List Of Active Fault Lines In The Philippines




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GEOGRAPHY


In geology, a fault is a planar fracture or discontinuity in a volume of rock, across which there has been significant displacement. Large faults within the Earth's crust result from the action of tectonic forces. Energy release associated with rapid movement on active faults is the cause of most earthquakes, such as occurs on the San Andreas FaultCalifornia.

fault line is the surface trace of a fault, the line of intersection between the fault plane and the Earth's surface.[1]

Since faults do not usually consist of a single, clean fracture, geologists use the term fault zone when referring to the zone of complex deformation associated with the fault plane.

The two sides of a non-vertical fault are known as the hanging wall and footwall. By definition, the hanging wall occurs above the fault plane and the footwall all occurs below the fault.[2] This terminology comes from mining: when working a tabular ore body, the miner stood with the footwall under his feet and with the hanging wall hanging above him.[3]

List Of Active Fault Lines In The Philippines

  1. Marikina Valley Fault (Montalban, San Mateo, Marikina, Pasig, Taguig, Muntinlupa, San Pedro, Binan, Carmona, Santa Rosa, Calamba, Tagaytay, Oriental Mindoro)

  2. Western Philippine Fault (Luzon Sea, Mindoro Strait, Panay Gulf, Sulu Sea)

  3. Eastern Philippine Fault (Philippine Sea)

  4. Southern of Mindanao Fault (Moro Gulf, Celebes Sea)

  5. Central Philippine Fault (Entire Ilocos Norte, Aurora, Quezon, Masbate, Eastern Leyte, Southern Leyte, Agusan Del Norte, Agusan Del Sur, Davao del Norte)

Of these, the MARIKINA VALLEY FAULT poses the greatest danger because it cuts through all the modern and progressive portions of Manila such as Eastwood, Rockwell, Ortigas Center, Bonifacio Global City, Ayala Center, and Alabang. Also, the PhiVolcs people have warned that this fault line can move anytime because it is already “11 years late” for its movement.

*The earthquake that destroyed Guinsaugon is the Central Philippine Fault
*The 1990 earthquake that destroyed Central Luzon and Baguio is also the Central Philippine Fault.

An equinox occurs twice a year, when the tilt of theEarth's axis is inclined neither away from nor towards the Sun, the center of the Sun being in the same plane as the Earth's equator. The term equinox can also be used in a broader sense, meaning the date when such a passage happens. The name "equinox" is derived from the Latin aequus (equal) and nox(night), because around the equinox, the night and day have approximately equal length.

At an equinox, the Sun is at one of two opposite points on the celestial sphere where the celestial equator (i.e. declination 0) and ecliptic intersect. These points of intersection are called equinoctial points: classically, the vernal point and theautumnal point. By extension, the term equinoxmay denote an equinoctial point.

An equinox happens each year at two specific moments in time (rather than two whole days), when there is a location (the subsolar point) on the Earth's equator, where the center of the Sun can be observed to be vertically overhead, occurring around March 20/21 and September 22/23 each year.

Although the word equinox is often understood to mean "equal [day and] night," this is not strictly true. For most locations on earth, there are two distinct identifiable days per year when the length of day and night are closest to being equal; those days are referred to as the "equiluxes" to distinguish them from the equinoxes. Equinoxes are points in time, but equiluxes are days. By convention, equiluxes are the days where sunrise and sunset are closest to being exactly 12 hours apart.[2][3]

Names

  • Vernal equinox and autumnal equinox: these classical names are direct derivatives of Latin (ver =spring and autumnus = autumn).

  • March equinox and September equinox: a usage becoming the preferred standard by technical writers choosing to avoid Northern Hemisphere bias (implied by assuming that March is in the springtime and September is autumnal—true for those in the Northern Hemisphere but exactly opposite in the Southern Hemisphere).

  • Northward equinox and southward equinox: names referring to the apparent motion of the Sun at the times of the equinox.

  • Vernal point and autumnal point are the points on the celestial sphere where the Sun is located on the vernal equinox and autumnal equinoxrespectively (again, the seasonal attribution is that of the Northern Hemisphere).

  • First point (or cuspof Aries and first point ofLibra are names used by navigators andastrologersNavigational ephemeris tables record the geographic position of the First Point of Aries as the reference for position of navigational stars. Due to the precession of the equinoxes, the astrological signs of the tropical zodiac where these equinoxes are located no longer correspond with the actual constellations once ascribed to them. The equinoxes are currently in the constellations of Pisces and Virgo. However, modern tropical astrologers assert that the tropical zodiac, and thus 0º degrees Aries, always begins at the Vernal Equinox. Such modern astrologers see the zodiacal signs as 30º segments of the tropical zodiac, always beginning with the Spring equinoctial point, so that the astrological zodiac has no relation to the stars, there being therefore no discrepancy due to precession.



  • EnchantedLearning.com
    The Seasons and Axis Tilt



  • http://www.enchantedlearning.com/egifs/earthseasons.gif


  • The Earth's seasons are not caused by the differences in the distance from the Sun throughout the year (these differences are extremely small). The seasons are the result of the tilt of the Earth's axis.


  • The Earth's axis is tilted from perpendicular to the plane of the ecliptic by 23.45°. This tilting is what gives us the four seasons of the year - spring, summer, autumn (fall) and winter. Since the axis is tilted, different parts of the globe are oriented towards the Sun at different times of the year.

  • Summer is warmer than winter (in each hemisphere) because the Sun's rays hit the Earth at a more direct angle during summer than during winter and also because the days are much longer than the nights during the summer. During the winter, the Sun's rays hit the Earth at an extreme angle, and the days are very short. These effects are due to the tilt of the Earth's axis.

  • Solstices
    The solstices are days when the 
    Sun reaches its farthest northern and southern declinations. The winter solstice occurs on December 21 or 22 and marks the beginning of winter (this is the shortest day of the year). The summer solstice occurs on June 21 and marks the beginning of summer (this is the longest day of the year).

  • Equinoxes
    Equinoxes are days in which day and night are of equal duration. The two yearly equinoxes occur when the Sun crosses the celestial equator.

  • The vernal equinox occurs in late March (this is the beginning of spring in the Northern Hemisphere and the beginning of fall in the Southern Hemisphere); the autumnal equinox occurs in late September (this is the beginning of fall in the Northern Hemisphere and the beginning of spring in the Southern Hemisphere)

The earths axis

Earth's axis is the imaginary line which goes through the north and south poles and around which Earth spins. It is inclined 66.5 degrees from Earth's orbital plane,1 which means that it is tilted 23.5 degrees from a vertical 90 degrees. 

Generally, an axis is any imaginary or physical line that prescribes an object's movement. A taut string that goes through the center of a spinning ball would be an example of a physical axis. The string, as the axis, would represent the part of the ball that is not really moving or that is moving the least. 

An axis also includes the point that is known as the center of gravity.

Note: There are comments associated with this question. See the discussion page to add to the conversation.
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