Earthquakes duration

Nature of climate. Consider seasonal and daily temperature variations, dust, fog, tornados, hurricanes, earthquakes. Define duration of conditions for design. Determine from U.S. Weather Bureau yearly statistics for above, as well as rainfall. Establish if conditions for earthquakes, hurricanes prevail. For stormy conditions, structural design for 100 miles per hour winds usually sufficient. For hurricanes, winds of 125 miles per hour may be design basis. 

The allowable stress for occasional loads of short duration, such as surge, extreme wind, or earthquake, may be taken as the strength reduction factor times 90% of the yield strength at temperature times Mj for materials with ductile behavior. This yield strength shall be as listed in ASME BPV Code Section II, Part D, Table Y-l (ensure materials are suitable for hydrogen service see API 941), or determined in accordance with para. 

Disasters are frequently categorized based on their onset, impact, and duration. For example, earthquakes and tornadoes are rapid-onset events—short durations but with a sudden impact on communities. Hurricanes and volcanic eruptions have a sudden impact on a community however, frequently advance warnings are issued enabling planners to implement evacuation and early response plans. A bioterrorism attack may be... 

The duration of ocean storms is significantly longer than that of earthquake cyclic loadings. 

DBE-5 is an earthquake which trips the HTS. The duration of the earthquake is too short for any transient thermal effects to develop in the core. Consequently, during the first phase of the event, seismic loads are. superimposed on the normal operating thermal-irradiation loads. The core must withstand the combination of these loads and retain its essential safety functions which are to maintain a coolable geometry and allow control rod insertion. These functions may be impaired if 1) the dowels which align the graphite elements within the core columns shear off, or 2) the elements break into two or more pieces. 

Chang, F.K., Krinitzsky, E.L. (1977). Duration, spectral content and predominant period of strong motion earthquake records from Western United States. Miscellaneous paper 5-73-1, U.S. Army Corps Engineers Waterways Experiment Station Vicksburg, Missipppi. 

The hazards due to seismicity include the possibility of a structure being severed by fault displacement but a much more likely event is damage due to shaking (Fig. 8.4). The destruction wrought by an earthquake depends on many factors. Of prime importance are the magnitude of the event, its duration and the response of buildings and other elements of the infrastructure. In addition, other hazards such as landslides, floods, subsidence, tsunamis and secondary earthquakes may be triggered by a seismic event (Khazai and Sitar, 2004),... 

Slightly felt indoors. Hanging objects swing. Vibration like passing of light trucks. Duration estimated. May not be recognized as earthquake. 

Many seismologists believe that the duration of an earthquake is the most important factor as far as damage or failure of structures, soils and slopes are concerned. Buildings may remain... 

To obtain the dynamic response (according to Sect. 8.3.3) of the structure, four different types of earthquakes (El Centro 1940, Parkfield 2004, Ulcinj 1979, Petrovac 1979) with a maximum input acceleration of 0.36g have been applied. This set of records was chosen in order to investigate nonlinear structural response to excitations with different frequency content and duration. The results (Tables 8.8 and 8.9) show that, under acceleration of 0.36, the structure behaves in accordance with the designed seismic safety criteria (Sect. 8.3.4). 

A nonlinear path-dependent constitutive model for the soil mainly depends on the shear stress-shear strain relationship, which is extended to three-dimensional generic conditions and assumed to follow Masing s rule for the soil hysteresis. The soil is idealized as an assembly of a finite number of elasto-perfectly plastic elements connected in parallel as shown in Fig. 25.3 (Okhovat et al. 2009, Mohammed and Maekawa 2012 Mohammed et al. 2012a). The nonlinear behavior of the soil system in liquefaction is assumed as in undrained state, since its drainage takes much longer than the duration of an earthquake (Towhata 2008). The soil undrained behavior is shown in Fig. 25.4. 

For the seismic design of SSCs, external events such as floods or fires assumed to occur at the site as a consequence of an earthquake should be taken into account. They should be defined on the basis of probabilistic considerations. These loadings as a consequence of an earthquake should be combined with either SL-1 or SL-2 loadings, with due account taken of event timing and duration. 

If random vibration or multifrequency input motion is used, appropriate procedures should be followed. The duration of the input motion should be decided on the basis of the antidpated duration of the earthquake [2]. 

Duration The length of time ground motion occurs during an earthquake. 

Source Parameters A series of earthquake characteristics, including distance, duration, energy, and the types of waves that occur. 

In the mid-eighteenth century, however, the British Isles experienced a series of severe earthquakes, which created a tsunami that destroyed Lisbon, Portugal, killing tens of thousands of people. Scientists quickly developed an interest in cataloging and understanding seismic events. In the early nineteenth century, Scottish physicist and glaciologist James D. Forbes invented the inverted pendulum seismometer, which gauged not only the severity of an earthquake but also its duration. 

Magnitude may be based on a number of key lac-tors (or source parameters), including duration, distance to the epicenter and hypocenter, the size and speed of the surface waves, the amount of energy (known as the stress drop) that is released fi-om the hypocenter, P and S waves, and the directions in which surface waves move (the wrave props tion path). Analyzing an earthquake s ms nitude provides an accurate profile of the quake and the conditions that caused it. 

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