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2022 Luzon Earthquake
On July 27, 2022, at 8:43:24 a.m. ( PHT), an earthquake struck the island of Luzon in the Philippines. The earthquake had a magnitude of 7.0 , with an epicenter in Abra province. Eleven people were reported dead and 615 were injured. At least 35,798 homes, schools and other buildings were damaged or destroyed, resulting in ₱ (US$) worth of damage. Earthquake The tectonics of the northern Philippines and around the island of Luzon are complex. Luzon is bounded to the east and west by subduction zones. In the southern part of Luzon, the subduction zone is located east of the island along the Philippine Trench, where the Philippine Sea Plate subducts westward beneath the Sunda Plate. In northern Luzon, where the July 27 earthquake occurred, the subduction zone location and direction changes, with another trench (Manila Trench) located west of Luzon and the Sunda Plate subducts eastward beneath the Philippine Sea Plate. The complexity of plate tectonics on and around Luz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philippine Standard Time
Philippine Standard Time (PST or PhST; fil, Pamantayang Oras ng Pilipinas), also known as Philippine Time (PHT), is the official name for the time zone used in the Philippines. The country only uses one time zone, at an offset of UTC+08:00, but has used daylight saving time for brief periods in the 20th century. Geographic details Geographically, the Philippines lies and 126°34′ east of the Prime Meridian, and is physically located within the UTC+08:00 time zone. Philippine Standard Time is maintained by the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA). The Philippines shares the same time zone with China, Taiwan, Hong Kong, Macau, Malaysia, Singapore, Western Australia, Brunei, Irkutsk, Central Indonesia, and most of Mongolia. History Philippine Standard Time was instituted through Batas Pambansa Blg. 8 (that defined the metric system), approved on December 2, 1978, and implemented on January 1, 1983. The Philippines is one of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1983 Luzon Earthquake
On August 17, 1983, at 20:17 PST ( UTC+08:00), an earthquake struck the island of Luzon in the Philippines. The shock had a surface wave magnitude of 6.5 and a maximum Mercalli intensity of VIII (''Severe''), killing 16 people and injuring 47. Seven towns were damaged, several buildings collapsed, and electricity was cut off in Laoag. Features like sand volcanoes and cracks formed during the quake. Damage and casualties The earthquake struck at 8:18 PM and had a surface wave magnitude of 6.5. It was the most powerful earthquake to strike the Philippines in seven years. Shaking lasted 20 seconds and damaged seven towns extensively, its greatest damage occurring near Pasuquin, Laoag, Sarrat, and Batac in the Ilocos Norte province. Early reports claimed that 17 were killed and 80 were injured, but these numbers were later revised to 16 and 47, respectively. A four-storey building collapsed, and the salesmen inside waited as long as 17 hours to be rescued; one man was rescued only ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Landslide
Landslides, also known as landslips, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, deep-seated grade (slope), slope failures, mudflows, and debris flows. Landslides occur in a variety of environments, characterized by either steep or gentle slope gradients, from mountain ranges to coastal cliffs or even underwater, in which case they are called submarine landslides. Gravity is the primary driving force for a landslide to occur, but there are other factors affecting slope stability that produce specific conditions that make a slope prone to failure. In many cases, the landslide is triggered by a specific event (such as a heavy rainfall, an earthquake, a slope cut to build a road, and many others), although this is not always identifiable. Causes Landslides occur when the slope (or a portion of it) undergoes some processes that change its condition from stable to unstable. This is essentially due to a decrease in the She ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Focal Mechanism
The focal mechanism of an earthquake describes the deformation in the source region that generates the seismic waves. In the case of a fault-related event it refers to the orientation of the fault plane that slipped and the slip vector and is also known as a fault-plane solution. Focal mechanisms are derived from a solution of the moment tensor for the earthquake, which itself is estimated by an analysis of observed seismic waveforms. The focal mechanism can be derived from observing the pattern of "first motions", that is, whether the first arriving P waves break up or down. This method was used before waveforms were recorded and analysed digitally and this method is still used for earthquakes too small for easy moment tensor solution. Focal mechanisms are now mainly derived using semi-automatic analysis of the recorded waveforms. Moment tensor solutions The moment tensor solution is typically displayed graphically using a so-called ''beachball'' diagram. The pattern of en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plate Tectonics
Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large tectonic plates which have been slowly moving since about 3.4 billion years ago. The model builds on the concept of ''continental drift'', an idea developed during the first decades of the 20th century. Plate tectonics came to be generally accepted by geoscientists after seafloor spreading was validated in the mid to late 1960s. Earth's lithosphere, which is the rigid outermost shell of the planet (the crust and upper mantle), is broken into seven or eight major plates (depending on how they are defined) and many minor plates or "platelets". Where the plates meet, their relative motion determines the type of plate boundary: '' convergent'', '' divergent'', or ''transform''. Earthquakes, volcanic activity, mountain-building, and oceanic tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manila Trench
The Manila Trench is an oceanic trench in the Pacific Ocean, located west of the islands of Luzon and Mindoro in the Philippines. The trench reaches a depth of about , in contrast with the average depth of the South China Sea of about . It is created by subduction, in which the Sunda Plate (part of Eurasian Plate) is subducting under the Philippine Mobile Belt, producing this almost N-S trending trench. The convergent boundary is terminated to the north by the Taiwan collision zone, and to the south by the Mindoro terrane (Sulu-Palawan block colliding with SW Luzon). It is an area pervaded by negative gravity anomalies. The Manila Trench is associated with frequent earthquakes, and the subduction zone is responsible for the belt of volcanoes on the west side of the Philippine island of Luzon, which includes Mount Pinatubo. Convergence between the Philippine Mobile Belt and the Sunda Plate have been estimated using GPS measurements, and this value ranges from ~ 50+ mm/yr in T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sunda Plate
The Sunda Plate is a minor tectonic plate straddling the Equator in the Eastern Hemisphere on which the majority of Southeast Asia is located. The Sunda Plate was formerly considered a part of the Eurasian Plate, but the GPS measurements have confirmed its independent movement at 10 mm/yr eastward relative to Eurasia. Extent The Sunda Plate includes the South China Sea, the Andaman Sea, southern parts of Vietnam and Thailand along with Malaysia and the islands of Borneo, Sumatra, Java, and part of Sulawesi in Indonesia, plus the south-western Philippines islands of Palawan and the Sulu Archipelago. The Sunda is bounded in the east by the Philippine Mobile Belt, Molucca Sea Collision Zone, Molucca Sea Plate, Banda Sea Plate and Timor Plate; to the south and west by the Australian Plate; and to the north by the Burma Plate, Eurasian Plate; and Yangtze Plate. The Indo-Australian Plate dips beneath the Sunda Plate along the Sunda Trench, which generates frequent earthq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philippine Sea Plate
The Philippine Sea Plate or the Philippine Plate is a tectonic plate comprising oceanic lithosphere that lies beneath the Philippine Sea, to the east of the Philippines. Most segments of the Philippines, including northern Luzon, are part of the Philippine Mobile Belt, which is geologically and tectonically separate from the Philippine Sea Plate. The plate is bordered mostly by convergent boundaries:Smoczyk, G.M., Hayes, G.P., Hamburger, M.W., Benz, H.M., Villaseñor, Antonio, and Furlong, K.P., 2013Seismicity of the Earth 1900–2012 Philippine Sea Plate and vicinity U.S. Geological Survey Open-File Report 2010–1083-M, scale 1:10,000,000, ''https://dx.doi.org/10.3133/ofr20101083m''. To the north, the Philippine Sea Plate meets the Okhotsk Plate at the Nankai Trough. The Philippine Sea Plate, the Amurian Plate, and the Okhotsk Plate meet near Mount Fuji in Japan. The thickened crust of the Izu–Bonin–Mariana arc colliding with Japan constitutes the Izu Collision Zone. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philippine Trench
The Philippine Trench (also Philippine Deep, Mindanao Trench, and Mindanao Deep) is a submarine trench to the east of the Philippines. The trench is located in the Philippine sea of the western North Pacific Ocean and continues NNW-SSE. It has a length of approximately and a width of about from the center of the Philippine island of Luzon trending southeast to the northern Maluku island of Halmahera in Indonesia. At its deepest point, the trench reaches 10,540 meters (34,580 ft or 5,760 fathoms). Immediately to the north of the Philippine Trench is the East Luzon Trench. They are separated, with their continuity interrupted and displaced, by Benham Plateau on the Philippine Sea Plate. Information The Philippine trench is hypothesized to be younger than 8–9 million years old. The central part of the Philippine fault formed during the Plio-Pleistocene times is considered to be an active depression of the Earth's crust. The trench formed from a coll ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subduction Zones
Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the heavier plate dives beneath the second plate and sinks into the mantle. A region where this process occurs is known as a subduction zone, and its surface expression is known as an arc-trench complex. The process of subduction has created most of the Earth's continental crust. Rates of subduction are typically measured in centimeters per year, with the average rate of convergence being approximately two to eight centimeters per year along most plate boundaries. Subduction is possible because the cold oceanic lithosphere is slightly denser than the underlying asthenosphere, the hot, ductile layer in the upper mantle underlying the cold, rigid lithosphere. Once initiated, stable subduction is driven mostly by the negative buoyancy of the dens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subduction Tectonics Of The Philippines
The subduction tectonics of the Philippines is the control of geology over the Philippine archipelago. The Philippine region is seismically active and has been progressively constructed by plates converging towards each other in multiple directions. The region is bounded by subduction zones, where surrounding oceanic plates to the east and west slide towards the centre of the Philippine archipelago. Subduction results in deep oceanic trenches, such as the Philippine Trench and Manila Trench, bounding the eastern and western sides of the Philippine archipelago, respectively. The Philippine archipelago is also cut along its length by a left-lateral strike-slip fault known as the Philippine Fault. The region is also known as the Philippine mobile belt due to its complex tectonic setting. Active subduction disturbs the crust, leading to volcanic activity, earthquakes and tsunamis, making the Philippines one of the most hazard-prone regions on Earth. Tectonic units Philippi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2019 Luzon Earthquake
On April 22, 2019, a 6.1 magnitude earthquake struck the island of Luzon in the Philippines, leaving at least 18 dead, three missing and injuring at least 256 others. Despite the fact that the epicenter was in Zambales, most of the damage to infrastructure occurred in the neighboring province of Pampanga, which suffered damage to 29 buildings and structures. Earthquake The Philippine Institute of Volcanology and Seismology (PHIVOLCS) initially reported an earthquake of magnitude 5.7 striking at 17:11 PST with an epicenter two kilometers N 28° E of Castillejos, Zambales. The report was later revised to an earthquake of magnitude 6.1 with epicenter 18 kilometers N 58° E of Castillejos. The fault from which the earthquake originated is yet to be determined, with geologists focusing on two nearby fault systems, the Iba Fault and the East Zambales Fault, trying to ascertain the source of the earthquake. Casualties As of April 29, 2019, the National Disaster Risk Reduction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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