ABSTRACT The ground shaking induces vibrations in the structure and the resulting deformations can cause significant damage and possibly collapse of the structure. Dynamic analysis can be used to determine from the acceleration records of ground shaking the maximum accelerations, velocities and displacements imposed on various elements of a structure. The ground shaking can result in deformations of the ground that cause damage. One example is landslides in sloping ground. Another is relative movement along and across surface fault lines and uplift, each of which can be up to several meters.
In the period of 15 months after the earthquake in a careful analysis that compared the Hayward fault and that of 1906 earthquake; displays that there were horizontal to the fault in San Andreas. The report showed that the coseismic horizontal displacements are parallel to the fault of San Andreas with opposite sides of the fault that moved in opposite directions observed in the lateral offsets. The geologist Thatcher analyzed the information from the surveying records of the Commission and refined the distribution of the slip. The main principles that drive the knowledge and understanding of the 1906 earthquake come from the seismic hazard assessment principles. The principles explain that the earthquakes come under the continuous and long active faults from past earthquakes that had associated style offsets in faults.
Subduction zones can create beautiful landscapes such as mountains; however, they are also dangerous regions. Subduction zones occur because one of the plates that collide with other, in convergent plate boundaries, is of higher density. Hence it sinks into the earth back to the mantle (lecture 3, slide 24-26). When such phenomenon occurs, natural hazards such as earthquakes or tsunamis would occur, making these regions dangerous. Nevertheless, it does not limit traveling.
Sunda Arc is convergence for Indo-Australia and the volcanism of which associated with subduction of Indo-Australian plate beneath Eurasian plate at rate of approximately 6 to 7 cm/year (Hall, R., 2009). The uppermost crust setting surrounding Merapi Volcano evidenced by isotropic and anisotropic anomalies in the uppermost crust from tomogram (Koulakov, 2009). Tomographic expression clarify an inclined low-velocity anomaly associates with the seismicity cluster at the depth 100 km with the active volcanoes on the surface. This anomaly as path of fluids which released from the slab due to phase transitions. These fluids originated from active melting in the mantle segment and in the crust beneath the
The sudden impact of gases at high pressures on the wall of blast hole causes the shock wave to be transmitted into the rock mass. The outgoing shock wave generates the fracture in the surrounding rocks, provided the intensity of the stress is greater than the dynamic compressive strength of rock (Hagan, 1973). It also develops radial fractures due to tangential and tensile stresses (Johansson and Persson, 1970). Upon meeting an open joint or a free face, the compressive stress wave gets reflected and spalling occurs if the intensity of the tensile wave exceeds the dynamic tensile strength of the rock (Hino, 1956; Duvall and Atchison, 1957). The reflections of the compressive wave generate tensile and shear waves, which may propagate through pre-existing cracks and further widens them apart (Fourney, 1993) due to the phase difference between the two wave types.
The hasty emancipation of energy generates seismic waves that surges throughout the earth. Researchers use the diverse speeds of seismic waves to pinpoint the epicenter (the point on the surface directly above where the tremor initiated) of earthquakes. Seismometers are used to measure the magnitude of earthquakes. It is improbable to undergo the enormousness of a level three earthquake. The damage caused by earthquakes also depends on their depth and fault type.
Nonlinear static procedures are now widely used in engineering practice to predict seismic demands in building structures. The simplified versions of NSP based on lateral load capacity such as those recommended in ATC-40 and FEMA-356 have well-documented limitations in terms of their inability to account for higher mode effects and modal variation resulting from inelastic behaviour. Results from the analytical study indicate that peak response measures such as inter-story drift and component plastic rotations more consistently than the other NSP’s investigated in the
These blasts reflected positive pressures are applied to the front side of building in the form of blast force. These blast forces can be obtained by multiplying the pressures with the contributing area of each node. A sample calculation for forces acting on the nodes due to blast weight of 100kg at standoff distance of 20m is shown below, i) For node no 83; Positive pressure= 137.3 kPa Blast force P83 = 0.1373x0.25x1000= 34.32kN ii) For node no 86; Positive pressure = 80.8 kPa Blast force P86 = 0.0808x0.5x1000 = 40.4 kN iii) For node no 89; Positive pressure = 56.1 kPa Blast force P89 = 0.0561x0.5x1000 = 28.50kN iv) For node no 80; Positive pressure = 42.5 kPa Blast force P80 = 0.0425x0.25x1000 = 10.63
Volcanic terrain has natural resources like building materials, geothermal energy, and tourism opportunities, which attract populations of people to live by them [Smith, pg.176]. The region around a volcano is highly dangerous due to many volcanic hazards, such as lahars, tephra, and pyroclastic flows. Lahars are a mix of water and muddy debris that flows violently downhill [Kumagai]. These lahars can travel a distance of tens of miles at speeds over 50 mph, destroying bridges, houses, and anything in their pathway [Kumagai]. Tephra is a mix of coarse debris and ash that is shot up in the air when a volcano erupts.
The type of earthquake depends on the region where it occurs and the geological make-up of that region. The most common are tectonic earthquakes. The earthquake comes different in waves forms mainly either in body waves and surface waves. Body waves consist of p-waves(primary or compressional waves) which is like sound waves and s waves (secondary, shear, sideways or transverse waves) travels like ripples on waters. Surface waves resembling water waves containing Love waves move like a snake and a Rayleigh wave rolls along the ground just like a wave rolls across a lake or