tabernacle

i was on the train today and i noticed the girl standing in front of me had a sketchpad and a pencil. she was, in fact, drawing the people on the train. that's so cool! i wonder how she could do that. i mean, the train's moving, the train's noisy, people are moving, people are getting off, people are getting on. everything around her keeps changing. maybe she was drawing a video clip.

there was a hysterical lady at the city hall mrt station. she was scary! she was carrying a baby and her husband (i think) was trying to pacify her or something. she kept wailing/screaming/crying. the baby was sleeping soundly despite all the sound around him/her.

i saw the artwork display at the esplanade jendela today. omg, i recognise some of them! i've seen them in the rjc art room before, when the artists were still working on them. i think it's so cool to watch the making of an artwork, and then finally see it at an exhibition. wow it must be even better to be the one who was painting the picture, and submitting it for the competition, and having it showcased! today's so arty farty!

i was at tiong bahru market and i had the dessert yay. mr tham emailed us some examination tips and it's amazing how he's always so cheery.

remember how easy it can be to construct a memory? it's so scary. nowadays, when i 'recall' something, i have to try very hard to determine whether it is a real memory or something that i've constructed out of nothing. maybe in the exact same way, i could de-construct certain memories.

can't finish lithology 2 today. lithology 1 is too heavy. i'll revise now (and here)!

lithology 1

the theory of continental drift has five supporting evidences:
1. palaeomagnetic evidence
2. palaeoclimatic evidence
3. palaeontological evidence
4. continental refits
5. stratigraphy matches

the theory of plate tectonics is supported by two main ideas: the sea floor spreading and subduction hypotheses. the sea floor spreading hypothesis has five supporting evidences:
1. pattern of magnetism
2. pattern of sedimentation
3. flow of geothermal heat
4. distribution of seismic activity
5. dating of volcanic activity

assuming that the earth is not expanding, by principle of conservation, land must be destroyed somewhere, since land is being created at mid-ocean ridges. thus, trenches are theorised to be sites of land destruction. the subduction hypothesis has three supporting evidences:
1. distribution of earthquake foci
2. flow of geothermal heat
3. distribution of seismic activity

plate movements give rise to three different kinds of plate boundaries: divergent, convergent and transform.

at divergent plate boundaries, rifting is common. features of rift valleys include horsts and grabens, mountain ranges and basins, scarp faults and step faults, freshwater and soda lakes, and volcanoes. examples include the east african rift valley and rhine rift valley. after extremely long periods of time, rift valleys will develop into mid-ocean ridges.

at continental-oceanic convergent plate boundaries, continental volcanic arcs can be formed if magma from the subducting oceanic plate makes its way to the surface of the earth. otherwise, they solidify underground and become exposed after weathering. these are called batholiths. such features can be found at the andes mountains.

at oceanic-oceanic convergent plate boundaries, volcanic island arcs will form. this occurs as one oceanic plate subducts under the other. the lava that results has unsually higher amounts of potassium oxide, which is attributed to the partial melting of the upper mantle under cool and moist conditions. examples of volcanic island arcs include the aleutians.

at continental-continental convergent plate boundaries, fold mountains will result. since neither plate can subduct, they force material, in between them, upwards. the himalayas was formed when the indo-australian plate collided into the eurasian plate.

at transform plate boundaries, land is conserved. these plate boundaries result in the strongest earthquakes, especially when elastic energy between adjacent plates is not released periodically, but accumulated over time. the san andreas fault is an example. features found here include offset drainage systems and elongated ponds.

extrusive volcanism occurs when magma emerges onto earth's surface, becoming lava. three types of magma: basaltic (fluid), andesitic, and rhyolitic (viscous). three types of lava flow: pahoehoe, aa, and pillow lava. different features result from different kinds of lava, due to difference in locations. these include shield volcanoes (mauna loa), stratovolcanoes (mount st helens), cinder cones (paricutin), calderas (wizard island) and basalt plateaus (deccan traps).

during volcanic eruptions, several things happen. these include ash flow/fall, bombs and blocks, lava flows, nuee ardentes, and lahars. those that kill are usually nuee ardentes and lahars. case study for nuee ardente: 1902 mount pelee. case study for lahar: 1985 armero.

volcanic hazard management. the behaviour of a volcano can be monitored (example: sakurajima). french geologist bernard chouet developed a method, involving studying seismic waves from the volcano, to predict eruptions. 1995-7's montserrat eruptions showed a failure at volcanic prediction. 1991's pinatubo eruption showed a success at predicting and mitigating the volcanic hazards. tiltmeters can be used to detect change of slope angle, which indicate the possibility of magma building up inside a volcano and thus causing bulging.

evacuation is always a problem. if it's not the infrastructure (example: indonesia), it's the people (example: 2006 merapi eruptions). 1985 armero can be used to illustrate this as well. citizen confidence in planners and economic effects play a part in evacuation planning (and implementing).

earthquakes result from earth movements. they are measured by the mercalli scale for intensity and the richter scale for magnitude. factors which affect the effects of earthquakes include magnitude, depth and location, geology (soil structure and condition), distance, time of day, construction quality and human preparedness.

effects include tsunamis (2004 indian ocean), sloshing, liquefaction (1985 mexico), fires (1923 tokyo, 1906 san francisco), property damage and fluctuation in underground hydrology.

earthquakes can be predicted by using tiltmeters, monitoring seismic activity, observing recurrence intervals and foreshocks. change in animal behaviour can be an indicator, as exemplified by the 1975 haicheng example.

existing buildings can be retrofitted to withstand earthquake shocks, like what is being done to the golden gate bridge. new buildings could be built according to strict guidelines. human preparedness can be trained via drills, as is the case in japanese schools. inducing minor quakes by lubricating faults with water can help reduce storage of elastic energy, and hence stresses. warning systems can be built, like the hawaiian tsunami warning centre. however, indonesia's warning system is inadequate, as shown by the tsunami in java in 2006.

delivery of aid for earthquake victims can be difficult especially in remote areas such as kashmir. the poor infrastructure coupled by cold weather made it difficult for rescue workers to deliver aid after the 2005 kashmir earthquake. other problems like corruption and uneven distribution can be seen in cases like the 2006 indian ocean tsunami.

-fin