velocity below. The latter velocity seems to have affected the along strike propagation since the largest slip patch is located at depths between 9 and 14 km. The imaged slip distribution correlates well with the on-fault aftershock pattern as well as with mapped surface breakages.

Cirella, A.; Piatanesi, A.; Cocco, M.; Tinti, E.; Scognamiglio, L.; Michelini, A.; Lomax, A.; Boschi, E.

2009-10-01

309

Maternity Leave in Taiwan  

ERIC Educational Resources Information Center

Using the first nationally representative birth cohort study in Taiwan, this paper examines the role that maternity leave policy in Taiwan plays in the timing of mothers returning to work after giving birth, as well as the extent to which this timing is linked to the amount of time mothers spend with their children and their use of breast milk…

Feng, Joyce Yen; Han, Wen-Jui

2010-01-01

310

Site Amplification Characteristics and Their Variations Derived from K-NET, KiK-Net, and JMA Strong Motion Records in Japan  

NASA Astrophysics Data System (ADS)

To predict strong ground motions for future scenario earthquake in a broad-band frequency, we need to characterize both source spectra and site amplification. For short period we can use statistical method based on the observed records and the summation technique of observed waveforms or their synthetic substitutes. Thanks to the advent of the nationwide strong motion networks in Japan, we have now plenty of weak motion data, enough to construct statistical Green"fs functions. Since the site amplification effects on the sediment sites in an urbanized environment tend to be so large that we need to extract site amplification ratios in a statistical manner and construct amplification models for different site categories. In this study we perform first the analysis to separate the so-called source spectra, attenuation coefficient, and the site amplification factors from about 18,825 K-NET, KiK-Net, and JMA records observed at more than 1,700 stations in Japan. The separation method is the well-established one of Andrews (1980) and the resultant source spectra are modeled as omega-square spectra. As a reference site we use one rock station of KiK-Net in Yamaguchi Prefecture, from which we remove amplification due to the shallow weathered rock formation. Once we obtain site amplification factors, we try to reproduce them by using one-dimensional S- wave velocity structures below each site of K-NET and KiK-Net (in total, 1,300). We use Genetic Algorithm to invert the S-wave structures with fixed S-wave velocities in the shallow part. We succeed to reproduce site amplification factors at about one half of the sites very well. We then calculate average S-wave velocities for top 30 m, the so-called Vs-30. We also perform the same kind of separation analysis for three ground motion strength indexes, namely, PGA, PGV, and JMA Seismic Intensity. We found that the variations in spectral ratios between observed site amplification and averaged one is about 0.26 in a logarithmic scale, minimum (0.23) at 0.1 Hz and maximum (0.28) at 3 Hz. The variation at 3 Hz is largest probably because the fundamental peak frequency for soft sediments sites will be around 3 Hz so that small deviation in peak frequency for one event may result in relatively large deviation. Averaged spectral ratios for sites with different Vs-30 categories show peak values of about 10 irrespective of the Vs- 30 categories, although their frequencies tend to be higher as Vs-30 become larger. As for the strength indexes, the variation tend to be largest near the source and then monotonically decreasing to the minimum values at around 100 km away from the source. We also found that observed strength indexes tend to be higher in the near-field compared to the predicted values from the separated empirical models. The variations as a function of the strength index levels show quite stable values of around 0.2. However, the log-average ratios between the predicted and the observed (i.e., the prediction error) become minus if PGA becomes larger than 400 Gals or PGV larger than 30 cm/s, due to nonlinear response of soil deposits.

Kawase, H.

2008-12-01

311

Taper Angle Evolution in Taiwan Accretionary Wedge  

NASA Astrophysics Data System (ADS)

Liwen Chena,b, Wu-Cheng Chia, Char-Shine Liuc aInstitute of Earth Sciences, Academia Sinica, Taipei, Taiwan bInstitute of Geosciences, National Taiwan University, Taipei, Taiwan cInstitute of Oceanography, National Taiwan University, Taipei, Taiwan The critical taper model, originally developed using onland Taiwan as an example, is governed by force balance of a horizontal compressional wedge. This model has been successfully applied to many mountainous regions around the world. Among them, Taiwan is located in an oblique collision between the Luzon Arc and the Chinese Passive margin. Previous critical taper angle studies of Taiwan are mainly focusing on utilizing land data. In this study we want to extend these studies to offshore region from the subduction zone to collision zone. Here we study the varying taper angles of the double-vergent wedge derived from 1,000 km of reflection seismic profiles in both the pro-wedge and retro-wedge locations. These profiles were collected in the last two decades. For the retro-wedge, the topography slope angle changes from 2 to 8.8 degrees; some of the steep slope suggests that some part of the retrowedge is currently in a super-critical angle state. Such dramatic changes in taper angle probably strongly affect regional sedimentary processes, including slumping, in addition to structural deformation. These complex processes might even help develop a mélange or re-open a closed basin. We are currently working on studying the taper angle evolution of the pro-wedge from subduction to arc-continent collision zone in the offshore region. Though further works are needed, our preliminary results show that the evolution of wedge angles and the geometry of the wedge are closely linked and inseparable. The structures of the subducting plate might have strong influence on the deformation style of the over-riding plate. It would be interesting to combine the angle variation with the structure interpretation of the accretionary wedge, both in the pro- and retro-wedge regions. And the results might help us to better understand the evolution of Taiwan Accretionary Prism.

Chen, L.; Chi, W.; Liu, C.

2011-12-01

312

Comparison of shear-wave slowness profiles at 10 strong-motion sites from noninvasive SASW measurements and measurements made in boreholes  

USGS Publications Warehouse

The spectral-analysis-of-surface-waves (SASW) method is a relatively new in situ method for determining shear-wave slownesses. All measurements are made on the ground surface, making it much less costly than methods that require boreholes. The SASW method uses a number of active sources (ranging from a commercial Vibroseis truck to a small handheld hammer for the study conducted here) and different receiver spacings to map a curve of apparent phase velocity versus frequency. With the simplifying assumption that the phase velocities correspond to fundamental mode surface waves, forward modeling yields an estimate of the sub-surface shear-wave slownesses. To establish the reliability of this indirect technique, we conducted a blind evaluation of the SASW method. SASW testing was performed at 10 strong-motion stations at which borehole seismic measurements were previously or subsequently made; if previously made, the borehole results were not used for the interpretation of the SASW data, and vice-versa. Comparisons of the shear-wave slownesses from the SASW and borehole measurements are generally very good. The differences in predicted ground-motion amplifications are less than about 15% for most frequencies. In addition, both methods gave the same NEHRP site classification for seven of the sites. For the other three sites the average velocities from the downhole measurements were only 5-13 m/sec larger than the velocity defining the class C/D boundary. This study demonstrates that in many situations the SASW method can provide subsurface information suitable for site response predictions.

Brown, L. T.; Boore, D. M.; Stokoe, II, K. H.

2002-01-01

313

Estimation of the source model for the foreshock of the 2004 off the Kii peninsula earthquakes and strong ground motion simulation of the hypothetical Tonankai earthquake using the empirical Green's function method  

NASA Astrophysics Data System (ADS)

We estimated the source model for the foreshock of the 2004 off the Kii peninsula earthquakes by empirical Green's function modeling. The size and the rise time of the strong motion generation area (SMGA) were estimated to be 30 × 15 km, and 0.9 sec, respectively. The stress drop of the SMGA was calculated to be 8.3 MPa. This model could reproduce long-period ground motions following the direct S-wave observed in the Osaka basin well. Using the derived source parameters, we simulated strong motions of the hypothetical Tonankai earthquake. Distribution of the seismic intensity derived here is similar to that obtained by the previous report. We could predict long-period ground motions which last for a long duration at the basin sites.

Suzuki, Wataru; Iwata, Tomotaka; Asano, Kimiyuki; Yamada, Nobuyuki

2005-04-01

314

A new algorithm for tight integration of real-time GPS and strong-motion records, demonstrated on simulated, experimental, and real seismic data  

NASA Astrophysics Data System (ADS)

The complementary advantages of GPS and seismic measurements are well recognized in seismotectonic monitoring studies. Therefore, integrated processing of the two data streams has been proposed recently in an attempt to obtain accurate and reliable information of surface displacements associated with earthquakes. A hitherto still critical issue in the integrated processing is real-time detection and precise estimation of the transient baseline error in the seismic records. Here, we report on a new approach by introducing the seismic acceleration corrected by baseline errors into the state equation system. The correction is performed and regularly updated in short epochs (with increments which may be as short as seconds), so that station position, velocity, and acceleration can be constrained very tightly and baseline error can be estimated as a random-walk process. With the adapted state equation system, our study highlights the use of a new approach developed for integrated processing of GPS and seismic data by means of sequential least-squares adjustment. The efficiency of our approach is demonstrated and validated using simulated, experimental, and real datasets. The latter were collected at collocated GPS and seismic stations around the 4 April 2010, E1 Mayor-Cucapah earthquake (Mw, 7.2). The results have shown that baseline errors of the strong-motion sensors are corrected precisely and high-precision seismic displacements are real-timely obtained by the new approach.

Tu, Rui; Ge, Maorong; Wang, Rongjiang; Walter, Thomas R.

2014-01-01

315

Investigating source directivity for the 2012 Ml5.9 Emilia (Northern Italy) earthquake by jointly using High-rate GPS and Strong motion data  

NASA Astrophysics Data System (ADS)

On May, 20th 2012, the Ferrara and Modena provinces (Emilia Romagna, Northern Italy) were struck by a moderate magnitude earthquake (Ml 5.9). The focal mechanism is consistent with a ~E-W-striking thrust fault. The mainshock was recorded by 29 high-rate sampling (1-Hz) continuous GPS (HRGPS) stations belonging to scientific or commercial networks and by 55 strong motion (SM) stations belonging to INGV (Istituto Nazionale di Geofisica e Vulcanologia) and RAN (Rete Accelerometrica Nazionale) networks, respectively. The spatial distribution of both HRGPS and SM stations with respect to the mainshock location allows a satisfactory azimuthal coverage of the area. To investigate directivity effects during the mainshock occurrence, we analyze the spatial variation of the peak ground displacement (PGD) measured either for HRGPS or SM sites, using different methods. For each HRGPS and SM site, we rotated the horizontal time series to the azimuth direction and we estimated the GPS-related and the SM-related peak ground displacement (G-PGD and S-PGD, respectively) retrieved by transverse component. However, in contrast to GPS displacements, the double integration of the SM data can be affected by the presence of drifts and, thus, they have to be corrected by quasi-manual procedures. To more properly compare the G-PGDs to the S-PGDs, we used the response spectrum. A response spectrum is simply the response of a series of oscillators of varying natural frequency, that are forced into motion by the same input. The asymptotic value of the displacement response spectrum is the peak ground displacement. Thus, for each HRGPS and SM site, we computed the value of this asymptotic trend (G-PGDrs and S-PGDrs, respectively). This method allows simple automatic procedures. The consistency of the PGDs derived from HRGPS and SM is also evaluated for sites where the two instruments are collocated. The PGDs obtained by the two different methods and the two different data types suggest a source directivity effect in the SE (~120°-150°N) direction.

Avallone, A.; Herrero, A.; Latorre, D.; Rovelli, A.; D'Anastasio, E.

2012-12-01

316

Time Dependent Fluid Occurrence Offshore Taiwan  

NASA Astrophysics Data System (ADS)

Time Dependent Fluid Occurrence Offshore Taiwan Liwen Chenab, Wu-Cheng Chia, Char-Shine Liuc (mma@earth.sinica.edu.tw)(wchi@gate.sinica.edu.tw) ; aInstitute of Earth Sciences, Academia Sinica, Taipei, Taiwan bInstitute of Geosciences, National Taiwan University, Taipei, Taiwan ; cInstitute of Oceanography, National Taiwan University, Taipei, Taiwan Earthquake-induced groundwater flows have been observed recently. Such fluid flow might temporarily change the temperature field in the crust. Here we used seismically detected gas hydrate under seafloor to study the temperature fields at a few hundred meters subbottom depth before, and after the 2006 Henchuan earthquake (Mw7.0). We used the hydrate-related bottom-simulating-reflector (BSR) in seismic profiles to study the effects of gas/fluid migration on the BSR attributes. We have conducted two seismic experiments before and after the earthquake across the same transects near the hypocenter of the earthquake using similar air gun arrays and streamers. By analyzing this unique dataset, we found enhanced BSR reflectivity in average after the earthquake (~0.03), but the Sea-floor reflectivity is very similar (~0.5). We also found changed amplitudes versus offset (AVO) in the dataset (the gradient of reflection coefficient versus the angles was ~-0.34). We interpret these results as a consequence of earthquake-induced gas and fluid migration, bringing the gases underneath the BSR, thus the enhanced reflection coefficients. Next we will explore new methods to use the BSR as a flow meter. Using time-dependent seismic attribute analyses across transects before and after a large earthquake, we found strong evidences of earthquake-related fluid migrations and possibly associated temperature perturbations. This is among the first studies to document such feature in the offshore region.

Chen, L.

2010-12-01

317

ARRA-funded VS30 measurements using multi-technique approach at strong-motion stations in California and central-eastern United States  

USGS Publications Warehouse

Funded by the 2009 American Recovery and Reinvestment Act (ARRA), we conducted geophysical site characterizations at 191 strong-motion stations: 187 in California and 4 in the Central-Eastern United States (CEUS). The geophysical methods used at each site included passive and active surface-wave and body-wave techniques. Multiple techniques were used at most sites, with the goal of robustly determining VS (shear-wave velocity) profiles and VS30 (the time-averaged shear-wave velocity in the upper 30 meters depth). These techniques included: horizontal-to-vertical spectral ratio (HVSR), two-dimensional (2-D) array microtremor (AM), refraction microtremor (ReMi™), spectral analysis of surface wave (SASW), multi-channel analysis of surface waves (Rayleigh wave: MASRW; and Love wave: MASLW), and compressional- and shear-wave refraction. Of the selected sites, 47 percent have crystalline, volcanic, or sedimentary rock at the surface or at relatively shallow depth, and 53 percent are of Quaternary sediments located in either rural or urban environments. Calculated values of VS30 span almost the full range of the National Earthquake Hazards Reduction Program (NEHRP) Site Classes, from D (stiff soils) to B (rock). The NEHRP Site Classes based on VS30 range from being consistent with the Class expected from analysis of surficial geology, to being one or two Site Classes below expected. In a few cases where differences between the observed and expected Site Class occurred, it was the consequence of inaccurate or coarse geologic mapping, as well as considerable degradation of the near-surface rock. Additionally, several sites mapped as rock have Site Class D (stiff soil) velocities, which is due to the extensive weathering of the surficial rock.

Yong, Alan; Martin, Antony; Stokoe, Kenneth; Diehl, John

2013-01-01

318

Rupture process of the 2011 Tohoku-Oki mega-thrust earthquake (M9.0) inverted from strong-motion data  

NASA Astrophysics Data System (ADS)

We investigate the rupture process of the M9.0 Tohoku-Oki mega-thrust earthquake using the relatively low-frequency strong-motion records (0.01-0.125 Hz) observed at 36 K-NET and KiK-net stations, the epicentral distances of which range from 120 km to 400 km. The fault model is a rectangular plane, the length and width of which are 510 km along the Japan Trench and 210 km along subducting direction of the Pacific Plate, respectively. We perform the multi-time-window inversion analysis with a 30 × 30 km2 subfault. The derived slip model has one large slip area. This area extends from the region around the hypocenter to the shallow part of the fault plane and further to the north and south along the trench axis, located far off southern Iwate, Miyagi, and northern Fukushima prefectures. The seismic moment is 4.42 × 1022 Nm (Mw 9.0) and the maximum slip is 48 m. The slips near the coast are relatively small, except off Miyagi prefecture, which experienced a slip greater than 5 m. The shallow large slip area, which continuously ruptured from 60 s to 100 s after the initial break, radiated seismic waves rich in very-low-frequency content (<0.02 Hz). The rupture after 100 s propagating to the southern fault area, contributes to the distinct phases observed for Fukushima and Ibaraki prefectures. The relationship between the proposed rupture model and the feature of the acceleration waveforms is not straightforward and suggests the frequency dependency of the seismic wave radiation.

Suzuki, Wataru; Aoi, Shin; Sekiguchi, Haruko; Kunugi, Takashi

2011-10-01

319

A physically based strong ground-motion prediction methodology; application to PSHA and the 1999 Mw = 6.0 Athens earthquake  

Microsoft Academic Search

We present a physically based methodology to predict the range of ground-motion hazard for earthquakes along specific faults or within specific source volumes, and we demonstrate how to incorporate this methodology into probabilistic seismic hazard analyses (PSHA). By `physically based,' we refer to ground-motion syntheses derived from physics and an understanding of the earthquake process. This approach replaces the aleatory

Lawrence Hutchings; Eleni Ioannidou; William Foxall; Nicholas Voulgaris; Jean Savy; Ioannis Kalogeras; Laura Scognamiglio; George Stavrakakis

2007-01-01

320

High-rate GPS seismology for the 2013 ML 6.4 Wanrung, Taiwan earthquake  

NASA Astrophysics Data System (ADS)

The 31 October 2013 ML 6.4 Wanrung earthquake was well recorded by twenty-five 1-Hz and sixteen 10-Hz GPS receivers and twenty-five seismometers located within the epicentral distance of about 80 km. Precise Point Positioning kinematic solutions estimated by software VADASE, RTKLIB, and GIPSY are used to obtain the co-seismic deformations and dynamic displacements. We used seismograms recorded by broadband seismometers and strong motion accelerometers to verify the capability of high-rate GPS for the detections of the body waves and surface waves generated by a moderate-size earthquake. Results show that the overall standard deviations of the position time series are ~6 mm and ~20 mm in the horizontal and vertical components, respectively after applying spatial filtering. Largest co-seismic displacement derived from high-rate GPS is nearly twenty centimeter at 5 km northeast of the epicenter. S waves and surface waves are successfully detected by motions of 10-Hz GPS and double-integrated accelerometers within the 15 km epicentral distance. We also found that a group of later phases of ~1-2.5 cm peak-to-peak amplitudes with a frequency range of 0.2-0.5 Hz located within the Longitudinal Valley, a suture zone composed of Holocene thick sediment deposits. The 2013 Wanrung, Taiwan earthquake recorded by the high-rate GPS network in Taiwan demonstrates the feasibility of GPS Seismology for a moderate size earthquake at a local scale.

Hung, Huang-Kai; Rau, Ruey-Juin; Colosimo, Gabriele; Benedetti, Elisa; Branzanti, Mara; Crespi, Mattia; Mazzoni, Augusto

2014-05-01

321

ISET Journal of Earthquake Technology, Paper No. 468, Vol. 43, No. 1-2, March-June 2006, pp. 11-29 ANALYSIS OF STRONG MOTION DATA OF THE UTTARKASHI  

E-print Network

ISET Journal of Earthquake Technology, Paper No. 468, Vol. 43, No. 1-2, March-June 2006, pp. 11-29 ANALYSIS OF STRONG MOTION DATA OF THE UTTARKASHI EARTHQUAKE OF 20TH OCTOBER 1991 AND THE CHAMOLI EARTHQUAKE of two major earthquakes in the Garhwal Himalayas, namely the 1991 Uttarkashi Earthquake and the 1999

Gupta, Vinay Kumar

322

B values and ??-?? seismic source models: Implications for tectonic stress variations along active crustal fault zones and the estimation of high-frequency strong ground motion  

USGS Publications Warehouse

In this study the tectonic stress along active crustal fault zones is taken to be of the form ??(y) + ????p(x, y), where ??(y) is the average tectonic stress at depth y and ???? p(x, y) is a seismologically observable, essentially random function of both fault plane coordinates; the stress differences arising in the course of crustal faulting are derived from ????p(x, y). Empirically known frequency of occurrence statistics, moment-magnitude relationships, and the constancy of earthquake stress drops may be used to infer that the number of earthquakes N of dimension ???r is of the form N ?? 1/r2 and that the spectral composition of ????p(x, y) is of the form |????p(k)| ?? l/k2, where ????p(k) is the two-dimensional Fourier transform of ????p(x, y) expressed in radial wave number k. The y = 2 model of the far-field shear wave displacement spectrum is consistent with the spectral composition |????p(K)| ?? l/k2, provided that the number of contributions to the spectral representation of the radiated field at frequency f goes as (k/ko), consistent with the quasi-static frequency of occurrence relation N ?? 1/r2; K o is a reference wave number associated with the reciprocal source dimension. Separately, a variety of seismologic observations suggests that the ?? = 2 model is the one generally, although certainly not always, applicable to the high-frequency spectral decay of the far-field radiation of earthquakes. In this framework, then, b values near 1, the general validity of the y = 2 model, and the constancy of earthquake stress drops independent of size are all related to the average spectral composition of ???? p(x, y), |????p(k)| ?? l/k2. Should one of these change as a result of premonitory effects leading to failure, as has been specifically proposed for b values, it seems likely that one or all of the other characteristics will change as well from their normative values. Irrespective of these associations, the far-field, high-frequency shear radiation for the y = 2 model in the presence of anelastic attenuation may be interpreted as band-limited, finite duration white noise in acceleration. Its rms value, arms, is given by the expression arme = 0.85[21/2(2??)2/106] (????/pR)(f max/f0)1/2, where ???? is the earthquake stress drop, p is density, R is hypocentral distance, fo is the spectral corner frequency, and fmax is determined by R and specific attenuation 1/Q. For several reasons, one of which is that it may be estimated in the absence of empirically defined ground motion correlations, a rms holds considerable promise as a measure of high-frequency strong ground motion for engineering purposes. Copyright ?? 1979 by the American Geophysical Union.

Hanks, T. C.

1979-01-01

323

Image-based motion blur for stop motion animation  

Microsoft Academic Search

Stop motion animation is a well-established technique where still pictures of static scenes are taken and then played at film speeds to show motion. A major limitation of this method appears when fast motions are desired; most motion appears to have sharp edges and there is no visible motion blur. Appearance of motion blur is a strong perceptual cue, which

Gabriel J. Brostow; Irfan A. Essa

2001-01-01

324

Rock mass response to strong ground motion generated by mining induced seismic events and blasting observed at the surface of the excavations in deep level gold mines in South Africa  

NASA Astrophysics Data System (ADS)

The strong ground motion generated by mining induced seismic events was studied to characterize the rock mass response and to estimate the site effect on the surface of the underground excavations. A stand-alone instruments, especially designed for recording strong ground motions, were installed underground at a number of deep level gold mines in South Africa. The instruments were recording data at the surface of the stope hangingwalls. A maximum value of 3 m/s was measured. Therefore data were compared to the data recorded in the solid rock by the mine seismic networks to determine the site response. The site response was defined as the ratio of the peak ground velocity measured at the surface of the excavations to the peak ground velocity inferred from the mine seismic data measured in the solid rocks. The site response measured at all mines studied was found to be 9 ± 3 times larger on average. A number of simulated rockbursts were conducted underground in order to estimate the rock mass response when subjected to extreme ground motion and derive the attenuation factors in near field. The rockbursts were simulated by means of large blasts detonated in solid rock close to the sidewall of a tunnel. The numerical models used in the design of the simulated rockbursts were calibrated by small blasts taking place at each experimental site. A dense array of shock type accelerometers was installed along the blasting wall to monitor the attenuation of the strong ground motion as a function of the distance from the source. The attenuation of the ground motion was found to be proportional to the distance from the source following R^-1.1 & R^-1.7 for compact rock and R^-3.1 & R^-3.4 for more fractured rock close to the surface of the tunnel. In addition the ground motion was compared to the quasi-static deformations taking place around the underground excavations. The quasi-static deformations were measured by means of strain, tilt and closure. A good correspondence between the quasi-static deformations and seismic ground motion was found. During the blasting time and the subsequent seismic events the strain, tilt and closure show a rapid increase. Similar increase was observed during the strong seismic event. The deformations associated with a strong seismic event were described as 'fast' seismic events. Much of quasi-static deformations, however, occurred independently of the seismic events and was described as 'slow' or aseismic events.

Milev, Alexander; Durrheim, Ray; Ogasawara, Hiroshi

2014-05-01

325

Preliminary study on soil to rock spectral ratio method of microtremor measurement in Taipei Basin, Taiwan  

NASA Astrophysics Data System (ADS)

Taipei city is the capital of Taiwan which located in Taipei basin and covered with hundreds meter of alluvial layer that might cause serious damage during huge earthquake. Prediction of possible strong motion levels occurred in the basin then became popular. Engineers most like to use Ground Motion Prediction Equation (GMPEs) as common tool for seismic hazard calculation but GMPEs were usually debated that it can only give one prediction value (PGA, PGV, Sa etc.) rather than time history or spectrum. Seismologists tried theoretical simulation (1D, 2D, 3D method) but could only give low frequency (usually less than 1 Hz) results restricted to that the shallow structures were not clear enough. Resent years, wide frequency simulation techniques such as empirical green's function added stochastic simulation method (hybrid method) were applied to several different purposes but site effect still plays an important role that need to be considered. Traditionally soil to rock spectral ratio of shear wave (denoted as S/R) was widely applied to check basin effect for decades but the technique needs lots of permanent stations and several years to get enough records. If some site located within strong motion network but not close enough to the strong motion stations, interpolate or extrapolate results needed to be used. Wen and Huang (2012) conducted a dense microtremor measurement network in whole Taiwan and applied microtremor H/V to discuss dominant frequency with traditional transfer functions from earthquake shear wave and found good agreement between them. Furthermore, in this study, the ability of soil to rock spectral ratio of microtremor (denoted as MS/R) measurement was tested in Taipei basin. The preliminary results showed MS/R had good agreement with S/R between 0.2 to 5 Hz. And distance from soil site to reference rock site should no greater than 8 to 10 km base on degree of spectrum difference (DSPD) calculation. If the MS/R works that site effect study from this technique could be applied for some region which distribution of strong motion stations were not dense enough after all.

Huang, Jyun Yan; Wen, Kuo Liang; Te Chen, Chun; Chang, Shun Chiang

2014-05-01

326

BROWNIAN MOTION MAXWELL STOLARSKI  

E-print Network

BROWNIAN MOTION MAXWELL STOLARSKI Abstract. This paper introduces Brownian motion and covers several in- variances of Brownian motion, some of which follow from the definition and another which follows from the strong Markov property of Brownian motion. We go on to show the nondifferentiability

May, J. Peter

327

New Taiwan macrolichens  

Microsoft Academic Search

[New to Taiwan: Baeomyces rufus, Candelaria concolor, Cladonia glauca, C. incrassata, C. phyllopoda, C. strepsilis, C. subsquamosa, C. umbricola, Dibaeis baeomyces, D. pulogensis, D. sorediata, Dirinaria aegialita, D. confluens, Ephebe lanata, Heterodermia microphylla, H. verrucifera, Hyperphyscia adglutinata, H. cochlearis, H. granulata, Hypotrachyna rockii, Leioderma sorediatum, Leptogium austroamericanum, L. burnetiae, L. corticola, L. denticulatum, L. laceroides, L. marginellum, L. phyllocarpum, L.

A Aptroot; L B Sparrius; M-J Lai

2002-01-01

328

Strong Ground Motion Simulation and Source Modeling of the April 1, 2006 Tai-Tung Earthquake Using Empirical Green's Function Method  

NASA Astrophysics Data System (ADS)

The Tai-Tung earthquake (ML=6.2) occurred at the southeastern part of Taiwan on April 1, 2006. We examine the source model of this event using the observed seismograms by CWBSN at five stations surrounding the source area. An objective estimation method was used to obtain the parameters N and C which are needed for the empirical Green’s function method by Irikura (1986). This method is called “source spectral ratio fitting method” which gives estimate of seismic moment ratio between a large and a small event and their corner frequencies by fitting the observed source spectral ratio with the ratio of source spectra which obeys the model (Miyake et al., 1999). This method has an advantage of removing site effects in evaluating the parameters. The best source model of the Tai-Tung mainshock in 2006 was estimated by comparing the observed waveforms with synthetics using empirical Green’s function method. The size of the asperity is about 3.5 km length along the strike direction by 7.0 km width along the dip direction. The rupture started at the left-bottom of the asperity and extended radially to the right-upper direction.

Huang, H.; Lin, C.

2010-12-01

329

Temporal Changes in Site Response Associated with the Strong Ground Motion of the 2004 Mw 6.6 Mid-Niigata  

E-print Network

earthquakes. The coseismic changes are followed by apparent recoveries, with the time scale ranging from several tens to more than 100 sec. The coseismic peak frequency drop, peak spectral ratio drop that at a given site the input ground motion plays an important role in controlling both the coseismic change

Black, Robert X.

330

Evidence for fault-related directionality and localized site effects from strong motion recordings of the 2003 Boumerdes (Algeria) earthquake: Consequences on damage distribution and the Algerian seismic code  

Microsoft Academic Search

The Algiers–Boumerdes region has been struck by a destructive magnitude 6.8 (Mw) earthquake on May 21, 2003. The study presented in this paper is based on main shock strong motions from 13 stations of the Algerian accelerograph network. A maximum 0.58g peak ground acceleration (PGA) has been recorded at 20km from the epicenter, only about 150m away from a PGA

Nasser Laouami; Abdennasser Slimani; Youcef Bouhadad; Jean-Luc Chatelain; Ali Nour

2006-01-01

331

Strong ground motion data recorded at the Idaho National Laboratory during the 1983 Borah Peak, Idaho earthquake. [Appendix contains plot generated by accelerogram showing peak valves amplitude, response spectra, displacement, veolocity and acceleration  

SciTech Connect

The Idaho National Engineering Laboratory (INEL) is located approximately 80 km southeast of the epicenter for the 1983 M{sub S} 7.3 Borah Peak Idaho earthquake. Thirteen strong-motion accelerographs located at various facilities around the INEL Site recorded strong-ground motions from the Borah Peak earthquake. The strong-motion records were digitized and processed resulting in corrected acceleration, velocity, and displacement time-histories and response and Fourier spectra. Peak horizontal accelerations had a range of 0.022 to 0.078 g for accelerographs located at free-field and basement sites. Values of 0.037 {minus} 0.817 g were recorded at accelerographs located within structures above basement level. Peak vertical accelerations ranged from 0.16 (basement level) to 0.059 g (top of structures). The peak amplitudes of the response and Fourier Spectra occur in the 2 -- 10 hz frequency range. Appendices include Borah Peak earthquake accelerograph data printouts. 8 refs., 4 figs., 7 tabs.

Jackson, S.M.; King, J.J.; Anderson, D.M.; Carpenter, G.S.; Adams, H.A.

1991-06-01

332

Analysis of Active Crustal Deformation in Chiayi Area, Southwestern Taiwan by Continues GPS network and numerical modeling  

NASA Astrophysics Data System (ADS)

Locating in the boundary between the Eurasia Plate and the Philippine Sea Plate, the island of Taiwan lies in a complex tectonic area. The fold-and-thrust belt in the southwestern Taiwan provides distinctive morphotectonic features reflecting the initial mountain building stage in Taiwan orogeny. Several devastating earthquakes have occurred in this region since 1900, the famous one is M7.1 Meishan earthquake in 1906. In addition, a seismic concentration zone is observed in Coastal plain in Chiayi counties, which no active faults have been reported in this region. The active deformation in SW Taiwan has been suggested to be related to active growing folding initiated by the blind thrust fault system. How surface deformation related to the subsurface active structures is a crucial topic for seismic hazard assessment in study area. The newly initiated blind fault system increases potential earthquake hazard in the southwestern alluvial plain where is densely populated. Thus we try to characterize the existence of blind fault-folding system beneath the coastal plain area by geodetic method. We derive a velocity field based on data at 55 continuous GPS (CGPS) stations from 2006 to 2010, and data at 97 campaign mode GPS over a time period between 2002 to 2010. The CGPS data used in this study were processed with the GAMIT/GLOBK software version 10.4. The crustal motion in this area shows the horizontal displacement about 30 mm/yr with the directions of 297° in the easternmost part of the Western Foothills, and crossing the main active structures, Chiushiunkeng-Chukou Fault and blind fault systems, the velocities significantly decrease to 3 mm/yr with the directions of 288° in the westernmost part in the coastal plan, with respect to Paisha station, S01R. The compressional strain rate dominates and the larger compressional strain rate is observed at the Foothill region, the east side of Chiushiunkeng- Chukou Fault. In some coordinate time-series of our CGPS sites, the strong periodic signals whether in horizontal component or vertical component is observed. These signals might include the effect of variation of ground water level or tectonic motion. In this study, we try to use the available geological structural profiles from CPC to characterize complex motions in Chiayi region and to assess the fault activity based on 2-D dislocation model. Further, we try to use Poly3D to inverse the fault motion during interseismic period.

Chung, W. C.; Hu, J. C.

2012-04-01

333

Deformation and seismicity of Taiwan  

PubMed Central

14C-dated Holocene coastal uplift, conventional and satellite geodetic measurements, and coseismic and aseismic fault slip reveal the pattern of distributed deformation at Taiwan resulting from convergence between the Philippine Sea plate and Eurasia; as in other subduction orogenic settings, the locus of strain release and accumulation is strongly influenced by changes in fault geometry across strike. Uplift evidence from the islands of Lutao and Lanhsu is consistent with progressive oblique collision between the Luzon arc and the Chinese continental margin. In the Coastal Range, geodetic and seismic records show that shortening is taken up serially by discontinuous slip on imbricate faults. The geodetic data point to net extension across the Central Range, but deformed Holocene shorelines in the Hengchun Peninsula at its southern extremity suggest that the extension is a superficial effect partly caused by blind reverse faulting. The fastest shortening rates indicated by geodesy are recorded on the Longitudinal Valley fault and across the Chukou fault within the fold-and-thrust belt. In the former, the strain is dissipated mainly as aseismic reverse and strike-slip displacement. In contrast, the fold-and-thrust belt has witnessed five earthquakes with magnitudes of 6.5 or above in the 20th century, including the 1999.9.21 Chi-Chi earthquake (magnitude ? 7.6) on a branch of the Chukou fault. The neotectonic and geodetic data for Taiwan as a whole suggest that the fold-and-thrust belt will continue to host the majority of great earthquakes on the island. PMID:11016964

Vita-Finzi, Claudio

2000-01-01

334

Deformation and seismicity of Taiwan.  

PubMed

14C-dated Holocene coastal uplift, conventional and satellite geodetic measurements, and coseismic and aseismic fault slip reveal the pattern of distributed deformation at Taiwan resulting from convergence between the Philippine Sea plate and Eurasia; as in other subduction orogenic settings, the locus of strain release and accumulation is strongly influenced by changes in fault geometry across strike. Uplift evidence from the islands of Lutao and Lanhsu is consistent with progressive oblique collision between the Luzon arc and the Chinese continental margin. In the Coastal Range, geodetic and seismic records show that shortening is taken up serially by discontinuous slip on imbricate faults. The geodetic data point to net extension across the Central Range, but deformed Holocene shorelines in the Hengchun Peninsula at its southern extremity suggest that the extension is a superficial effect partly caused by blind reverse faulting. The fastest shortening rates indicated by geodesy are recorded on the Longitudinal Valley fault and across the Chukou fault within the fold-and-thrust belt. In the former, the strain is dissipated mainly as aseismic reverse and strike-slip displacement. In contrast, the fold-and-thrust belt has witnessed five earthquakes with magnitudes of 6.5 or above in the 20th century, including the 1999.9.21 Chi-Chi earthquake (magnitude approximately 7.6) on a branch of the Chukou fault. The neotectonic and geodetic data for Taiwan as a whole suggest that the fold-and-thrust belt will continue to host the majority of great earthquakes on the island. PMID:11016964

Vita-Finzi, C

2000-10-10

335

Strong Libraries, Strong Scores  

ERIC Educational Resources Information Center

This article talks about the first-ever Texas Conference on School Libraries on April 6, 2005 that was attended by one hundred thirty-five school administrators and trustees. The miniconference, entitled Strong Libraries, Strong Scores, was held at the Austin Hilton, Austin, Texas during the Texas Library Association's Annual Conference and was…

Gray, Carlyn

2006-01-01

336

Post-Newtonian gravitational radiation and equations of motion via direct integration of the relaxed Einstein equations. V. Evidence for the strong equivalence principle to second post-Newtonian order  

SciTech Connect

Using post-Newtonian equations of motion for fluid bodies valid to the second post-Newtonian order, we derive the equations of motion for binary systems with finite-sized, nonspinning but arbitrarily shaped bodies. In particular we study the contributions of the internal structure of the bodies (such as self-gravity) that would diverge if the size of the bodies were to shrink to zero. Using a set of virial relations accurate to the first post-Newtonian order that reflect the stationarity of each body, and redefining the masses to include 1PN and 2PN self-gravity terms, we demonstrate the complete cancellation of a class of potentially divergent, structure-dependent terms that scale as s{sup -1} and s{sup -5/2}, where s is the characteristic size of the bodies. This is further evidence of the strong equivalence principle, and supports the use of post-Newtonian approximations to derive equations of motion for strong-field bodies such as neutron stars and black holes. This extends earlier work done by Kopeikin.

Mitchell, Thomas; Will, Clifford M. [McDonnell Center for the Space Sciences, Department of Physics, Washington University, St. Louis, Missouri 63130 (United States)

2007-06-15

337

Post-Newtonian gravitational radiation and equations of motion via direct integration of the relaxed Einstein equations. V. Evidence for the strong equivalence principle to second post-Newtonian order  

E-print Network

Using post-Newtonian equations of motion for fluid bodies valid to the second post-Newtonian order, we derive the equations of motion for binary systems with finite-sized, non-spinning but arbitrarily shaped bodies. In particular we study the contributions of the internal structure of the bodies (such as self-gravity) that would diverge if the size of the bodies were to shrink to zero. Using a set of virial relations accurate to the first post-Newtonian order that reflect the stationarity of each body, and redefining the masses to include 1PN and 2PN self-gravity terms, we demonstrate the complete cancellation of a class of potentially divergent, structure-dependent terms that scale as s^{-1} and s^{-5/2}, where s is the characteristic size of the bodies. This is further evidence of the Strong Equivalence Principle, and supports the use of post-Newtonian approximations to derive equations of motion for strong-field bodies such as neutron stars and black holes. This extends earlier work done by Kopeikin.

Thomas Mitchell; Clifford M. Will

2007-04-17

338

Taiwan Nantou County earthquake 0327 Taiwan Nantou County earthquake  

E-print Network

Taiwan Nantou County earthquake 20130327 1 #12;0327 Taiwan Nantou County earthquake Source, Intensity 5 #12;I II III IV V VI VII Intensity Shake map of the March 27 Earthquake The peak ground and Technology Center for Disaster Reduction (NCDR) #12;Earthquake Response and Evacuation are a Part of Students

339

Three-dimensional Qp- and Qs-tomography beneath Taiwan orogenic belt: implications for tectonic and thermal structure  

NASA Astrophysics Data System (ADS)

We determined the 3-D Qp- and Qs- structure of the Taiwan orogenic belt to enhance understanding of the related tectonic and thermal structure beneath the collision zone. The inversion used t* values measured from the spectra of P and S waves from the dense Taiwan strong motion network for moderate size earthquakes (ML 4.5-5.5) to avoid source complexity. The time period, 1991-2007, includes the aftershock sequence of the 1999 Chi-Chi earthquake that provides good ray coverage in central Taiwan. Over 18 000 velocity spectra from 883 earthquakes were analysed. A non-linear least square technique is applied to the spectra for t* determination by assuming a ?-2 source model for the frequency band of 1-30 Hz. A frequency-independent Q was assumed in this study. The corner frequency of a specific event was fixed for the corresponding stations, and a quality index was defined to assure good quality data for the inversion. The results reveal the sharp variation of Qp and Qs across the recently ruptured Chelungpu Fault, and the Kaoping and Chaochou Faults in Pingtung Plain. The Q values in the hangingwall are smaller by about 85 and 110 for Qp and Qs, respectively, relative to the footwall. The fault geometry is distinctly delineated by the contour of Qp/Qs of 1.2 that extends to the depth of the geologically identified décollement structure. Beneath the Central Range, the low Qp, low Qs and high Qp/Qs features coincide well with the aseismic zone. Comparison to the recent thermomechanical numerical models of Taiwan shows that the low Q zone corresponds to the exhumation of the lower crust. The low Qs regime (high attenuation) beneath the Central Ranges at the depth of 5-22 km coincides with predicted temperatures of 400-600 °C. The Qs comparison with the major tectonic and thermal mechanical models of Taiwan reveals that the shear wave attenuation model contains comprehensive rheological and thermal information of relevance to understanding mountain building processes. This technique appears particularly useful for distinguishing strong and weak crustal regions in the absence of other constraints.

Wang, Yu-Ju; Ma, Kuo-Fong; Mouthereau, Frederic; Eberhart-Phillips, Donna

2010-02-01

340

Can landslide-prone slope response to strong shaking be inferred from weak motion data? First answer from 2009 L'Aquila earthquake  

NASA Astrophysics Data System (ADS)

The complexity of factors controlling the dynamic response of marginally stable slopes and the scarcity of direct ground motion recordings acquired on landslide-prone areas make it difficult to evaluate the role of site response in seismic landslide triggering. A long term accelerometric monitoring, conducted at a tectonically and geomorphologically active site of Abruzzo in Central Italy (Caramanico Terme) has provided interesting evidence of amplification with a pronounced directional character parallel to the local slope direction on a landslide consisting of colluvial deposits overlying mudstone substratum. However, until 2008, these observations were based only on recordings of events of low to moderate magnitude. The 6.3 Mw earthquake that on 6 April 2009 hit L'Aquila, 60 km from Caramanico, allowed to test whether these previous findings hold true also for the landslide site response at higher shaking levels. The comparison of the 2009 mainshock recordings of the accelerometric station located on the landslide (CAR2) to those from two nearby stations, one sited on soft soils similar to landslide substratum (CAR1) and the other on colluvial material (CAR5), showed relative amplifications (in terms of peak horizontal acceleration PHA) very close to the average values estimated from smaller events (about 1.5 and 1.0 relatively to CAR1 and CAR5, respectively). The similarity of PHA observed on colluvium, regardless of its involvement in landsliding, confirmed that, in terms of total shaking energy, the main factor controlling amplification is the impedance contrast between colluvium and mudstone substratum. The comparison between the station on landslide and a reference station on rock (CAR4) showed a relative amplification increasing with magnitude, probably because of the stronger response of the rock site to the higher frequencies prevailing in wavetrains coming from nearby small sources. This suggests that in such cases amplification assessments based on weak motion data can lead to considerable underestimates. On the other hand, the landslide site response directivity showed similar properties for the entire range of the observed magnitudes (1.4 - 6.3). It is possible that in the near field source effects modify the ratio between directional maximum and minimum of shaking energy, without, however, significantly altering the orientation of shaking maxima. In terms of spectral properties, directivity of major peaks in horizontal to spectral ratios (HVSR) was the same at any magnitude, even though at higher magnitudes spectral ratio amplitudes tend to decrease at higher frequencies and increase at lower ones. However the comparison of HVSR with standard spectral ratios (SSR) between the station on landslide and the reference site on rock indicated that the inferences on resonance frequencies derived from single station seismic weak motion measurements (like HVSR) could be unreliable under the complex conditions of a landslide-prone slope. It appears that more reliable indications can be derived from ambient noise measurement acquired with velocimetric instruments. Thus, overall, weak motion recordings proved to provide useful information on landslide site response characteristics, especially having a dataset sufficiently differentiated in terms of azimuth location, distance, energy and source characteristics. However, the extrapolation of inferences based on recordings of small magnitude events to stronger earthquake scenarios requires some caution.

Del Gaudio, Vincenzo; Wasowski, Janusz

2010-05-01

341

Comparison of the low-cost MEMS accelerometers used by the Quake-Catcher Network and traditional strong motion seismic sensors  

NASA Astrophysics Data System (ADS)

Accelerometers based on low-cost micro-electro-mechanical systems (MEMS) have improved swiftly, making the rapid deployment of dense seismic arrays possible. For example, the Quake-Catcher Network (QCN) makes use of MEMS-based tri-axial sensors installed in homes and businesses to record earthquakes, with almost 2000 participants worldwide. QCN utilizes an open-source distributed-computing system, called the Berkeley Open Infrastructure for Network Computing (BOINC), to retrieve waveforms from continuous or triggered recordings back to the QCN server. Furthermore, the QCN approach can also be used to augment existing seismic networks for rapid-earthquake detection purposes, as well as studies on seismic source- and site-related phenomena. Following the 3 September 2010 Mw7.1 Darfield earthquake, 192 QCN stations were installed in a dense array to record the on-going aftershock sequence in and around the city of Christchurch. We examine the peak ground motions recorded during a M5.1 aftershock and find that peak ground acceleration (PGA) is spatially variable, but with a clear decay in amplitude with distance. In general, closely located GeoNet and QCN stations report similar PGA. Several QCN stations were located within 1 km of existing GeoNet stations, providing an opportunity to compare time series and amplitude spectra. For these closely spaced pairs of stations, the amplitude spectra observed from the horizontal components are highly correlated with average cross-correlation coefficients of 0.9 or higher. In addition, we find the correlation coefficient decreases with increasing distance between station pairs. In future work we will compare the instrumental sensitivity between traditional and MEMS-based sensors by conducting shake table tests of five different types of MEMS sensors at the Albuquerque Seismic Lab.

Cochran, E. S.; Lawrence, J.; Kaiser, A. E.; Fry, B.; Chung, A. I.; Evans, J. R.

2011-12-01

342

Holographic Screening Length on Parallel Motion of Quark-Antiquark Pair in Four Dimensional Strongly Coupled = 4 super-Yang-Mills plasma  

NASA Astrophysics Data System (ADS)

We study the screening length of a quark-antiquark pair moving in a strongly coupled hot plasma of = 4 super-Yang-Mills using AdS/CFT correspondence where the background metric is five dimensional AdS black hole. We take the string solution as such the separation length L of quark-antiquark pair is parallel to the string velocity v. The screening length and the bound energy are computed numerically using Mathematica. We find that the plots are bounded from below by some functions that are related to the momentum flow of the drag force configuration Pc. We compare the result by computing the screening length in the quark-antiquark reference frame by boosting the AdS black hole.

Nata Atmaja, Ardian

2014-10-01

343

Shear Wave Structure of Umbria and Marche, Italy, Strong Motion Seismometer Sites Affected by the 1997-98 Umbria-Marche, Italy, Earthquake Sequence  

USGS Publications Warehouse

A long sequence of earthquakes, eight with magnitudes between 5 and 6, struck the Umbria and Marche regions of central Italy between September 26, 1997 and July 1998. The earthquake swarm caused severe structural damage, particularly to masonry buildings, and resulted in the loss of twelve lives and about 150 injuries. The source of the events was a single seismogenic structure that consists of several faults with a prevailing northwest-southeast strike and crosses the Umbria-Marche border. The focal mechanism of the largest shocks indicates that the events were the product of shallow extensional normal faulting along a NE-SW extension perpendicular to the trend of the Apennines. The network of analog seismometer stations in the Umbria and Marche regions recorded motions of the main September and October 1997 events and a dense array of mobile digital stations, installed since September 29, recorded most of the swarm. The permanent national network Rete Accelerometrica Nazionale (RAN) is administered and maintained by Dipartimento delle Protezione Civile (DPC: Civil Protection Department); the temporary array was managed by Servizio Sismico Nazionale (SSN) in cooperation with small agencies and Universities. ENEA, the operator of many seismometer stations in Umbria, is the public Italian National Agency for New Technologies, Energy and the Environment. Many of the temporary and permanent stations in the Italian seismic network have little or no characterization of seismic velocities. In this study, we investigated 17 Italian sites using an active-source approach that employs low frequency harmonic waves to measure the dispersive nature of surface waves in the ground. We used the Spectral Analysis of Surface Wave (SASW) approach, coupled with an array of harmonic-wave electro-mechanical sources that are driven in-phase to excite the ground. An inversion algorithm using a non-linear least-squares best-fit method is used to compute shear wave velocities for up to 100 meters of the soil column. A draft report was published in the summer of 2008, followed by a comment period, lengthy discussions with Italian colleagues, and improved knowledge of the subsurface at the sites from soil logs. Four of the sites were reprocessed in order to correct issues with phase unwrapping of the field dispersion curves that complicated the velocity profile calculations at the lowest velocity sites. This report presents the final results from the reprocessing effort.

Kayen, Robert; Scasserra, Giuseppe; Stewart, Jonathan P.; Lanzo, Giuseppe

2008-01-01

344

Numerical studies on Heavy Rainfall Events over Northern Taiwan in Mei-Yu Season  

NASA Astrophysics Data System (ADS)

Two unusual heavy rainfall events occurred in northern Taiwan from late evening of 11 June to the early morning of 12 June 2012 and late evening of 2 June to the early morning of 3 June 1984. In a few hours, more than 400 mm rainfall were recorded over northwestern Taiwan in these two events. The mechanisms for the commencement and maintenance of this localized heavy rainfall events over northern Taiwan are investigated using the NCEP global grid data, satellite imageries, radar reflectivities, and simulations from the Weather Research and Forecast (WRF) model. These events occurred under favorable large-scale environment that included: upper-level divergence; low-level high equivalent potential temperature; low level of free convection (LFC); and subsynoptic-scale ascending motion over the northern Taiwan Strait and northern Taiwan. In the late night of 2 June, the main heavy rainfall area is simulated to the southeast of the low-level windshift line associated with a trough axis, which is located in the southeastern China coast. The simulated heavy rainfall area moves eastward toward northeastern Taiwan Strait and the northwestern coast of Taiwan as the windshift line continues to propagate eastward. The heavy convective rainfall is enhanced in the eastern Taiwan Strait by orographic blocking where the prevailing southwesterly wind within the Taiwan Strait converges with the orographically deflected flow with a southerly wind component off the western/northwestern Taiwan coast. As the simulated convective area continues to move toward northern Taiwan, it intensifies in a localized low-level convergence area over the northeastern Taiwan Strait and northwestern coast of Taiwan where a barrier jet along the coast converges with the northwesterly winds behind the surface front. Furthermore, in the early morning of 3 June, the simulated rainfall is heavier where the barrier jet encounters the leading edge of the cold pool caused by rain evaporative cooling. As the convective systems drift inland, the orographic lifting of the pre-frontal southwesterly flow helps to produce higher simulated rainfall intensity in the southern slopes of the Taipei Basin. The simulated daily accumulated rainfall over the Taipei Basin and northwestern coast of Taiwan is about 200 and 400 mm, respectively, about 50 mm less than observed. In an experiment without Taiwan's topography (the NT run), the simulated rainfall intensity over the northern Taiwan Strait and the northwestern coast of Taiwan is much less. In contrast to the control run, despite the presence of favorable large-scale settings, no convective systems move to the northern part of Taiwan from the northern Taiwan Strait in the NT run without heavy rainfall simulated over northern Taiwan. Two events will be comparatively investigated by WRF on the formation and maintainence of heavy rainfall in Mai-Yu season.

Lin, Pay-Liam

2014-05-01

345

Gravity features of the mud diapirs off southwest Taiwan  

NASA Astrophysics Data System (ADS)

Both the overpressure and buoyancy phenomena are generally used to account for the formation of submarine mud diapirs. According to the distribution of the mud diapirs and structural features, the compressive stress should play an important role on the formation of the mud diapirs in the offshore area of southwest Taiwan. Onland Taiwan, the Tainan and Chungchou anticlinal structures (associated with mud diapirs) reveal positive gravity anomalies. The mud diapirs off SW Taiwan are considered to be more active than onshore diapirs. However, the gravity nature of the submarine mud diapirs is not clear. In 2012 and 2013, we have collected shipboard gravity data by using R/V Ocean Researcher I in the offshore area of southwest Taiwan. Several NW-SE trending gravity profiles show a sharp drop across the Kaoping Canyon. By removing the gravimetric effect from the water-sediment interface, we find that the density contrasts of the mud diapirs with respect to the surrounding strata are generally positive. The results seem conflict with the buoyant force that triggers the upward motion of the mud diapirs. In this study, we will show some possible mechanisms to explain the gravity nature of the submarine mud diapirs.

Doo, W.; Hsu, S.; Huang, Y.; Chen, S.

2013-12-01

346

Source rupture process of the 5 September 2012 Costa Rica Mw=7.6 thrust event from joint inversion of high-rate GPS, strong motion, and teleseismic P wave data  

NASA Astrophysics Data System (ADS)

On 5 September 2012, a large thrust event (Mw=7.6) ruptured a densely instrumented seismic gap on the shallow plate boundary beneath the Nicoya Peninsula, Costa Rica. Networks of strong motion accelerometers, broadband and short-period sensors, and high-rate (5-sps) GPS stations recorded ground motions directly above the rupture zone, providing a unique opportunity to study the detailed source process of a large shallow megathrust rupture using nearby land observations. An inland and relatively deep hypocenter (10.086°N, 85.305°W, 40 km) was estimated by the USGS, and teleseismic W-phase inversions also indicate a relatively large (30-40 km) centroid depth. Hypocenter relocation performed using the local seismic network data indicates that the event initiated with small emergent seismic waves from a hypocenter ~10 km offshore (9.80°N, 85.53°W) 15 km deep on the megathrust. The local origin time (14:42:05) is 3 s earlier than the USGS origin time, compatible with the shallower source depth. A joint finite-fault inversion of 0.2 Hz lowpass-filtered hr-GPS recordings, <0.4 Hz ground velocity recordings from regional strong-motion sensors, and teleseismic P waves reveals that the primary slip zone is located beneath the Nicoya coastline up-dip from the USGS location. Complete ground motions are computed for the hr-GPS stations using a 1D regional velocity model and a wavenumber integration program from Robert Herrmann. The large-slip region extends ~50 km along strike and ~30 km along dip, with a centroid depth of ~23 km. The maximum slip is ~4 meters and Mw=7.6, consistent with teleseismic estimates. The inversion indicates that the rupture propagated down-dip from the offshore hypocenter with a rupture velocity of ~2.5 km/s. The inversion has limited resolution of any offshore slip, but slip occurred in a region about 30 km offshore along the northern half of the rupture zone. We consider the relationship between coseismic slip location, aftershocks and adjacent tremor and slow-slip regions.

Lay, T.; Yue, H.; Rivera, L. A.; Schwartz, S. Y.; Protti, M.

2013-05-01

347

Progress and Prospect of Physics Research and Education in Taiwan  

NASA Astrophysics Data System (ADS)

Started about two decades ago, the global trend of shifting industrial manufacture power from western developed countries toward developing countries in Asia has in turn become the impetus in building up physical science and research in these areas. A very good example is the remarkable progress of physical research and education in Taiwan, in terms of quantity and quality. The continuous elevation of Taiwan's high education into graduate level plus the government's strong commitment to research and development on a level of 2.62 % GDP have led to an impressive physics program with an annual budget ˜32 million USD from National Science Council in supporting 568 PIs. The investigation scope encompasses high energy and astrophysics, nano and condensed matter, and semiconductor, optoelectronic physics, etc. The former is vigorously conducted via international collaborative efforts of LHC, KEK, ALMA, Pan-STARRS, etc. The latter is driven by vital Taiwan high tech industry mostly semiconductor IC and optoelectronics flourished during this period. The early trend of outflows of BS physics majors to western world for advanced studies has reversed dramatically. Nearly 80% of the BS students continue their MS and PhD degrees in Taiwan, attracted by lucrative job markets of high tech industry. In addition, healthy inflow of high-quality science manpower of well trained PhDs and senior scholars returning to homeland has strengthened the competitiveness. Overall, the physics community in Taiwan is thriving. The annual Physical Society meeting is expanding at a rate of 6%, reaching ˜1800 attendants and 1200 papers, and dedicated to promotions of female physicists and students. The publication quantity of Taiwan in top journals of PRs and PRL is ranked among top 20^th for all fields of physics, and ranked the 6^th in APL. Clearly Taiwan has now emerged as a strong power in applied science, not limited by its population size. Concerted efforts on scientific exchanges are being taken to connect to international societies. The bright outlook of physical science and its vital power in Taiwan is anticipated to provide a stimulus to benefit South East Asia, and have far-reaching impacts on China and worldwide.

Raynien Kwo, J.

2010-03-01

348

Combining strong-motion, InSAR and GPS data to refine the fault geometry and source kinematics of the 2011, Mw 6.2, Christchurch earthquake (New Zealand)  

NASA Astrophysics Data System (ADS)

The space-time distribution of coseismic slip of the 2011 February 21, Mw 6.2, Christchurch earthquake, New Zealand, is explored, differently from all previous studies, through a joint inversion of geodetic and strong-motion data. The geodetic data consist of both global position system (GPS), from campaign and continuous stations, and synthetic aperture radar (SAR) interferograms from two ascending satellite tracks. The strong motion data consist of 10 stations located in the Canterbury plains, these stations offering a good azimuthal coverage of the event. The kinematic rupture model for the analysed event was obtained using the parametrization and non-linear inversion scheme proposed by Delouis et al. In particular, for any subfault we explore for the local source time function (local slip history), slip direction and rupture onset time. The geometry of the fault plane used for the kinematic inversion is inferred from the analysis of the geodetic data. To validate our results we perform a resolution study for both the single and complete data sets, and an errors analysis of our final kinematic rupture model. Considering the complexity highlighted by superficial deformation data, we adopted a fault model consisting of two partially overlapping segments, with dimensions 15 × 11 and 7 × 7 km2, corresponding to different faulting types. This two-fault model, instead of single-fault model, is needed to reconstruct the complex shape of the superficial deformation data. The total seismic moment resulting from the joint inversion is 3.0 × 1025 dyne · cm (Mw = 6.2) with an average rupture velocity of 2.0 km s-1.

Toraldo Serra, Eugenio Maria; Delouis, Bertrand; Emolo, Antonio; Zollo, Aldo

2013-09-01

349

Korean restaurant business plan in Taiwan  

E-print Network

Taiwan's food and beverage business has been one of the main drivers of the country's economic growth for the past several years. As Taiwan becomes more prosperous and grows beyond the traditional OEM/ODM businesses, ...

Chen, Kai Wei Kevin

2013-01-01

350

Surface waves in the western Taiwan coastal plain from an aftershock of the 1999 Chi-Chi, Taiwan, earthquake  

USGS Publications Warehouse

Significant surface waves were recorded in the western coastal plain (WCP) of Taiwan during the 1999 Chi-Chi, Taiwan, earthquake and its series of aftershocks. We study in detail the surface waves produced by one aftershock (20 September 1999, 18hr 03m 41.16sec, M 6.2) in this paper. We take the Chelungpu-Chukou fault to be the eastern edge of the WCP because it marks a distinct lateral contrast in seismic wave velocities in the upper few kilometers of the surface. For many records from stations within the WCP, body waves and surface waves separate well in both the time domain and the period domain. Long-period (e.g., >2 sec) ground motions in the plain are dominated by surface waves. Significant prograde Rayleigh wave particle motions were observed in the WCP. The observed peak ground velocities are about 3-5 times larger than standard predictions in the central and western part of the plain. Observed response spectra at 3 sec, 4 sec, and 5 sec at the center of the plain can be 15 times larger than standard predictions and 10 times larger than the predictions of Joyner (2000) based on surface wave data from the Los Angeles basin. The strong surface waves were probably generated at the boundary of the WCP and then propagated toward the west, largely along radial directions relative to the epicenter. The geometry of the boundary may have had a slight effect on propagation directions of surface waves. Group velocities of fundamental mode Rayleigh and Love waves are estimated using the multiple filter analysis (MFA) technique and are refined with phase matched filtering (PMF). Group velocities of fundamental mode surface waves range from about 0.7 km/sec to 1.5 km/sec for the phases at periods from 3 sec to 10 sec. One important observation from this study is that the strongest surface waves were recorded in the center of the plain. The specific location of the strongest motions depends largely on the period of surface waves rather than on specific site conditions or plain structures. Accordingly, we conjecture that surface waves could be generated in a wide area close to boundaries of low-velocity sedimentary wave guides. In the case studied in this article the area can be as wide as 30 km (from the Chelungpu fault to the center of the plain). Surface waves converted by P and S waves at different locations would overlap each other and add constructively along their propagation paths. As a result, the surface waves would get stronger and stronger. Beyond a certain distance to the boundary, no more surface waves would be generated. Consequently, no more local surface waves would be superimposed into the invasive surface waves, and the surface waves would tend to decay in amplitude with distance.

Wang, G.-Q.; Tang, G.-Q.; Boore, D.M.; Van Ness, Burbach, G.; Jackson, C.R.; Zhou, X.-Y.; Lin, Q.-L.

2006-01-01

351

Motion graphs  

Microsoft Academic Search

In this paper we present a novel method for creating realistic, controllable motion. Given a corpus of motion capture data, we automatically construct a directed graph called a motion graph that encapsulates connections among the database. The motion graph consists both of pieces of original motion and automatically generated transitions. Motion can be generated simply by building walks on the

Lucas Kovar; Michael Gleicher; Frederic H. Pighin

2002-01-01

352

75 FR 61175 - Polyvinyl Alcohol From Taiwan  

Federal Register 2010, 2011, 2012, 2013

...731-TA-1088 (Final)] Polyvinyl Alcohol From Taiwan AGENCY: United States International...less-than-fair-value imports from Taiwan of polyvinyl alcohol, provided for in subheading 3905.30...of Commerce that imports of polyvinyl alcohol from Taiwan are being sold in the...

2010-10-04

353

Quantifying the seismicity on Taiwan  

NASA Astrophysics Data System (ADS)

We quantify the seismicity on the island of Taiwan using the frequency-magnitude statistics of earthquakes since 1900. A break in Gutenberg-Richter scaling for large earthquakes in global seismicity has been observed, this break is also observed in our Taiwan study. The seismic data from the Central Weather Bureau Seismic Network are in good agreement with the Gutenberg-Richter relation taking b ? 1 when M < 7. For large earthquakes, M ? 7, the seismic data fit Gutenberg-Richter scaling with b ? 1.5. If the Gutenberg-Richter scaling for M < 7 earthquakes is extrapolated to larger earthquakes, we would expect a M > 8 earthquake in the study region about every 25 yr. However, our analysis shows a lower frequency of occurrence of large earthquakes so that the expected frequency of M > 8 earthquakes is about 200 yr. The level of seismicity for smaller earthquakes on Taiwan is about 12 times greater than in Southern California and the possibility of a M ? 9 earthquake north or south of Taiwan cannot be ruled out. In light of the Fukushima, Japan nuclear disaster, we also discuss the implications of our study for the three operating nuclear power plants on the coast of Taiwan.

Wu, Yi-Hsuan; Chen, Chien-Chih; Turcotte, Donald L.; Rundle, John B.

2013-07-01

354

Connectivity of the Taiwan, Cheju, and Korea straits  

NASA Astrophysics Data System (ADS)

Insight into the circulation of the East China Sea and origin of the Tsushima Current are investigated through direct, concurrent measurements of velocities through the Taiwan, Cheju, and Korea Straits. Current data are obtained from six bottom-mounted acoustic Doppler current profilers (ADCPs) arrayed along a section spanning the Korea Strait, a single bottom-moored ADCP in the Cheju Strait, and four bottom-moored ADCPs along a section spanning the Taiwan Strait. Mass transports are computed for the October-December, 1999 time period. In addition, temperature and salt transports are examined in conjunction with climatological values of temperature and salinity. Average volume transport is 0.14 Sverdrups (Sv) through the Taiwan Strait, 0.59 Sv for the Cheju Strait, and 3.17 Sv for the Korea Strait. Salt and temperature transport through the Korea Strait and into the Japan/East Sea are 110.48×10 6 kg/s and 0.24×10 15 watts (W), respectively. Heat loss in the East China Sea is approximately 200 W/ m2. Winds affect the transports in each of the straits. Most noticeable wind effects are observed in the Taiwan Strait where strong north wind events force flow into the South China Sea. The main source for the Tsushima Current and its flow into the Japan/East Sea is clearly the Kuroshio for fall, 1999.

Teague, W. J.; Jacobs, G. A.; Ko, D. S.; Tang, T. Y.; Chang, K.-I.; Suk, M.-S.

2003-01-01

355

The 5 September 2012 Nicoya, Costa Rica Mw 7.6 earthquake rupture process from joint inversion of high-rate GPS, strong-motion, and teleseismic P wave data and its relationship to adjacent plate boundary interface properties  

NASA Astrophysics Data System (ADS)

On 5 September 2012, a large thrust earthquake (Mw 7.6) ruptured a densely instrumented seismic gap on the shallow-dipping plate boundary beneath the Nicoya Peninsula, Costa Rica. Ground motion recordings directly above the rupture zone provide a unique opportunity to study the detailed source process of a large shallow megathrust earthquake using very nearby land observations. Hypocenter relocation using local seismic network data indicates that the event initiated with small emergent seismic waves from a hypocenter ~10 km offshore, 13 km deep on the megathrust. A joint finite-fault inversion using high-rate GPS, strong-motion ground velocity recordings, GPS static offsets, and teleseismic P waves reveals that the primary slip zone (slip > 1 m) is located beneath the peninsula. The rupture propagated downdip from the hypocenter with a rupture velocity of ~3.0 km/s. The primary slip zone extends ~70 km along strike and ~30 km along dip, with an average slip of ~2 m. The associated static stress drop is ~3 MPa. The seismic moment is 3.5 × 1020 Nm, giving Mw = 7.6. The coseismic large-slip patch directly overlaps an onshore interseismic locked region indicated by geodetic observations and extends downdip to the intersection with the upper plate Moho. At deeper depths, below the upper plate Moho, seismic tremor and low-frequency earthquakes have been observed. Most tremor locates in adjacent areas of the megathrust that have little coseismic slip; a region of prior slow slip deformation to the southeast also has no significant coseismic slip or aftershocks. An offshore locked patch indicated by geodetic observations does not appear to have experienced coseismic slip, and aftershocks do not overlap this region, allowing the potential for a comparable size rupture offshore in the future.

Yue, Han; Lay, Thorne; Schwartz, Susan Y.; Rivera, Luis; Protti, Marino; Dixon, Timothy H.; Owen, Susan; Newman, Andrew V.

2013-10-01

356

Strategic planning of developing automatic optical inspection (AOI) technologies in Taiwan  

NASA Astrophysics Data System (ADS)

In most domestic hi-tech industries in Taiwan, the automatic optical inspection (AOI) equipment is mostly imported. In view of the required specifications, AOI consists of the integration of mechanical-electrical-optical-information technologies. In the past two decades, traditional industries have lost their competitiveness due to the low profit rate. It is possible to promote a new AOI industry in Taiwan through the integration of its strong background in mechatronic technology in positioning stages with the optical image processing techniques. The market requirements are huge not only in domestic need but also in global need. This is the main reason to promote the AOI research for the coming years in Taiwan. Focused industrial applications will be in IC, PCB, LCD, communication, and MEMS parts. This paper will analyze the domestic and global AOI equipment market, summarize the necessary fish bone technology diagrams, survey the actual industrial needs, and propose the strategic plan to be promoted in Taiwan.

Fan, K. C.; Hsu, C.

2005-01-01

357

Taiwan`s experience with municipal waste recycling  

SciTech Connect

Currently, each person on the average produces 1.15 kg of the municipal waste per day and a total of 9 million metric tons were generated annually in Taiwan. The disposal of such a huge amount of waste presents tremendous challenge for the island due to the scarcity of landfills and incineration facilities available locally. EPA of Taiwan, R.O.C. thus takes an active role in promoting waste recycling to reduce the garbage produced in municipalities. In order to efficiently utilize the government`s human and financial resources used in recycling, started from January 31, 1989, EPA has mandated the producer responsibility recycling program for several designated post-consumer products such as PET, PVC bottles, scrap tires, scrap motor vehicles, etc. Producer responsibility recycling program specifies that the manufacturers, importers and sellers of these designated products have the responsibility to retrieve their products and recycle them properly. Several negative effects have been encountered while the implementation of this producer responsibility recycling program in Taiwan which resulted in a modification of this recycling program recently. This paper presents the encountered experiences on the implementation of municipal waste recycling program in Taiwan.

Lee, C.H. [Da-Yeh Univ., Chang-Hwa (Taiwan, Province of China)

1998-12-31

358

Fault-plane Identification and Focal Mechanism of the 2003 Chengkung Earthquake Sequence, at East Taiwan  

NASA Astrophysics Data System (ADS)

Two subduction systems are taken place around Taiwan Island respectively to the north and to the south. In between, the arc-continent collision proceeds at east Taiwan along the Longitudinal Valley fault. The Chengkung Earthquake, MW 6.5 December 10 2003 at the southern part of the Longitudinal Valley fault, is a typical thrust reflecting release of stress/strain accumulated in the eastern collision framework. Such earthquake sequence contains a seismicity distribution roughly covered a region of 40 km by 40 km, which compose of a thrust fault dipping to the east. According to the focal mechanism of the main shock and the spatial distribution of aftershocks, the mainly crustal movement in the Chengkung earthquake can therefore be recognized as a rupturing with an east-dip plane and thrusting toward the west. However, 15 larger aftershocks occurred 7 days after the main shock showed a more complicated tectonic setting around this area. In the offshore area, three aftershocks illustrated normal-fault-type deformation, which is rarely observed in this area. On land, the larger aftershocks exhibited oblique thrust deformation along the Longitudinal Valley fault. In order to better understand the seismotectonic setting in this earthquake, a waveform inversion was applied to refine the focal mechanism solutions and identify the fault plane from one or multiple seismic recordings at short epicentral distance. Kanamori et al., (1990) and Singh et al., (1997) showed clear examples of local events for which source parameters could be well constrained by using near-field waves, even with a single station. However, when surface ruptures are not observed, as in the case of too small events or blind faults, the fault plane may be undetermined. The method used in this study includes the effect of source finiteness directly in the inversion process, allowing us to invert sparse, near-field data for focal mechanism and fault plane determination simultaneously. Seven parameters, including the strike, dip, rake, and dislocation, were explored with a grid search and minima of the misfit error between the observed and calculated seismograms. The seismograms considered here are in displacement integrated from three-component strong-motion record, organized by the Central Weather Bureau of Taiwan. We have identified three groups of aftershocks showing nearly identical focal mechanisms in the Chengkung sequence, which have initially compiled by the BATS (Broadband Array in Taiwan for seismology), Academia Sinica of Taiwan. Each of these groups have been examined their spatial attitudes of fault plane and refined their focal mechanisms. Our results show a segmented rupture at the southern part of the Longitudinal Valley fault, and a deformation accommodation as function of space can be inferred in the Chengkung sequence. In comparison with the historical earthquake taken place in the late 1951 at the almost location, the Chengkung sequence is probably the reactivated rupture along the same fault segment, suggesting that the temporal and spatial rupture pattern was repeated.

Chang, T.; Delouis, B.

2004-12-01

359

Orientation and Mobility in Taiwan.  

ERIC Educational Resources Information Center

This article describes a three-month orientation and mobility (O&M) program conducted for four potential teachers of individuals with blindness in Taipei (Taiwan). Challenges in residential areas, business areas, buildings, and use of mass transit are illustrated. Although the travel environments were more complex than those in the United States,…

Leja, James A.

1993-01-01

360

Reconstructing Transition Knowledge in Taiwan  

ERIC Educational Resources Information Center

Taking a post-colonial stand and using school to work transition as an example, the author re-examines the special education discourses in Taiwan and attempts to construct alternate understandings of transition from sociological and cultural perspectives. A review of past transition literature and a survey of the educational background of the…

Cheng, Chen-chen

2012-01-01

361

Introduction to National Taiwan University  

E-print Network

Arts Science Medicine Law Bioresources & Agriculture Engineering Academic Programs 2 Professional University 1928 #12;National Taiwan University 6 Colleges Liberal Arts Law Science Agriculture Medicine (CNRS, UPMC, and INRIA) #12;International Cutting-edge Research Centers California NanoSystems Institute

Wu, Yih-Min

362

Principal Leadership in Taiwan Schools  

ERIC Educational Resources Information Center

During the past two decades, Taiwan's Ministry of Education has responded to globalization by restructuring school curricular, instructional, and decision making practices along western lines in an attempt to attain legitimacy on the world stage. As a result, Taiwanese principals, once kings within their schools, now must share power with other…

Shouse, Roger C.; Lin, Kuan-Pei

2010-01-01

363

Faculty autonomy: Perspectives from Taiwan  

Microsoft Academic Search

Recent legislative initiatives indicate thatlong-standing traditions of centralized state controlof higher education in Taiwan are being displaced bynew arrangements emphasizing institutional autonomy. Autonomous institutions are assumed to be flexible andresponsive, given their relative freedom fromgovernment control. Institutional autonomy is assumedto ``trickle down'' to organizational members, who arethen empowered to devise unique solutions to solveparticular problems. Asserted benefits ofinstitutional autonomy may

Jay R. Dee; Alan B. Henkin; Jessica Hsin-Hwa Chen

2000-01-01

364

Calibration of PS09, PS10, and PS11 trans-Alaska pipeline system strong-motion instruments, with acceleration, velocity, and displacement records of the Denali fault earthquake, 03 November 2002  

USGS Publications Warehouse

In September, 2003, the Alyeska Pipeline Service Company (APSC) and the U.S. Geological Survey (USGS) embarked on a joint effort to extract, test, and calibrate the accelerometers, amplifiers, and bandpass filters from the earthquake monitoring systems (EMS) at Pump Stations 09, 10, and 11 of the Trans-Alaska Pipeline System (TAPS). These were the three closest strong-motion seismographs to the Denali fault when it ruptured in the MW 7.9 earthquake of 03 November 2002 (22:12:41 UTC). The surface rupture is only 3.0 km from PS10 and 55.5 km from PS09 but PS11 is 124.2 km away from a small rupture splay and 126.9 km from the main trace. Here we briefly describe precision calibration results for all three instruments. Included with this report is a link to the seismograms reprocessed using these new calibrations: http://nsmp.wr.usgs.gov/data_sets/20021103_2212_taps.html Calibration information in this paper applies at the time of the Denali fault earthquake (03 November 2002), but not necessarily at other times because equipment at these stations is changed by APSC personnel at irregular intervals. In particular, the equipment at PS09, PS10, and PS11 was changed by our joint crew in September, 2003, so that we could perform these calibrations. The equipment stayed the same from at least the time of the earthquake until that retrieval, and these calibrations apply for that interval.

Evans, John R.; Jensen, E. Gray; Sell, Russell; Stephens, Christopher D.; Nyman, Douglas J.; Hamilton, Robert C.; Hager, William C.

2006-01-01

365

Seismic Hazard and Ground Motions  

Microsoft Academic Search

North America (ENA) makes it difficult to reliably estimate strong ground motions for future earthquake events in the region. The stochastic modeling approach (SMA), in combination with a seismological source model to describe the spectral amplitudes of the ground motion and their scaling with earthquake size, is arguably the only viable method of ground motion prediction in ENA. Abundance of

B. Halldórsson; A. S. Papageorgiou

366

Queering Taiwan: in search of nationalism's other.  

PubMed

This article deals with the formation of Taiwan’s homosexual cultural politics in the 1990s, the impact and implications of which are yet to be examined within the larger context of Taiwan’s cultural and political development and ethnic relationships. It is argued that the rise of this cultural politics is both a reflection and a source of a growing sense of identity crisis on the island. By examining the configurations of “queer” in various discursive domains, this interdisciplinary study seeks to delineate the cross-referencing ideological network of this cultural movement and its entanglement with the complexity of Taiwan’s nationalism. At the same time, to the extent that this movement tends to present itself as a radical politics from a privileged epistemological and cultural standpoint, this claimed radicalism is also scrutinized for its problematics and ironies. PMID:21966703

Chen, Li-fen

2011-01-01

367

Motion Commotion  

NSDL National Science Digital Library

Students learn why and how motion occurs and what governs changes in motion, as described by Newton's three laws of motion. They gain hands-on experience with the concepts of forces, changes in motion, and action and reaction. In an associated literacy activity, students design a behavioral survey and learn basic protocol for primary research, survey design and report writing.

Integrated Teaching And Learning Program

368

Network & cooperation in translating Taiwan in English: With reference to translation of modern Taiwan literature  

Microsoft Academic Search

The translation of Taiwan literature has been carried out by the source culture for last three decades, mainly aiming at making its literary voice heard in the West and ultimately presenting Taiwan culturally and literally. However, such task is never easy, especially when the minor literature, such as Taiwan literature, is translated and exported into the dominant Anglo-American culture. The

Szu-Wen Cindy Kung

369

Observation on Foreign Children's Literature in Taiwan: The Future of Local Children's Literature in Taiwan  

Microsoft Academic Search

Formosa-Taiwan is a small island with a unique culture. Because of its blood relationship with China, Taiwan inherits the traditional Chinese cultural features from mainland China. Inside Taiwan, the indigenous cultures are going to fade, while the increasing number of the children of foreign brides will play an important role in the future. On the other hand, culture from Japan

Han-Lin Lin

2006-01-01

370

Arsenic and Humic Substances in Alluvial Aquifers of Bangladesh and Taiwan: A Comparative Study  

NASA Astrophysics Data System (ADS)

Humic substances in groundwater samples from the arsenicosis area in Bangladesh, northern Taiwan and the Blackfoot disease (BFD) area in southwestern Taiwan were characterized by Fluorescence Spectroscopy (FS), and Fourier Transform Infrared Spectroscopy (FTIR) analyses. As, Mn, Fe, Sr, Se levels in these groundwaters were measured by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). Major ions and selected water parameters including pH, electrical conductivity (EC), oxidation reduction potential (ORP), and dissolved oxygen (DO) were also determined. Groundwater As concentration ranges from 1.4 to 140 ?g/L in the alluvial aquifers located in the Chapai-Nawabganj district of Bangladesh. As levels in groundwater ranges from 0.5 to 560 ?g/L in the Ilan Plain of northern Taiwan. Geothermal waters in the Beitou hot springs contain high concentrations of inorganic As (up to 3,975 ?g/L); geothermal activity is likely responsible for the significant discharge of arsenic to the downstream Kwandu Plain. As levels in the BFD area of southwestern Taiwan ranges from 25 ?g/L to 967 ?g/L. Interestingly, groundwater arsenic in the BFD area of southwestern Taiwan correlates positively with strong fluorescence (maximum relative fluorescence intensity upto 495) and the content of humic substances. In contrast, As-rich groundwaters from Chapai-Nawabganj district of Bangladesh and northern part of Taiwan generally have relatively low content of humic substances with weak fluorescence (maximum relative fluorescence intensity upto 65 and 121, respectively). Moreover, results of FTIR analysis show that humic substances extracted from water samples of the Taiwan BFD area contain phenolic and amines groups of humic substances, which tend to form organo-metal complexes with As and other trace elements. High levels of As and humic substances probably play a critical role in causing the Black foot disease in Chia-Nan plain of southwestern Taiwan.

Reza, A.; Jean, J.; Lee, M.

2007-12-01

371

Strong Interaction  

SciTech Connect

We will give here an overview of our theory of the strong interactions, Quantum Chromo Dynamics (QCD) and its properties. We will also briefly review the history of the study of the strong interactions, and the discoveries that ultimately led to the formulation of QCD. The strong force is one of the four known fundamental forces in nature, the others being the electromagnetic, the weak and the gravitational force. The strong force, usually referred to by scientists as the 'strong interaction', is relevant at the subatomic level, where it is responsible for the binding of protons and neutrons to atomic nuclei. To do this, it must overcome the electric repulsion between the protons in an atomic nucleus and be the most powerful force over distances of a few fm (1fm=1 femtometer=1 fermi=10{sup -15}m), the typical size of a nucleus. This property gave the strong force its name.

Karsch, F.; Vogelsang, V.

2009-09-29

372

Taiwan Earthquake Damage Index Sin Mei Nga* and Masataka Andob a* Department of Geology, Chinese Culture University, No. 55, Hwa-Kang Road, Yang-Ming-Shan, Taipei 11114, Taiwan b Institute of Earth Sciences, Academia Sinica, 128, Sec2, Academia Road, Nangang, Taipei 11529, Taiwan * Corresponding author. Tel.: +886 (02) 28 61 05 11 ext.26133 fax: +886 (02) 28 61 49 59 E-mail: wsw2@ulive.pccu.edu.tw or sin_mei_josephine_ng@hotmail.com  

NASA Astrophysics Data System (ADS)

Taking advantage of a previous study and twelve-year, free-field strong motion data in Taiwan, a preliminary, five-level earthquake damage index is newly proposed: I-No (no damage), II-Very Light, III-Light, IV-Moderate, and V-Heavy. For index I, PGA and PGV are, respectively, <62.5 gal and <11 cm/s. Likewise, for index II, PGA is ?62.5 and ?187.5 gal; but, PGV is ?11 and ?35 cm/s. Similarly, PGA is ?187.5 and ?325 gal; but, PGV is ?35 and ?55 cm/s for index III. The corresponding PGA and PGV, for index IV, are ?325 and ?450 gal and ?55 and ?75 cm/s. Finally, for index V, PGA and PGV are respectively >450 gal and >75 cm/s. Ten damaging seismic events in the past twelve years are redefined using this new earthquake damage index, with the devastating Chi-Chi earthquake and one non-damaging event as reference earthquakes. This newly proposed index depicts seismic hazard of these earthquakes with higher accuracy when compared to the existing intensity scale in Taiwan region. For further analysis, Japan earthquakes are also plotted as references.

Ng, S.

2012-12-01

373

Solar water heaters in Taiwan  

Microsoft Academic Search

Solar water heater has been commercialized during the last two decades in Taiwan. The government initiated the incentive programs during 1986–1991 and 2000–2004. This created an economic incentive for the end-users. The total area of solar collectors installed was more than one million square meters. The data also show that most of the solar water heaters are mainly used by

K. Chang; T. Lee; K. Chung

2006-01-01

374

Genotoxic Klebsiella pneumoniae in Taiwan  

PubMed Central

Background Colibactin is a nonribosomal peptide-polyketide synthesized by multi-enzyme complexes encoded by the pks gene cluster. Colibactin-producing Escherichia coli have been demonstrated to induce host DNA damage and promote colorectal cancer (CRC) development. In Taiwan, the occurrence of pyogenic liver abscess (PLA) has been suggested to correlate with an increasing risk of CRC, and Klebsiella pneumoniae is the predominant PLA pathogen in Taiwan Methodology/Principal Findings At the asn tRNA loci of the newly sequenced K. pneumoniae 1084 genome, we identified a 208-kb genomic island, KPHPI208, of which a module identical to the E. coli pks colibactin gene cluster was recognized. KPHPI208 consists of eight modules, including the colibactin module and the modules predicted to be involved in integration, conjugation, yersiniabactin production, microcin production, and unknown functions. Transient infection of BALB/c normal liver cells with K. pneumoniae 1084 increased the phosphorylation of histone H2AX, indicating the induction of host DNA damage. Colibactin was required for the genotoxicity of K. pneumoniae 1084, as it was diminished by deletion of clbA gene and restored to the wild type level by trans-complementation with a clbA coding plasmid. Besides, BALB/c mice infected with K. pneumoniae 1084 exhibited enhanced DNA damage in the liver parenchymal cells when compared to the isogenic clbA deletion mutant. By PCR detection, the prevalence of pks-positive K. pneumoniae in Taiwan is 25.6%, which is higher than that reported in Europe (3.5%), and is significantly correlated with K1 type, which predominantly accounted for PLA in Taiwan. Conclusions Our knowledge regarding how bacteria contribute to carcinogenesis has just begun. The identification of genotoxic K. pneumoniae and its genetic components will facilitate future studies to elucidate the molecular basis underlying the link between K. pneumoniae, PLA, and CRC. PMID:24852749

Lai, Yi-Chyi; Lin, Ann-Chi; Chiang, Ming-Ko; Dai, Yu-Han; Hsu, Chih-Chieh; Lu, Min-Chi; Liau, Chun-Yi; Chen, Ying-Tsong

2014-01-01

375

Strong Decoherence  

Microsoft Academic Search

We introduce a condition for the strong decoherence of a set of alternative histories of a closed quantum-mechanical system such as the universe. The condition applies, for a pure initial state, to sets of homogeneous histories that are chains of projections, generally branch-dependent. Strong decoherence implies the consistency of probability sum rules but not every set of consistent or even

Murray Gell-Mann; James B. Hartle

1995-01-01

376

Occupational Neurotoxic Diseases in Taiwan  

PubMed Central

Occupational neurotoxic diseases have become increasingly common in Taiwan due to industrialization. Over the past 40 years, Taiwan has transformed from an agricultural society to an industrial society. The most common neurotoxic diseases also changed from organophosphate poisoning to heavy metal intoxication, and then to organic solvent and semiconductor agent poisoning. The nervous system is particularly vulnerable to toxic agents because of its high metabolic rate. Neurological manifestations may be transient or permanent, and may range from cognitive dysfunction, cerebellar ataxia, Parkinsonism, sensorimotor neuropathy and autonomic dysfunction to neuromuscular junction disorders. This study attempts to provide a review of the major outbreaks of occupational neurotoxins from 1968 to 2012. A total of 16 occupational neurotoxins, including organophosphates, toxic gases, heavy metals, organic solvents, and other toxic chemicals, were reviewed. Peer-reviewed articles related to the electrophysiology, neuroimaging, treatment and long-term follow up of these neurotoxic diseases were also obtained. The heavy metals involved consisted of lead, manganese, organic tin, mercury, arsenic, and thallium. The organic solvents included n-hexane, toluene, mixed solvents and carbon disulfide. Toxic gases such as carbon monoxide, and hydrogen sulfide were also included, along with toxic chemicals including polychlorinated biphenyls, tetramethylammonium hydroxide, organophosphates, and dimethylamine borane. In addition we attempted to correlate these events to the timeline of industrial development in Taiwan. By researching this topic, the hope is that it may help other developing countries to improve industrial hygiene and promote occupational safety and health care during the process of industrialization. PMID:23251841

Liu, Chi-Hung; Huang, Chu-Yun

2012-01-01

377

Coseismic Surface GPS Displacement and Ground Shaking Associated with the 2006 Pingtung Earthquake Doublet, Offshore Southern Taiwan  

E-print Network

-Ching Liu Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan, ROC Received 31 December 2007 ground shaking in great detail, including the first motion direction and the amplitude and arrival time with magnitudes ML = 6.96 and 6.99 occurred only eight minutes apart in time approximate 40 and 33 km

Lee, Jian-Cheng

378

Quantum Einstein's Brownian motion  

E-print Network

Einstein's Brownian motion of a quantum particle in a classical environment is studied via virial and equipartition theorems. The effect of continuous measurement in a strongly dissipative environment is accounted for and a quantum generalization of the classical Einstein law of Brownian motion is obtained. A thermo-quantum Smoluchowski diffusion equation is derived via a generalization of the Madelung quantum hydrodynamics. The latter is applied for description of the quantum tunneling at equilibrium and stationary states as well as of the motion of an electron in metals, i.e. the Smoluchowski-Poisson problem.

R. Tsekov

2010-01-18

379

Applying environmental externalities to US Clean Coal Technologies for Taiwan  

SciTech Connect

During the period 1971 to 1980, electricity consumption in Taiwan increased remarkably at an average rate of 12.2% per year. Despite experiencing a record low in 1982 and 1983, electricity demand returned to double digit growth, reaching 11.6% and 10.2% in 1987 and 1988, respectively, due to a strong economic recovery. In 1988, 71.6 TWh of electricity was produced, 21.1 TWh of which was from coal-fired units (29%). The electricity demand for Taiwan is expected to continue to grow at a very rapid rate during the 1990--2006 time frame. The average load is expected to grow at an annual rate of 5.6% while the peak load is projected to increase at an annual rate of 6.0%. All new coal-fired power plants are expected to comply with government regulations on S0{sub 2}, NO{sub x}, and particulate emissions. Taper reports that all of its proposed coal-fired units will be equipped with modern flue gas emission reduction devices, such as electrostatic precipitators or baghouse filters, flue gas desulfurization and deco{sub x} devices, to reduce the pollutants to their minimum practical levels. New coal-based generation requirements in the sizes needed in Taiwan create an opportunity for several of the Cats currently under demonstration in the United States. Options to be considered are described.

Szpunar, C.B.; Gillette, J.L.

1992-01-01

380

Applying environmental externalities to US Clean Coal Technologies for Taiwan  

SciTech Connect

During the period 1971 to 1980, electricity consumption in Taiwan increased remarkably at an average rate of 12.2% per year. Despite experiencing a record low in 1982 and 1983, electricity demand returned to double digit growth, reaching 11.6% and 10.2% in 1987 and 1988, respectively, due to a strong economic recovery. In 1988, 71.6 TWh of electricity was produced, 21.1 TWh of which was from coal-fired units (29%). The electricity demand for Taiwan is expected to continue to grow at a very rapid rate during the 1990--2006 time frame. The average load is expected to grow at an annual rate of 5.6% while the peak load is projected to increase at an annual rate of 6.0%. All new coal-fired power plants are expected to comply with government regulations on S0{sub 2}, NO{sub x}, and particulate emissions. Taper reports that all of its proposed coal-fired units will be equipped with modern flue gas emission reduction devices, such as electrostatic precipitators or baghouse filters, flue gas desulfurization and deco{sub x} devices, to reduce the pollutants to their minimum practical levels. New coal-based generation requirements in the sizes needed in Taiwan create an opportunity for several of the Cats currently under demonstration in the United States. Options to be considered are described.

Szpunar, C.B.; Gillette, J.L.

1992-09-01

381

Motion Sickness  

MedlinePLUS

... Motion sickness, whether on boats or in planes, cars or amusement rides, can strike anyone. 290229 InteliHealth ... Motion sickness, whether on boats or in planes, cars or amusement rides, can strike anyone. Those who ...

382

Foreign factors in Taiwan's economic transformation  

Microsoft Academic Search

This paper aims to explore the foreign influences on Taiwan's economic transformation over the past 40 years. While exports have always been important in sustaining Taiwan's economic growth, the driving force behind exports has changed from inward investment to outward investment. The analysis carried out is from an international political economy perspective and takes a historical overview. It argues that

Min-Hua Chiang; Bernard Gerbier

2010-01-01

383

Mountain building in Taiwan: A thermokinematic model  

Microsoft Academic Search

The Taiwan mountain belt is classically viewed as a case example of a critical wedge growing essentially by frontal accretion and therefore submitted to distributed shortening. However, a number of observations call for a significant contribution of underplating to the growth of the orogenic wedge. We propose here a new thermokinematic model of the Taiwan mountain belt reconciling existing kinematic,

Martine Simoes; Jean Philippe Avouac; Olivier Beyssac; Bruno Goffé; Kenneth A. Farley; Yue-Gau Chen

2007-01-01

384

Flower Drinking and Masculinity in Taiwan  

Microsoft Academic Search

This study explores the role of the hostess club culture in the creation and maintenance of masculinity in Taiwan. The article focuses on flower drinking (the consumption of alcohol in bars, often integrated with prostitution), which is a common practice in Taiwan. Data were obtained from 58 in-depth interviews with men from a variety of occupations and social backgrounds (mean

Olwen Bedford; Shu-Ling Hwang

2010-01-01

385

The Handy Guide for Foreigners in Taiwan  

E-print Network

Traditional Chinese Medicine 78 Drug Safety 80 Medical Tourism 80 87 Employment and Investment Work Permits and Internet 67 Postal Services 69 Buying Daily Necessities 69 Keeping a Pet 70 Recycling 71 81 Banking in Taiwan 85 Credit Cards 86 Internet Banking 86 97 Studying Foreign Schools 98 Taiwan Education Centers 100

386

Taiwan: meeting the new challenges (engineering education)  

Microsoft Academic Search

The state of engineering education in Taiwan is presented in terms of the number of engineering departments in Taiwanese universities and the number of students graduated from those departments. The basic philosophy of undergraduate engineering education in Taiwan, providing a general-purpose training to most people who want it, is discussed. The manner in which the education system is managed in

Lee Lin-Shan

1992-01-01

387

Engineering characterization of near fault ground motions  

Microsoft Academic Search

Near-fault ground motions are different from ordinary ground motions in that they often contain strong coherent dynamic long period pulses and permanent ground displacements, as expected from seismological theory. The dynamic motions are dominated by a large long period pulse of motion that occurs on the horizontal component perpendicular to the strike of the fault, caused by rupture directivity effects.

Paul G. Somerville

388

76 FR 13982 - Antidumping Duty Order: Polyvinyl Alcohol From Taiwan  

Federal Register 2010, 2011, 2012, 2013

...A-583-841] Antidumping Duty Order: Polyvinyl Alcohol From Taiwan AGENCY: Import Administration...an antidumping duty order on polyvinyl alcohol (PVA) from Taiwan. DATES: Effective...investigation of PVA from Taiwan. See Polyvinyl Alcohol From Taiwan: Final Determination of...

2011-03-15

389

Internationalization or Commodification? A Case Study of Internationalization Practices in Taiwan's Higher Education  

ERIC Educational Resources Information Center

This article examines how commodification and consumerism have sharpened the discourse of internationalization in Taiwan's higher education. Given the strong sense of crisis in the less prestigious universities, this article argues that internationalization is only a means to survive instead of a pursuit of excellence to these universities. This…

Chen, Dorothy I-ru; Lo, William Yat Wai

2013-01-01

390

PROUD TO BE CHINESE: LITTLE LEAGUE BASEBALL AND NATIONAL IDENTITIES IN TAIWAN DURING THE 1970s  

Microsoft Academic Search

Defeated by the communists in 1949, the Chinese Nationalist Party (KMT) sought refuge in Taiwan under the conditions of war and aggression that produced strong defensive nationalism and an intensive struggle for national identification. The KMT faced a dual crisis of legitimacy during the 1970s, both domestically and internationally, after being expelled from the United Nations. The urgency of seeking

Junwei Yu; Alan Bairner

2008-01-01

391

Seasonal variation of microbial ecology in hemlock soil of Tatachia Mountain, Taiwan  

Microsoft Academic Search

Background and Purpose: Forest soil microorganisms and fauna decompose the organic materials, and thus strongly influence the nutrient cycling of the ecosystem. Soil microorganisms also contribute to soil structure and soil fertility. In Taiwan, the microbial distributions of soils have only been determined in acidic soil, inorganic acidic soil, upland soil, alkaline soil and power plant areas. There are few

Shang-Shyng Yang; Shu-Hsien Tsai; Hsiao-Yun Fan; Chiun-Kai Yang; Wei-Lan Hung; Shine-Tsern Cho

2006-01-01

392

Dust Activity during Winter Time in East Asia and Snowfall Obervations and Simulations in Taiwan  

NASA Astrophysics Data System (ADS)

Taiwan has relatively frequent snowfall in mountain during winter among regions of the same latitude. The phenomenon is contributed by Taiwan's unique topography - high and steep mountains, and geographical location - sitting on the route the continental polar air mass travels from its birthplace to the ocean, contribute to this phenomenon. Snow occurence, in addition to the freezing-point temperature, when two requirements are met: sufficient vapor and the condensation nuclei in the air. This study pursues the causes of the snowfall activity in Taiwan, the relations between the East Asian dust aerosol and the snowfall activity in Taiwan, and the impacts the climate changes have on the snowfall activity in Taiwan. In this study, Yushan snowfall activity from 1995~2011 and related atmosphere circulations were examined using SYNOP data, NCEP/DOE reanalysis atmospheric data, the observations of the Central Weather Bureau's Yushan Weather Station and the Taiwan Air Quality Monitoring Network of the Environment Protect Administration, Executive Yuan. To provide a quantitative measure of snowfall events and dust activity, a snowfall activity index (SAI) and the DAI Index by Yu et al. (2010) were defined. The time series of yearly SAI and DAI show that East Asian dust storm activity and Taiwan snowfall marked interannual variations during 1995 ~ 2011. For active years such as 2008, 2010, and 2011, SAI was hundreds of times larger than that for inactive years such as 1996, 1999 and 2003; and DAI in active years such as 2001 and 2002 was several tens of times larger than that in inactive years such as 1997 and 2003. In active years when the EAT (East Asian Trough) was shifted eastward, the strength of WPH (West Pacific High) increased in the south and an anticyclone thus occurred. This anticyclone introduced anomalous southwesterly flows along the southeastern coast of mainland China and over Taiwan, resulting in a wetter-than-normal atmosphere in support of snowfall. Oppositely, for inactive years, drier-than-normal atmosphere appeared and consequently sluggish snowfall seasons followed. A SVD (singular value decomposition) analysis of the Asian synoptic circulation indicated that the connection between the pressure dipoles and the position of EAT is strong in 1998, 1999, 2001, 2002, 2003, 2010, and 2011. It significantly affects both of the snowfall and dust activities. In summary, snowfall active years usually occurred when the East Asian dust storm was inactive. Nevertheless, the snowfall activity increased in Taiwan if there was dust event and the dust aerosol successfully transported to Taiwan. This finding is also demonstrated in the model simulation of this study.

Tsai, L.

2013-12-01

393

Seismicity and Tectonics of the Western Pacific: Izu-Mariana-Caroline and Ryukyu-Taiwan Regions  

Microsoft Academic Search

The hypocenters of about 1000 earthquakes in the Izu-Bonin, Mariana, Palau, Caroline, and ttyukyu-Taiwan regions were relocated by computer, and earthquake mechanism solutions based on the first motions of P, pP, and $ were determined for 26 earthquakes. The spatial distribution and the mechanisms were compared with major tectonic features such as volcanic zones, island arcs, and trenches. Although a

Mamoru Katsumata; Lynn R. Sykes

1969-01-01

394

A model for the termination of the Ryukyu subduction zone against Taiwan: A junction of collision, subduction/separation, and subduction boundaries  

USGS Publications Warehouse

The NW moving Philippine Sea plate (PSP) collides with the Eurasian plate (EUP) in the vicinity of Taiwan, and at the same time, it subducts toward the north along SW Ryukyu. The Ryukyu subduction zone terminates against eastern Taiwan. While the Ryukyu Trench is a linear bathym??trie low about 100 km east of Taiwan, closer to Taiwan, it cannot be clearly identified bathymetrically owing to the deformation related to the collision, making the location of the intersection of the Ryukyu with Taiwan difficult to decipher. We propose a model for this complex of boundaries on the basis of seismicity and 3-D velocity structures. In this model the intersection is placed at the latitude of about 23.7??N, placing the northern part of the Coastal Range on EUP. As PSP gets deeper along the subduction zone it collides with EUP on the Taiwan side only where they are in direct contact. Thus, the Eurasian plate on the Taiwan side is being pushed and compressed by the NW moving Philippine Sea plate, at increasing depth toward the north. Offshore of northeastern Taiwan the wedge-shaped EUP on top of the Ryukyu subducting plate is connected to the EUP on the Ryukyu side and coupled to the NW moving PSP by friction at the plate interface. The two sides of the EUP above the western end of the subduction zone are not subjected to the same forces, and a difference in motions can be expected. The deformation of Taiwan as revealed by continuous GPS measurements, geodetic movement along the east coast of Taiwan, and the formation of the Hoping Basin can be understood in terms of the proposed model. Copyright 2009 by the American Geophysical Union.

Wu, F.T.; Liang, W.-T.; Lee, J.-C.; Benz, H.; Villasenor, A.

2009-01-01

395

Numerical modelling of ground motion in the Taipei Basin: basin and source effects  

NASA Astrophysics Data System (ADS)

The Taipei basin in northern Taiwan is located in a high seismicity region and was affected by several earthquakes in the past (ML = 7.3 on 1909 April 15; ML = 6.8 on 1986 November 15; the Chi-Chi ML = 7.3 earthquake on 1999 September 21 and ML = 6.8 on 2002 March 31). The main characteristic of the Taipei basin is its complex shape with a deep western and shallow eastern part. The uppermost Sungshan formation with its low shear wave velocities (90-200ms-1) is also a distinct feature of the basin. Based on the large data base of earthquake records obtained from the Taiwan Strong Motion Instrumentation Program network, many studies on ground motion within the Taipei basin exist. However, the influence of the various subsurface structures on the observed ground motions as well as the variability of ground motion with respect to earthquake location is not fully understood. We apply a 3-D finite-difference method to simulate wave propagation up to 1Hz for a small earthquake close to the basin in order to resolve these open questions. By varying source and structural parameters, we explore the variability of ground motion. Our study includes a subsurface model that is based on recent studies on the basin structure and on the crustal structure of Taiwan. From our simulations we find a good fit between simulated and observed waveforms and peak ground accelerations for the considered small earthquake near the basin. We also explore the influence of fault plane orientation, hypocentre location, deep basin structure and soft soil surface layers of the Sungshan formation by varying the subsurface structure and earthquake position. Our studies reveal that the basin structure produces an amplification factor of about 4 compared to hard rock conditions. Additionally, the soft soil Sungshan formation produce amplification of a factor of 2. This results in a maximum amplification of the basin structure of about 8, which is in good comparison with amplification values larger than 5 found from the analysis of observed earthquakes. These values clearly exceed the amplification values of about 2-3 obtained when applying standard 1-D site effect analysis. Our simulations for different earthquake positions show that ground motion depends strongly on earthquake location and fault orientation. Therefore, the application of average values of spectral amplification obtained from the analysis of recorded data from distant earthquakes with different azimuths and fault planes may significantly underestimate future ground motions of possible earthquakes on known faults close to the Taipei basin. The simulation of a small earthquake near the Taipei basin presented in this study will help to set up adequate simulation parameters for a possible large earthquake close to the Taipei basin. Such a simulation of a scenario earthquake close to the Taipei basin would allow to significantly improve hazard assessment as no observations of strong earthquakes in the vicinity of the basin exist.

Miksat, J.; Wen, K.-L.; Wenzel, F.; Sokolov, V.; Chen, C.-T.

2010-12-01

396

The Evolution of Education and Training Strategies in Singapore, Taiwan and S. Korea: A Development Model of Skill Formation.  

ERIC Educational Resources Information Center

Examination of the government role in labor force development in Singapore, Taiwan, and South Korean identified strategies and structures enabling the "East Asian Miracle" of economic development, including strong states with high autonomy regarding capital and labor, super-ministries linking institutions, and strong central control of education…

Ashton, D.; Green, F.; Sung, J.; James, D.

2002-01-01

397

Three-Dimensional Tectonic Model of Taiwan  

NASA Astrophysics Data System (ADS)

We built a three-dimensional model of the interactions of the Eurasian plate (EUP) the Philippine Sea plate (PSP) and the collisional orogen, in and around Taiwan. The model is based on the results of comprehensive, milt-prong TAIGER experiments on land and at sea as well as other existing data. The clockwise rotating PSP moves NWW at ~8 cm/year relative to the Taiwan Strait. Under northern Taiwan the northward subducting PSP terminates near the edge of eastern Taiwan and collides with EUP at in increasing depth toward the north. Mountain building due to collision of EUP and PSP tapers off where the PSP goes below about 60 km. The PSP in the asthenosphere continues to advance NWW-ward. In central Taiwan PSP and EUP collide fully, lithosphere against lithosphere in the upper 60 km or so, leading to significant thickening of the crust to about 55 km on the Central Range side and about 35 km on the Coastal Range/Arc side. In between these "roots" a high velocity rise is found. Although a clear, steep dipping high velocity zone under Central Taiwan is detected, it is found not to be associated with seismicity. In southern Taiwan, mountains form over well-defined, seismically active subduction zone. The upper mantle high velocity anomaly appears to be continues with that under central Taiwan, but here an inclined seismic zone is found. In this area the Luzon Arc has not yet encountered the continental shelf - thus arc-continental collision has not yet occurred. The orogeny here may involve inversion of the subducted South China Sea lithosphere, rifted Eurasian continent, and/or escape of continental material from central Taiwan. GPS and Leveling data reflect well the 3-D plate collision model.

Wu, Francis; Kuo-Chen, Hao; McIntosh, kirk

2014-05-01

398

Animating Motion  

NSDL National Science Digital Library

This lesson challenges students to apply their knowledge of object motion by animating sequences of hand-rendered pictures that model a set of physical conditions. The challenges include animating the orbital motion of planets and satellites, the effects of gravity on a falling body, and motions of objects in inertial (moving) frames of reference. The lesson was created by a high school physics teacher to help learners build quantitative reasoning skills in preparation for understanding kinematics.

Latham, Ted

2004-07-16

399

Magical Motion  

NSDL National Science Digital Library

Students watch video clips from the October Sky and Harry Potter and the Sorcerer's Stone movies to see examples of projectile motion. Then they explore the relationships between displacement, velocity and acceleration, and calculate simple projectile motion. The objective of this activity is to articulate concepts related to force and motion through direct immersive interaction based on "The Science Behind Harry Potter" theme. Students' interest is piqued by the use of popular culture in the classroom.

National Science Foundation GK-12 and Research Experience for Teachers (RET) Programs,

400

Instrumental intensity distribution for the Hector Mine, California, and the Chi-Chi, Taiwan, earthquakes: Comparison of two methods  

USGS Publications Warehouse

We compare two methods of seismic-intensity estimation from ground-motion records for the two recent strong earthquakes: the 1999 (M 7.1) Hector Mine, California, and the 1999 (M 7.6) Chi-Chi, Taiwan. The first technique utilizes the peak ground acceleration (PGA) and velocity (PGV), and it is used for rapid generation of the instrumental intensity map in California. The other method is based on the revised relationships between intensity and Fourier amplitude spectrum (FAS). The results of using the methods are compared with independently observed data and between the estimations from the records. For the case of the Hector Mine earthquake, the calculated intensities in general agree with the observed values. For the case of the Chi-Chi earthquake, the areas of maximum calculated intensity correspond to the areas of the greatest damage and highest number of fatalities. However, the FAS method producees higher-intensity values than those of the peak amplitude method. The specific features of ground-motion excitation during the large, shallow, thrust earthquake may be considered a reason for the discrepancy. The use of PGA and PGV is simple; however, the use of FAS provides a natural consideration of site amplification by means of generalized or site-specific spectral ratios. Because the calculation of seismic-intensity maps requires rapid processing of data from a large network, it is very practical to generate a "first-order" map from the recorded peak motions. Then, a "second-order" map may be compiled using an amplitude-spectra method on the basis of available records and numerical modeling of the site-dependent spectra for the regions of sparse station spacing.

Sokolov, V.; Wald, D. J.

2002-01-01

401

A Study of Seismicity and Subsurface Structures by a Temporary Seismic Network in Northwestern Taiwan  

NASA Astrophysics Data System (ADS)

The seismicity is low in northwestern Taiwan recently. However, recent studies found special geological characteristics in this area. Besides, many important facilities, and big cities are in this area. Significant shaking intensities were recorded at strong motion stations in the Hsinchu area during the 1999 Chi-Chi earthquake. The disastrous Hsinchu-Taichung earthquake in 1935 occurred in the southern part of this area. Thus, recurrence of potential large earthquakes in this area becomes an important topic. In response, the seismicity and subsurface structures are analyzed in this study. A temporary seismic network consisting of ten seismic stations was deployed in Taoyuan, Hsinchu and Miaoli counties in northwestern Taiwan since January 2001. Each station has one triaxial accelerograph, three external one-component velocity sensors, global positioning system for timing, and a data storage device. Seismic records with absolute timing are critical to obtain accurate earthquake locations. Dense station distribution is necessary to locate earthquakes of lower magnitude from clear seismic signals recorded locally. Based on careful considerations of available instruments and recording sites, the stations were deployed uniformly in the study area. In this study, the arrival time data of the temporary seismic network and CWBSN are combined to locate earthquake. Two dense earthquake clusters in the study area were relocated to compare with several geological cross sections. In order to study the regional stress patterns, numerous focal mechanisms were determined by waveform inversion. By combining the temporary seismic network and CWBSN data, the results of earthquake location show significant convergent in focal depths by adding of near-source arrival time data. Most of the hypocenters are located shallower than 15 km at depth. Relocation of the two dense clusters using the JHD and DD methods was able to remove systematic bias due to one-dimensional velocity model. The events were shifted toward northwest in the horizontal direction and became more tightly clustered at depth from 5 to 10 km. The station corrections of JHD reflected the difference in geology of the northwest and southeast parts of the study area. It is also consistent with distinct topographic features. By comparing the relocated events with several geological cross sections, we found that the seismicity and subsurface structures are related. To determine the focal mechanisms by waveform inversion, we used the acceleration records. The acceleration records of individual stations with three-component sensors are doubly integrated to get displacement waveforms. Then the focal mechanisms are determined by waveform inversion. In total, 88 focal mechanisms were determined with local magnitudes from 1.35 to 3.33. The widespread presences of varying types of focal mechanisms imply that the microearthquakes might be associated with many subfaults.

Lee, C.; Tsai, Y.; Huang, B.

2005-12-01

402

[The medical autonomy of elderly in taiwan].  

PubMed

The elderly population is increasing rapidly in Taiwan. With the average life expectancy on the rise, the elderly have become major consumers of healthcare products and services. Factors that influence respect for autonomy, a core value of medical ethics, may be related to family, society, and the medical culture. Especially in patients who are already elderly, aging causes declines in physical, mental and societal capacities. Practicing a respect for patient autonomy is particularly challenging for healthcare professionals in Taiwan due the unique culture background of elderly Taiwanese patients. This article reviews and integrates the literature related to the issue of patient autonomy and elaborates on medical decision-making among elderly patients in Taiwan in the contexts of: the disadvantages faced by the elderly, the background of Chinese culture, and the current medical decision-making environment. A few suggestions are proposed to help preserve the medical-decision-making autonomy of elderly patients in Taiwan. PMID:25271030

Chen, Kai-Li; Chen, Ching-Huey

2014-10-01

403

Taiwan: Facing the future with nuclear power  

SciTech Connect

The republic of China on Taiwan is located approximately 100 miles off the southeast coast of mainland China, between Japan and the Philippines, and has an area of 13,970 square miles. The island nation has a population exceeding twenty million people, with over five million living in the capital of Taipei, making Taiwan the second most densely populated country in the world. The country also has one of the world`s fastest growing economies, with major industries that include electronics, textiles, food processing, chemicals and plastics. Annual growth of Taiwan`s gross national product (GNP) has averaged more than 7 percent for the past several years, and the small island is now the twelfth largest trading nation in the world, with a GNP exceeding US$200 billion.

NONE

1994-07-01

404

(20102011) National Taiwan University, Visiting Student Program  

E-print Network

additional restrictions Visiting students will be offered Chinese language courses on a feepaying basis (20102011) National Taiwan University, Visiting Student Program Dates: Semester 1 December 1st) NTU's Visiting Student Program is a feepaying program where students register

Wu, Yih-Min