Parameter sensitivity analyses in seismic hazard

1996 ◽  
Vol 9 (4) ◽  
pp. 629-634
Author(s):  
Jian Wang ◽  
Meng-Tan Gao
2010 ◽  
Vol 37 (4) ◽  
pp. 562-575 ◽  
Author(s):  
K. Goda ◽  
H. P. Hong ◽  
G. M. Atkinson

This study provides a preliminary assessment of the impact of new seismological information on the existing seismic hazard model, as implemented in the 2005 National building code of Canada (NBCC); this seismic hazard model was actually developed in the early 1990s, and thus there is significant new information available in the literature since then. A reassessment of seismic hazard is carried out by updating magnitude-recurrence relations based on the earthquake catalog up to the end of 2006, including conversion of all earthquake magnitudes to a homogenous moment magnitude scale. The recent ground-motion prediction equations, which update the knowledge base used in the 2005 NBCC, are also used. Focusing on Vancouver and Victoria, sensitivity analyses are carried out to investigate both individual and combined impacts of these updates on the uniform hazard spectra. The proposed model can be used as a guide to the direction in which future seismic hazard models for western Canada may move.


Author(s):  
Qihao Wu ◽  
Min Zhang ◽  
Tian’en Yang ◽  
Nuoya Xu ◽  
Junrong Wang ◽  
...  

Abstract This paper presents parameter sensitivity analysis for a FPSO numerical model updating. Generally, model test data are considered a better presentation of physical phenomena than its numerical counterpart. To minimize the discrepancy, model updating is of pragmatically importance. Model updating of a certain FPSO can be achieved by specific steps. In each step, the required properties of numerical model and test results are matched by means of tuning of the related parameters. To avoid inefficiency and physical meaning loss resulting from large modification of parameters which are insensitive to objective properties, parameter sensitivity analyses using the direct method are conducted in this paper. The investigated parameters mainly are the FPSO’s mooring line length, mooring line mass per unit length, mooring line cross-sectional area, fairlead position, FPSO hydrostatic stiffness, FPSO mass properties, linear and quadratic damping coefficients. According to the different stages of FPSO model updating, the objective functions are set to be the FPSO’s mooring line pretension, mooring system horizontal restoring force, the natural periods of the FPSO’s 6 degree of freedom motions and the standard deviation of motion response spectra under irregular waves.


1984 ◽  
Vol 74 (6) ◽  
pp. 2593-2611
Author(s):  
T. Anagnos ◽  
A. S. Kiremidjian

Abstract Recent geophysical studies have indicated that an earthquake recurrence interval and the size of the preceding event are positively correlated. This observation is the basis for the deterministic time-predictable recurrence model of Shimazaki and Nakata. Using the basic assumptions of the time-predictable recurrence model, we develop a stochastic model of earthquake occurrence that incorporates temporal dependence. This paper discusses the formulation of the model and the effect of including temporal dependence. Hazard estimates for a section of the San Andreas fault near Parkfield, where data has suggested time-predictable behavior, are obtained for illustrative purposes. Comparisons are made with the Poisson model. Results indicate that currently used Poisson models may give lower estimates of the seismic hazard when there has been a seismic gap. Of the various sensitivity analyses performed, it is observed that slip rate has the largest effect on exceedence probabilites computed from the stochastic time-predictable model. Therefore, accurate determinations of slip rates (both seismic and aseismic) can substantially reduce the uncertainty in seismic hazard estimates.


2017 ◽  
Author(s):  
Vishal Singh ◽  
Manish Kumar Goyal ◽  
Rao Y. Surampalli ◽  
Francisco Munoz-Arriola

Abstract. The present work proposes to improve estimates of how much streamflow is generated by snow in the watersheds of the steep Himalayas. Half of the earth’s glacial catchments in nonpolar areas are in the Himalayas, and they generate almost a third of the streamflows in India. In River catchments with glacier presence in the region, temporal variability in streamflow generation and the associated distribution of accumulated snow illustrate how changes in snowmelt and precipitation can affect water supplies to a growing population of 1.3 billion people. Estimations of snowpack and snowmelt in watersheds are critical for understanding streamflow generation and sources of catchments. However, estimating precipitation and snow accumulation is constrained by the difficulties complex terrain poses to data collection. The primary objective of this study is to assess the role of elevations in the computation of snowfall (snowpack) and snowmelt in sub-catchments. The study area is the Satluj River Catchment (up to Kasol gauge) with moderate (e.g., 526 m) to very high elevations (e.g., 7429 m) dominated by snow covers and glaciers. The Satluj River Catchment was divided into 14 sub-catchments. Snowpack and snowmelt variations in the sub-catchments in both historical and projected near-term (2011–2130) periods were analyzed using observed and Global Circulation Model (GCM) data sets. Both hydrological scenarios used elevation bands and parameter-sensitivity analyses built in the Soil Water Assessment Tool (SWAT) model. For model calibration/validation and parameter sensitivity analysis, an advanced optimization method — namely, Sequential Uncertainty Fitting (SUFI2) approach was used with multiple hydrological parameters. Among all parameters, the curve number (CN2) was found significantly sensitive for computations. The snowmelt hydrological parameters such as snowmelt factor maximum (SMFMX) and snow coverage (SNO50COV) significantly affected objective functions such as R2 and NSE during the model optimization process. The computed snowpack and snowmelt were found highly variable over the Himalayan sub-catchments as also reported by previous researchers in other regions. The magnitude of snowpack change consistently decreases across all the sub-catchments of the Satluj River Catchment (varying between 4 % and 42 %). The highest percentage of changes in snowpack was observed over high-elevation subcatchments.


2020 ◽  
Vol 32 ◽  
pp. 101696
Author(s):  
Ruijie Zhao ◽  
Jiadong Xie ◽  
Hejing Wen ◽  
Fei Wang ◽  
Jianhong Yang ◽  
...  

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