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1699 Java Earthquake
On the morning of January 5, 1699, a violent earthquake rocked the then Dutch East Indies city of Batavia on the island of Java. In the contemporary period, the Indonesian capital city Jakarta. Dutch accounts of the event described the earthquake as being "so heavy and strong" and beyond comparable to other known earthquakes. This event was so large that it was felt throughout west Java, and southern Sumatra. Tectonic setting The Indonesian islands of Java, Sumatra and Lesser Sunda chain lie along a destructive plate boundary where the Australian Plate meets the Sunda Plate. The plates converge, with the Australian Plate being much denser as it is oceanic lithosphere, subducting beneath the less dense Sunda Plate. Subduction is responsible for the large megathrust earthquakes along the west coast of Sumatra and south coast of Java. It also plays a significant role in the volcanic activity on the islands. However, intraplate earthquakes can also occur as the Australian Plate d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intraplate Earthquake
The term intraplate earthquake refers to a variety of earthquake that occurs ''within the interior'' of a tectonic plate; this stands in contrast to an interplate earthquake, which occurs ''at the boundary'' of a tectonic plate. Intraplate earthquakes are often called "intraslab earthquakes", especially when occurring in microplates. Intraplate earthquakes are relatively rare compared to the more familiar boundary-located interplate earthquakes. Structures far from plate boundaries tend to lack seismic retrofitting, so large intraplate earthquakes can inflict heavy damage. Examples of damaging intraplate earthquakes are the devastating Gujarat earthquake in 2001, the 2012 Indian Ocean earthquakes, the 2017 Puebla earthquake, the 1811–1812 earthquakes in New Madrid, Missouri, and the 1886 earthquake in Charleston, South Carolina. Fault zones within tectonic plates The surface of the Earth is made up of seven primary and eight secondary tectonic plates, plus dozens of tert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megathrust Earthquakes
Megathrust earthquakes occur at convergent plate boundaries, where one tectonic plate is forced underneath another. The earthquakes are caused by slip along the thrust fault that forms the contact between the two plates. These interplate earthquakes are the planet's most powerful, with moment magnitudes (''Mw'') that can exceed 9.0. Since 1900, all earthquakes of magnitude 9.0 or greater have been megathrust earthquakes. The thrust faults responsible for megathrust earthquakes often lie at the bottom of oceanic trenches; in such cases, the earthquakes can abruptly displace the sea floor over a large area. As a result, megathrust earthquakes often generate tsunamis that are considerably more destructive than the earthquakes themselves. Teletsunamis can cross ocean basins to devastate areas far from the original earthquake. Terminology and mechanism The term ''megathrust'' refers to an extremely large thrust fault, typically formed at the plate interface along a subduction zo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mercalli Intensity
The Modified Mercalli intensity scale (MM, MMI, or MCS), developed from Giuseppe Mercalli's Mercalli intensity scale of 1902, is a seismic intensity scale used for measuring the intensity of shaking produced by an earthquake. It measures the effects of an earthquake at a given location, distinguished from the earthquake's inherent force or strength as measured by seismic magnitude scales (such as the "" magnitude usually reported for an earthquake). While shaking is caused by the seismic energy released by an earthquake, earthquakes differ in how much of their energy is radiated as seismic waves. Deeper earthquakes also have less interaction with the surface, and their energy is spread out across a larger volume. Shaking intensity is localized, generally diminishing with distance from the earthquake's epicenter, but can be amplified in sedimentary basins and certain kinds of unconsolidated soils. Intensity scales empirically categorize the intensity of shaking based on the effect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epicenter
The epicenter, epicentre () or epicentrum in seismology is the point on the Earth's surface directly above a hypocenter or focus, the point where an earthquake or an underground explosion originates. Surface damage Before the instrumental period of earthquake observation, the epicenter was thought to be the location where the greatest damage occurred, but the subsurface fault rupture may be long and spread surface damage across the entire rupture zone. As an example, in the magnitude 7.9 Denali earthquake of 2002 in Alaska, the epicenter was at the western end of the rupture, but the greatest damage was about away at the eastern end. Focal depths of earthquakes occurring in continental crust mostly range from . Continental earthquakes below are rare whereas in subduction zone earthquakes can originate at depths deeper than . Epicentral distance During an earthquake, seismic waves propagate in all directions from the hypocenter. Seismic shadowing occurs on the opposite s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moment Magnitude
The moment magnitude scale (MMS; denoted explicitly with or Mw, and generally implied with use of a single M for magnitude) is a measure of an earthquake's magnitude ("size" or strength) based on its seismic moment. It was defined in a 1979 paper by Thomas C. Hanks and Hiroo Kanamori. Similar to the local magnitude/Richter scale () defined by Charles Francis Richter in 1935, it uses a logarithmic scale; small earthquakes have approximately the same magnitudes on both scales. Despite the difference, news media often says "Richter scale" when referring to the moment magnitude scale. Moment magnitude () is considered the authoritative magnitude scale for ranking earthquakes by size. It is more directly related to the energy of an earthquake than other scales, and does not saturate—that is, it does not underestimate magnitudes as other scales do in certain conditions. It has become the standard scale used by seismological authorities like the U.S. Geological SurveyThe "USGS Eart ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subducts
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] |
Sunda Megathrust
The Sunda megathrust is a fault that extends approximately 5,500 km (3300 mi) from Myanmar (Burma) in the north, running along the southwestern side of Sumatra, to the south of Java and Bali before terminating near Australia. It is a megathrust, located at a convergent plate boundary where it forms the interface between the overriding Eurasian plate and the subducting Indo-Australian plate. It is one of the most seismogenic structures on Earth, being responsible for many great and giant earthquakes, including the 2004 Indian Ocean earthquake and tsunami that killed over 227,000 people. The Sunda megathrust can be divided into the ''Andaman Megathrust'', ''Sumatra(n) Megathrust'' and ''Java(n) Megathrust''. The Bali-Sumbawa segment is much less active and therefore does not have the "megathrust" term associated with it. Tectonic setting The subducting plate consists of two protoplates, the Indian and Australian plates. Similarly, the overriding plate consists of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Banten (town)
Banten, also written as Bantam, is a port town near the western end of Java, Indonesia. It has a secure harbour at the mouth of Banten River, a navigable passage for light craft into the island's interior. The town is close to the Sunda Strait through which important ocean-going traffic passes between Java and Sumatra. Formerly Old Banten was the capital of a sultanate in the area, was strategically important and a major centre for trade. History In the 5th century Banten was part of the Tarumanagara kingdom. The Lebak relic inscriptions, found in lowland villages on the edge of Ci Danghiyang, Munjul, Pandeglang, Banten, were discovered in 1947 and contains 2 lines of poetry with Pallawa script and Sanskrit language. The inscriptions mentioned the courage of king Purnawarman. After the collapse of the kingdom Tarumanagara following an attack by the Srivijaya empire, power in western Java fell to the Kingdom of Sunda. The Chinese source, ''Chu-fan-chi'', written c. 120 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Java Sea
The Java Sea ( id, Laut Jawa, jv, Segara Jawa) is an extensive shallow sea on the Sunda Shelf, between the Indonesian islands of Borneo to the north, Java to the south, Sumatra to the west, and Sulawesi to the east. Karimata Strait to its northwest links it to the South China Sea. It is a part of the western Pacific Ocean. Geography The Java Sea covers the southern section of the Sunda Shelf. A shallow sea, it has a mean depth of . It measures about east-west by north-southGoogleEarth and occupies a total surface area of . It formed as sea levels rose at the end of the last ice age. Its almost uniformly flat bottom, and the presence of drainage channels (traceable to the mouths of island rivers), indicate that the Sunda Shelf was once a stable, dry, low-relief land area ( peneplain) above which were left standing a few monadnocks (granite hills that, due to their resistance to erosion, form the present islands). Extent The International Hydrographic Organization (IHO) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ci Liwung
Ci Liwung (often written as Ciliwung; also as Tjiliwoeng in Dutch, Sundanese: ᮎᮤᮜᮤᮝᮥᮀ) is a 119 km long river in the northwestern region of Java where it flows through two provinces, West Java and the special region of Jakarta. The natural estuary of the Ciliwung river, known as the Kali Besar ("Big River"), was an important strategic point for trade in the precolonial and colonial periods and was instrumental in the founding of the port city of Jakarta, but has been lost from reorganization of the watercourse of the rivers around the area into canals. Etymology The etymology of ''Ciliwung'' is uncertain; the two least implausible assumptions are "the whirlpool" (compare Sundanese ''liwung'' "be distressed, upset") or "the meandering one" (compare Malay ''liuk'', ''liut'' "to twist"). It is possible that the name originated from one of the many epithets of the king of Pajajaran Sri Baduga Maharaja, among them is Prabu Haliwung, so named because of his temper ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Debris Flow
Debris flows are geological phenomena in which water-laden masses of soil and fragmented rock rush down mountainsides, funnel into stream channels, entrain objects in their paths, and form thick, muddy deposits on valley floors. They generally have bulk densities comparable to those of rock avalanches and other types of landslides (roughly 2000 kilograms per cubic meter), but owing to widespread sediment liquefaction caused by high pore-fluid pressures, they can flow almost as fluidly as water. Debris flows descending steep channels commonly attain speeds that surpass 10 m/s (36 km/h), although some large flows can reach speeds that are much greater. Debris flows with volumes ranging up to about 100,000 cubic meters occur frequently in mountainous regions worldwide. The largest prehistoric flows have had volumes exceeding 1 billion cubic meters (i.e., 1 cubic kilometer). As a result of their high sediment concentrations and mobility, debris flows can be very de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Landslides
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 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 shear strength o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
