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1977 Tonga Earthquake
The 1977 Tonga earthquake took place on 22 June at 12:08:33 UTC some 200 km southwest of Tongatapu, which shocks infecting all islands of the kingdom of Tonga. The earthquake measured 8.0 on the moment magnitude scale and had a maximum intensity of VIII (''Severe'') on the Mercalli intensity scale. The earthquake caused considerable damage to the infrastructures and some fatalities in most Tongan islands, with the most damage in Tongatapu and ʻEua and the least damage in Ha'apai and Vava'u. See also *List of earthquakes in 1977 *List of earthquakes in Tonga *Louisville Ridge The Louisville Ridge, also known as the Louisville Seamount Chain, is an underwater chain of over 70 seamounts located in the Southwest portion of the Pacific Ocean. As one of the longest seamount chains on Earth it stretches some Vanderkluysen, ... References Further reading * External links * Earthquakes in Tonga 1977 earthquakes 1977 in Tonga 1977 disasters in Oceania {{ea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fault (geology)
In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, such as the megathrust faults of subduction zones or transform faults. Energy release associated with rapid movement on active faults is the cause of most earthquakes. Faults may also displace slowly, by aseismic creep. A ''fault plane'' is the plane that represents the fracture surface of a fault. A ''fault trace'' or ''fault line'' is a place where the fault can be seen or mapped on the surface. A fault trace is also the line commonly plotted on geologic maps to represent a fault. A ''fault zone'' is a cluster of parallel faults. However, the term is also used for the zone of crushed rock along a single fault. Prolonged motion along closely spaced faults can blur the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tongatapu
Tongatapu is the main island of Tonga and the site of its capital, Nukualofa. It is located in Tonga's southern island group, to which it gives its name, and is the country's most populous island, with 74,611 residents (2016), 70.5% of the national population, on . Based on Google Earth Pro, its maximum elevation is at least above sea level along Liku Road at 21 degrees 15 minutes and 55.7 seconds south 175 degrees 08 minutes 06.4 seconds west, but could be even higher somewhere else. Tongatapu is Tonga's centre of government and the seat of its monarchy. Tongatapu has experienced more rapid economic development than the other islands of Tonga, and has thus attracted many internal migrants from them. Geography The island is (or including neighbouring islands) and rather flat, as it is built of coral limestone. The island is covered with thick fertile soil consisting of volcanic ash from neighbouring volcanoes. At the steep coast of the south, heights reach an average of , a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tonga
Tonga (, ; ), officially the Kingdom of Tonga ( to, Puleʻanga Fakatuʻi ʻo Tonga), is a Polynesian country and archipelago. The country has 171 islands – of which 45 are inhabited. Its total surface area is about , scattered over in the southern Pacific Ocean. As of 2021, according to Johnson's Tribune, Tonga has a population of 104,494, 70% of whom reside on the main island, Tongatapu. The country stretches approximately north-south. It is surrounded by Fiji and Wallis and Futuna (France) to the northwest; Samoa to the northeast; New Caledonia (France) and Vanuatu to the west; Niue (the nearest foreign territory) to the east; and Kermadec (New Zealand) to the southwest. Tonga is about from New Zealand's North Island. First inhabited roughly 2,500 years ago by the Lapita civilization, Tonga's Polynesian settlers gradually evolved a distinct and strong ethnic identity, language, and culture as the Tongan people. They were quick to establish a powerful footing acr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moment Magnitude Scale
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 scale, 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mercalli Intensity Scale
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] |
ʻEua
Eua is an island in the kingdom of Tonga. It is close to Tongatapu, but forms a separate administrative division. It has an area of , and a population in 2021 of 4,903 people. Geography Eua is a hilly island, the highest peaks are the ''Teemoa'' (chicken manure) 312 m, and the ''Vaiangina'' (watersprings) 305 m. The island is not volcanic, but was shaped by the rubbing of the Tonga Plate against the Pacific Plate, pushing Eua up and leaving the Tonga Trench on the bottom of the ocean, a short distance towards the east. The soil of Eua is volcanic, as is that of Tongatapu, but only the top layer, deposited by eruptions of nearby volcanoes ten thousands years ago. Under it are the solid rocks of pushed-up coral. Eua counts many huge caves and holes, not all of which have yet been explored. Eua and Niuatoputapu are the only islands in Tonga that have streams, and Ê¿Eua had the only bridge in the kingdom until Vavau also built one. The stream drains into the harbour n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Earthquakes In 1977
This is a list of earthquakes in 1977. Only earthquakes of magnitude 6 or above are included, unless they result in damage and/or casualties, or are notable for some other reason. Events in remote areas will not be listed but included in statistics and maps. Countries are entered on the lists in order of their status in this particular year. All dates are listed according to UTC time. Maximum intensities are indicated on the Mercalli intensity scale and are sourced from United States Geological Survey (USGS) ShakeMap data. Not a particularly busy year as far as the number of magnitude 7.0+ events with 11 being recorded. The largest event struck Indonesia in August and measured magnitude 8.3. The Solomon Islands were affected by a series of magnitude 7.5 events in April. Several events caused significant numbers of fatalities especially in Iran which had 3 earthquakes throughout the year with a combined death toll of around 1,120 people. The deadliest earthquake occurred in Romani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Earthquakes In Tonga
This is a list of earthquakes in Tonga: Earthquakes References Sources * {{DEFAULTSORT:Earthquakes In Tonga Tonga Tonga (, ; ), officially the Kingdom of Tonga ( to, Puleʻanga Fakatuʻi ʻo Tonga), is a Polynesian country and archipelago. The country has 171 islands – of which 45 are inhabited. Its total surface area is about , scattered over in ... Earthquakes in Tonga Earthquakes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Louisville Ridge
The Louisville Ridge, also known as the Louisville Seamount Chain, is an underwater chain of over 70 seamounts located in the Southwest portion of the Pacific Ocean. As one of the longest seamount chains on Earth it stretches some Vanderkluysen, L.; Mahoney, J. J.; Koppers, A. A.; and Lonsdale, P. F. (2007)Geochemical Evolution of the Louisville Seamount Chain American Geophysical Union, Fall Meeting 2007, abstract #V42B-06. from the Pacific-Antarctic Ridge northwest to the Tonga-Kermadec Trench, where it subducts under the Indo-Australian Plate as part of the Pacific Plate. The chain may have been formed by movement of the Pacific Plate over the Louisville hotspot or by leakage of magma from the shallow mantle up through the Eltanin fracture zone, which it follows closely. Depth-sounding data first revealed the existence of the seamount chain in 1972. Seamounts The Louisville Ridge includes the following: * Burton Seamount *Currituck Seamount * Danseur Seamount * Darvin Guyo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Seismological Centre
The International Seismological Centre (ISC) is a non-governmental, nonprofit organisation charged with the final collection, definitive analysis and publication of global seismicity. The ISC was formed in 1964 as an international organisation independent of national governments that would carry on the work of the International Seismological Summary in collecting and analyzing seismic data from around the world, and particularly to handle increased flow of data from the World-Wide Standard Seismograph Network (WWSSN), also established that year. The ISC considers its prime task to be the collection and re-analysis of all available earthquake seismic date in order to produce definitive data on earthquakes. The ISC's catalog is considered "the most complete and authoritative final depository of global earthquake parameter data." Purpose The main scientific goal of the Centre is the definitive compilation of earthquake information and the readings on which they are based. Collecti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
