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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. In most earthquakes, the epicenter is the point where the greatest damage takes place, but the length of the subsurface fault rupture may indeed be a long one, damage can be spread on the surface across the entire rupture zone; as an example, in the magnitude 7.9 2002 Denali earthquake in Alaska, the epicenter was at the western end of the rupture, but the greatest damage was about 330 km away at the eastern end. Focal depths of earthquakes occurring in continental crust range from two to twenty kilometres. Continental earthquakes below 20 km are rare whereas in subduction zones earthquakes can originate at depths deeper than 600 km. During an earthquake, seismic waves propagate in all directions from the hypocenter. Seismic shadowing occurs on the opposite side of the Earth from the earthquake epicenter because the planet's liquid outer core refracts the longitudinal or compressional while it absorbs the transverse or shear waves.

Outside the seismic shadow zone, both types of wave can be detected but, because of their different velocities and paths through the Earth, they arrive at different times. By measuring the time difference on any seismograph and the distance on a travel-time graph on which the P-wave and S-wave have the same separation, geologists can calculate the distance to the quake's epicenter; this distance is called the epicentral distance measured in ° and denoted as Δ in seismology. Once distances from the epicenter have been calculated from at least three seismographic measuring stations, the point can be located, using trilateration. Epicentral distance is used in calculating seismic magnitudes as developed by Richter and Gutenberg; the point at which fault slipping begins is referred to as the focus of the earthquake. The fault rupture begins at the focus and expands along the fault surface; the rupture stops where the stresses become insufficient to continue breaking the fault or where the rupture enters ductile material.

The magnitude of an earthquake is related to the total area of its fault rupture. Most earthquakes are small, with rupture dimensions less than the depth of the focus so the rupture doesn't break the surface, but in high magnitude, destructive earthquakes, surface breaks are common. Fault ruptures in large earthquakes can extend for more than 100 km; when a fault ruptures unilaterally the waves are stronger in one direction along the fault. The word is derived from the New Latin noun epicentrum, the latinisation of the ancient Greek adjective ἐπίκεντρος, "occupying a cardinal point, situated on a centre", from ἐπί "on, upon, at" and κέντρον "centre"; the term was coined by the Irish seismologist Robert Mallet. It is used to mean focal point, as in "Travel is restricted in the Chinese province thought to be the epicentre of the SARS outbreak." Garner's Modern American Usage gives several examples of use in which "epicenter" is used to mean "center". Garner refers to a William Safire article in which Safire quotes a geophysicist as attributing the use of the term to "spurious erudition on the part of writers combined with scientific illiteracy on the part of copy editors".

Garner has noted that these usages may describe "focal points of unstable and destructive environments."

Lea Bridge railway station

Lea Bridge is a railway station on the line between Stratford and Tottenham Hale on the Lea Valley Lines, which reopened on the evening of 15 May 2016 with the full service beginning on 16 May 2016, operated by Greater Anglia. The station is located on Argall Way, close to its junction with Lea Bridge Road and Orient Way, serving the areas of Lea Bridge and Leyton in the London Borough of Waltham Forest, north-east London; the original station operated from 1840 to 1985 and was accessed via the north side of Lea Bridge Road as it crosses the tracks. The station was opened on 15 September 1840 by the Northern and Eastern Railway as Lea Bridge Road and is thought to be the earliest example of a station having its building on a road bridge, with staircases down to the platforms; the original station building was an attractive Italianate style structure designed by Sancton Wood and featured a bell turret on the roof with a bell, rung when a train was due. The line was laid to a gauge of 5 ft but this had been identified as non-standard, between 5 September and 7 October 1844 the whole network was re-laid to 4 ft 8 1⁄2 in standard gauge.

The Northern and Eastern Railway was leased by the Eastern Counties Railway, which operated the station. The ECR became part of the Great Eastern Railway in 1862; the GER established its signal works on the eastern side of the line. To the south of the station were the large Temple Mills marshalling yards, the station would have seen large numbers of goods trains passing. In 1870 a line was opened to Shern Hall Street station and a shuttle service operated between Lea Bridge and Shern Hall Street, commencing traffic on 24 April 1870. Prior to this, a horse bus operating between Walthamstow and Lea Bridge had met all trains arriving at the station; the station was renamed Lea Bridge in 1841. In 1923 the GER became part of the North Eastern Railway. In the 1930s the station was served by trains to Liverpool Street, to North Woolwich, to Hertford East and Palace Gates. At that time there were Sunday services via the Hall Farm curve to the Chingford branch. On 31 March 1944 the station building was gutted by fire.

After World War II, in 1948, the railways of the UK were nationalised, operation of the station passed to British Railways Eastern Region. The Hall Farm spur line through to the Chingford branch was used and, despite being electrified in 1960, the line was lifted in 1967; the station became an unstaffed halt in 1976 and the station building was demolished at about that time. By the only trains serving Lea Bridge were those operating between Tottenham Hale and North Woolwich via Stratford, the withdrawal of that service led to the closure of the station on 8 July 1985; the simple open-sided shelter, located on the road bridge over the tracks, which had replaced the original station buildings, was demolished in 1985. The last train consisted of a two-car Cravens Class 105 DMU. In December 2005 a new service to and from Stratford reintroduced regular passenger trains passing through the closed station. For many years, plans were under consideration to rebuild and reopen the station and the nearby Hall Farm Curve junction, as part of wider plans for the redevelopment of the Stratford and Lower Lea Valley area.

In January 2013 it was announced that plans had been approved to reopen the station. Construction on the £6.5m scheme was planned to start in spring 2014. The station was included in Network Rail's Route Specification for Anglia in 2014 for opening within the next five years. In October 2013, the overgrown platforms were cleared in preparation for construction of the new station building; the new buildings were to be situated on the up side rather than on the road bridge over the line, the platforms were to be linked by a footbridge. Estimates by Transport for London show 352,000 entries and exits annually by 2031 with a service of two trains per hour, it was hoped that—after 29 years of closure—the station would reopen in late 2014. The construction date slipped, but work started in July 2015. All services at Lea Bridge are run by Greater Anglia; the off peak service is: 4 tph to Stratford 2 tph to Bishop's Stortford 2 tph to Meridian WaterDuring the peak periods, additional services run to/from Hertford East.

There are a few early morning and late evening services that run to/from London Liverpool Street. On Sundays, the Bishops Stortford service runs to Hertford East instead. London Buses routes that serve the station are 48, 55 and 56 and night routes N38 and N55. Map sources London's Abandoned Stations - Lea Bridge

Sulphur Springs, Benton County, Arkansas

Sulphur Springs is a city in Benton County, United States. The population was 511 at the 2010 census, it is AR-MO Metropolitan Statistical Area. Sulphur Springs got its start in 1885 as a mineral spa resort. Sulphur Springs is located in northwest Benton County at 36°29′01″N 94°27′33″W; the city center is about one mile south of the Missouri-Arkansas state line. Arkansas Highway 59 runs through the city, leading north to Noel and south to Gravette. According to the United States Census Bureau, the city has a total area of 1.0 square mile, all land. At the 2000 census, there were 229 households and 160 families residing in the city; the population density was 667.1 per square mile. There were 279 housing units at an average density of 277.4 per square mile. The racial makeup of the city was 86.74% White, 2.24% Black or African American, 0.89% Native American, 0.30% Asian, 7.15% from other races, 2.68% from two or more races. Hispanic or Latino of any race were 16.69% of the population. There were 229 households of which 40.2% had children under the age of 18 living with them, 52.4% were married couples living together, 11.4% had a female householder with no husband present, 29.7% were non-families.

24.0% of all households were made up of individuals and 12.2% had someone living alone, 65 years of age or older. The average household size was 2.93 and the average family size was 3.45. 32.8% of the population were under the age of 18, 9.2% from 18 to 24, 27.6% from 25 to 44, 18.9% from 45 to 64, 11.5% who were 65 years of age or older. The median age was 30 years. For every 100 females, there were 95.1 males. For every 100 females age 18 and over, there were 90.3 males. The median household income was $25,536 and the median family income was $29,844. Males had a median income of $21,354 and females $19,000; the per capita income was $9,542. About 20.0% of families and 25.8% of the population were below the poverty line, including 30.2% of those under age 18 and 10.0% of those age 65 or over. The Harbor House in Sulphur Springs has stood for over one hundred years, it still serves as a religious guest house for tourists. Jim Hendren, a businessman from Sulphur Springs, represents District 2 in the Arkansas Senate.

He is a former member of the Arkansas House of Representatives. Kim Hendren, father of the above served in both houses of the Arkansas General Assembly Sulphur Springs was the boyhood home of noted American watercolorist W Emerton Heitland. Sulphur Springs blog