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2018 Hawaii Earthquake
On May 4, 2018, an earthquake with a magnitude of 6.9 struck Hawaii island in the Hawaii archipelago at around 12:33 p.m. local time. The earthquake's epicenter was near the south flank of Kīlauea, which has been the site of seismic and volcanic activity since late April of that year. According to the United States Geological Survey the quake was related to the new lava outbreaks at the volcano, and it resulted in the Hilina Slump moving about two feet. It was the largest earthquake to affect Hawaii since the 1975 earthquake, which affected the same region, killing two people and injuring another 28. The earthquake had a maximum strength on the Mercalli intensity scale of VIII (''Severe''). The earthquake was preceded by a smaller event, measuring 5.4, that was felt across the island and as far away as Oahu. The earthquake produced a minor tsunami that reached a maximum height of 40 cm (15.7 in.) in Kapoho, 20 cm (7.9 in.) in Hilo and 15 cm (5.9 in.) in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2018 Hawaii Earthquake
On May 4, 2018, an earthquake with a magnitude of 6.9 struck Hawaii island in the Hawaii archipelago at around 12:33 p.m. local time. The earthquake's epicenter was near the south flank of Kīlauea, which has been the site of seismic and volcanic activity since late April of that year. According to the United States Geological Survey the quake was related to the new lava outbreaks at the volcano, and it resulted in the Hilina Slump moving about two feet. It was the largest earthquake to affect Hawaii since the 1975 earthquake, which affected the same region, killing two people and injuring another 28. The earthquake had a maximum strength on the Mercalli intensity scale of VIII (''Severe''). The earthquake was preceded by a smaller event, measuring 5.4, that was felt across the island and as far away as Oahu. The earthquake produced a minor tsunami that reached a maximum height of 40 cm (15.7 in.) in Kapoho, 20 cm (7.9 in.) in Hilo and 15 cm (5.9 in.) in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oahu
Oahu () ( Hawaiian: ''Oʻahu'' ()), also known as "The Gathering Place", is the third-largest of the Hawaiian Islands. It is home to roughly one million people—over two-thirds of the population of the U.S. state of Hawaii. The island of O’ahu and the Northwestern Hawaiian Islands constitute the City and County of Honolulu. The state capital, Honolulu, is on Oʻahu's southeast coast. Oʻahu had a population of 1,016,508 according to the 2020 U.S. Census, up from 953,207 people in 2010 (approximately 70% of the total 1,455,271 population of the State of Hawaii, with approximately 81% of those living in or near the Honolulu urban area). Name The Island of O{{okinaahu in Hawaii is often nicknamed (or translated as) ''"The Gathering Place"''. It appears that O{{okinaahu grew into this nickname; it is currently the most populated Hawaiian Island, however, in ancient times, O{{okinaahu was not populous and was outranked by the status of other islands. The translation of ''"gat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Love Wave
In elastodynamics, Love waves, named after Augustus Edward Hough Love, are horizontally polarized surface waves. The Love wave is a result of the interference of many shear waves ( S-waves) guided by an elastic layer, which is ''welded'' to an elastic half space on one side while bordering a vacuum on the other side. In seismology, Love waves (also known as Q waves (''Q''uer: German for lateral)) are surface seismic waves that cause horizontal shifting of the Earth during an earthquake. Augustus Edward Hough Love predicted the existence of Love waves mathematically in 1911. They form a distinct class, different from other types of seismic waves, such as P-waves and S-waves (both body waves), or Rayleigh waves (another type of surface wave). Love waves travel with a lower velocity than P- or S- waves, but faster than Rayleigh waves. These waves are observed only when there is a low velocity layer overlying a high velocity layer/ sub–layers. Description The particle moti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrust Fault
A thrust fault is a break in the Earth's crust, across which older rocks are pushed above younger rocks. Thrust geometry and nomenclature Reverse faults A thrust fault is a type of reverse fault that has a dip of 45 degrees or less. If the angle of the fault plane is lower (often less than 15 degrees from the horizontal) and the displacement of the overlying block is large (often in the kilometer range) the fault is called an ''overthrust'' or ''overthrust fault''. Erosion can remove part of the overlying block, creating a ''fenster'' (or ''window'') – when the underlying block is exposed only in a relatively small area. When erosion removes most of the overlying block, leaving island-like remnants resting on the lower block, the remnants are called ''klippen'' (singular ''klippe''). Blind thrust faults If the fault plane terminates before it reaches the Earth's surface, it is referred to as a ''blind thrust'' fault. Because of the lack of surface evidence, blind thr ... [...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 o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foreshock
A foreshock is an earthquake that occurs before a larger seismic event (the mainshock) and is related to it in both time and space. The designation of an earthquake as ''foreshock'', ''mainshock'' or aftershock is only possible after the full sequence of events has happened. Occurrence Foreshock activity has been detected for about 40% of all moderate to large earthquakes, and about 70% for events of M>7.0. They occur from a matter of minutes to days or even longer before the main shock; for example, the 2002 Sumatra earthquake is regarded as a foreshock of the 2004 Indian Ocean earthquake with a delay of more than two years between the two events. Some great earthquakes (M>8.0) show no foreshock activity at all, such as the M8.6 1950 India–China earthquake. The increase in foreshock activity is difficult to quantify for individual earthquakes but becomes apparent when combining the results of many different events. From such combined observations, the increase before the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1868 Hawaii Earthquake
The 1868 Hawaii earthquake was the largest recorded in the history of Hawaii island, with an estimated magnitude of 7.9 and a maximum Mercalli intensity of X (''Extreme''). The earthquake occurred at 4 p.m. local time on April 2, 1868 and caused a landslide and tsunami that led to 77 deaths. The aftershock sequence for this event has continued up to the present day. Background The island of Hawaii (commonly called the "Big Island") is the currently active volcanic center of the Hawaiian Islands formed over the Hawaii hotspot. Two of the active volcanoes on the Big Island are Kīlauea and Mauna Loa with a newer submarine volcano forming the Kamaʻehuakanaloa Seamount (formerly Loihi) to the southeast of the island. Continued growth of the southeastern part of the island is accompanied by major slumping and southeastward movement of the flanks of the two volcanoes. This flank displacement is linked to extension within the rift zones associated with both of the active volcanoes, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hilina Slump
The Hilina Slump, on the south flank of the Kīlauea Volcano on the southeast coast of the Big Island of Hawaiʻi, is the most notable of several landslides that ring each of the Hawaiian Islands. These landslides are the means by which material deposited at a volcano's vents are transferred downward and seaward, eventually spilling onto the seabed to broaden the island. Kīlauea's entire south flank, extending out to Cape Kumukahi, is currently sliding seaward, with some parts of the central portion (over looking the Hilina slump) moving as much as per year, pushed by the forceful injection of magma and pulled by gravity. Current movement of the Hilina slump and recent volcanic activity, coupled with evidence of massive submarine slides in the geological past, has led to claims that megatsunamis might result if the south flank of Kīlauea should suddenly fail. Geology The Hawaiian Islands are volcanoes, the newest part of the Hawaiian-Emperor seamount chain, created ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oceanic Crust
Oceanic crust is the uppermost layer of the oceanic portion of the tectonic plates. It is composed of the upper oceanic crust, with pillow lavas and a dike complex, and the lower oceanic crust, composed of troctolite, gabbro and ultramafic cumulates. The crust overlies the rigid uppermost layer of the mantle. The crust and the rigid upper mantle layer together constitute oceanic lithosphere. Oceanic crust is primarily composed of mafic rocks, or sima, which is rich in iron and magnesium. It is thinner than continental crust, or sial, generally less than 10 kilometers thick; however, it is denser, having a mean density of about 3.0 grams per cubic centimeter as opposed to continental crust which has a density of about 2.7 grams per cubic centimeter. The crust uppermost is the result of the cooling of magma derived from mantle material below the plate. The magma is injected into the spreading center, which consists mainly of a partly solidified crystal mush derived from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Décollement
Décollement () is a gliding plane between two rock masses, also known as a basal detachment fault. Décollements are a deformational structure, resulting in independent styles of deformation in the rocks above and below the fault. They are associated with both compressional settings (involving folding and overthrusting) and extensional settings. Origin The term was first used by geologists studying the structure of the Swiss Jura Mountains, coined in 1907 by A. Buxtorf, who released a paper that theorized that the Jura is the frontal part of a décollement at the base of a nappe, rooted in the faraway Swiss Alps. Marcel Alexandre Bertrand published a paper in 1884 that dealt with Alpine nappism. Thin-skinned tectonics was implied in that paper but the actual term was not used until Buxtorf's 1907 publication. Formation Décollements are caused by surface forces, which 'push' at converging plate boundaries, facilitated by body forces (gravity sliding). Mechanically ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PTWC
The Pacific Tsunami Warning Center (PTWC) is one of two tsunami warning centers that are operated by NOAA in the United States. Headquartered on Ford Island, HI, the PTWC is part of an international tsunami warning system (TWS) program and serves as the operational center for TWS of the Pacific issuing bulletins and warnings to participating members and other nations in the Pacific Ocean area of responsibility. It is also the regional (local) warning center for the State of Hawaii. The other tsunami warning center is the National Tsunami Warning Center (NTWC) in Palmer, Alaska, serving all coastal regions of Canada and the United States except Hawaii, the Caribbean Sea and the Gulf of Mexico. The PTWC was established in 1949, following the 1946 Aleutian Island earthquake and a tsunami that resulted in 165 casualties in Hawaii and Alaska. The PTWC uses seismic data as its starting point, but then takes into account oceanographic data when calculating possible threats. Tide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Honuapo
Honuapo or Honuʻapo is a ghost town on the island of Hawaii in the U.S. state of Hawaii. It was a thriving port town from the 1870s to the 1930s. The port was used to transport ''Colocasia esculenta'' (taro), and sugarcane Sugarcane or sugar cane is a species of (often hybrid) tall, perennial grass (in the genus '' Saccharum'', tribe Andropogoneae) that is used for sugar production. The plants are 2–6 m (6–20 ft) tall with stout, jointed, fibrous stalk .... Little of the town remains today other than the pier, which was destroyed in 1946 by a tsunami. References Ghost towns in Hawaii {{Hawaii-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
