The expression Richter Magnitude Scale refers to a number of ways to assign a single number to quantify the energy contained in an earthquake.

In all cases, the magnitude is a base-10 logarithmic scale obtained by calculating the logarithm of the amplitude of waves measured by a seismograph. An earthquake that measures 5.0 on the Richter scale has a shaking amplitude 10 times larger and corresponds to an energy release of √1000 ≈ 31.6 times greater than one that measures 4.0.^[1]

Since the 1970s the use of the Richter Magnitude Scale has largely been supplanted by the moment magnitude scale in many countries. However, the Richter Magnitude Scale is still widely used in Russia and other CIS countries.

Development[link]

Charles Richter, c. 1970

Developed in 1935 by Charles Richter in partnership with Beno Gutenberg, both from the California Institute of Technology, the scale was firstly intended to be used only in a particular study area in California, and on seismograms recorded on a particular instrument, the Wood-Anderson torsion seismograph. Richter originally reported values to the nearest quarter of a unit, but values were later reported with one decimal place. His motivation for creating the local magnitude scale was to compare the size of different earthquakes.^[1] His inspiration was the apparent magnitude scale used in astronomy to describe the brightness of stars and other celestial objects.^[2] Richter arbitrarily chose a magnitude 0 event to be an earthquake that would show a maximum combined horizontal displacement of 1 µm (0.00004 in) on a seismogram recorded using a Wood-Anderson torsion seismograph 100 km (62 mi) from the earthquake epicenter. This choice was intended to prevent negative magnitudes from being assigned. The smallest earthquakes that could be recorded and located at the time were of magnitude 3, approximately. However, the Richter scale has no lower limit, and sensitive modern seismographs now routinely record quakes with negative magnitudes.

M_L (local magnitude) was not designed to be applied to data with distances to the hypocenter of the earthquake greater than 600 km^[3] (373 mi). For national and local seismological observatories the standard magnitude scale is today still M_L. Unfortunately this scale saturates at M6.5, approximately, because the high frequency waves recorded locally have wavelengths shorter than the rupture lengths of large earthquakes.

To be able to measure the size of earthquakes around the globe, Gutenberg and Richter later developed a magnitude scale based on surface waves, surface wave magnitude M_S; and another based on body waves, body wave magnitude m_b.^[4] These are types of waves that are recorded at teleseismic distances. The two scales were adjusted such that they were consistent with the M_L scale. This succeeded better with the M_s scale than with the m_b scale. Both of these scales saturate when the earthquake is bigger than magnitude 8 and therefore the moment magnitude scale, M_w, was invented.^[5]

These older magnitude scales have been superseded by the implementation of methods for estimating the seismic moment, creating the moment magnitude scale, although the former are still widely used because they can be calculated quickly.

Details[link]

The Richter scale proper was defined in 1935 for particular circumstances and instruments; the instrument used saturated for strong earthquakes. The scale was replaced by the moment magnitude scale (MMS); for earthquakes adequately measured by the Richter scale, numerical values are approximately the same. Although values measured for earthquakes now are actually Failed to parse (Missing texvc executable; please see math/README to configure.): M_w

(MMS), they are frequently reported as Richter values, even for earthquakes of magnitude over 8, where the Richter scale becomes meaningless.

Anything above 5 is classified as a risk.^{[by whom?]}

The Richter and MMS scales measure the energy released by an earthquake; another scale, the Mercalli intensity scale, classifies earthquakes by their effects, from detectable by instruments but not noticeable to catastrophic. The energy and effects are not necessarily strongly correlated; a shallow earthquake in a populated area with soil of certain types can be far more intense than a much more energetic deep earthquake in an isolated area.

There are several scales which have historically been described as the "Richter scale," especially the local magnitude Failed to parse (Missing texvc executable; please see math/README to configure.): M_L and the surface wave Failed to parse (Missing texvc executable; please see math/README to configure.): M_s scale. In addition, the body wave magnitude, Failed to parse (Missing texvc executable; please see math/README to configure.): m_b , and the moment magnitude, Failed to parse (Missing texvc executable; please see math/README to configure.): M_w , abbreviated MMS, have been widely used for decades, and a couple of new techniques to measure magnitude are in the development stage.

All magnitude scales have been designed to give numerically similar results. This goal has been achieved well for Failed to parse (Missing texvc executable; please see math/README to configure.): M_L , Failed to parse (Missing texvc executable; please see math/README to configure.): M_s , and Failed to parse (Missing texvc executable; please see math/README to configure.): M_w .^[6][7] The Failed to parse (Missing texvc executable; please see math/README to configure.): m_b scale gives somewhat different values than the other scales. The reason for so many different ways to measure the same thing is that at different distances, for different hypocentral depths, and for different earthquake sizes, the amplitudes of different types of elastic waves must be measured.

Failed to parse (Missing texvc executable; please see math/README to configure.): M_L is the scale used for the majority of earthquakes reported (tens of thousands) by local and regional seismological observatories. For large earthquakes worldwide, the moment magnitude scale is most common, although Failed to parse (Missing texvc executable; please see math/README to configure.): M_s is also reported frequently.

The seismic moment, Failed to parse (Missing texvc executable; please see math/README to configure.): M_o , is proportional to the area of the rupture times the average slip that took place in the earthquake, thus it measures the physical size of the event. Failed to parse (Missing texvc executable; please see math/README to configure.): M_w is derived from it empirically as a quantity without units, just a number designed to conform to the Failed to parse (Missing texvc executable; please see math/README to configure.): M_s scale.^[8] A spectral analysis is required to obtain Failed to parse (Missing texvc executable; please see math/README to configure.): M_o , whereas the other magnitudes are derived from a simple measurement of the amplitude of a specifically defined wave.

All scales, except Failed to parse (Missing texvc executable; please see math/README to configure.): M_w , saturate for large earthquakes, meaning they are based on the amplitudes of waves which have a wavelength shorter than the rupture length of the earthquakes. These short waves (high frequency waves) are too short a yardstick to measure the extent of the event. The resulting effective upper limit of measurement for Failed to parse (Missing texvc executable; please see math/README to configure.): M_L

is about 6.5 and about 8 for Failed to parse (Missing texvc executable; please see math/README to configure.): M_s

.^[9]

New techniques to avoid the saturation problem and to measure magnitudes rapidly for very large earthquakes are being developed. One of these is based on the long period P-wave,^[10] the other is based on a recently discovered channel wave.^[11]

The energy release of an earthquake,^[12] which closely correlates to its destructive power, scales with the ³⁄₂ power of the shaking amplitude. Thus, a difference in magnitude of 1.0 is equivalent to a factor of 31.6 (Failed to parse (Missing texvc executable; please see math/README to configure.): =({10^{1.0}})^{(3/2)} ) in the energy released; a difference in magnitude of 2.0 is equivalent to a factor of 1000 (Failed to parse (Missing texvc executable; please see math/README to configure.): =({10^{2.0}})^{(3/2)}

) in the energy released.[13] The elastic energy radiated is best derived from an integration of the radiated spectrum, but one can base an estimate on Failed to parse (Missing texvc executable; please see math/README to configure.): m_b

because most energy is carried by the high frequency waves.

Richter magnitudes[link]

The Richter magnitude of an earthquake is determined from the logarithm of the amplitude of waves recorded by seismographs (adjustments are included to compensate for the variation in the distance between the various seismographs and the epicenter of the earthquake). The original formula is:^[14]

Failed to parse (Missing texvc executable; please see math/README to configure.): M_\mathrm{L} = \log_{10} A - \log_{10} A_\mathrm{0}(\delta) = \log_{10} [A / A_\mathrm{0}(\delta)],\

where A is the maximum excursion of the Wood-Anderson seismograph, the empirical function A₀ depends only on the epicentral distance of the station, Failed to parse (Missing texvc executable; please see math/README to configure.): \delta . In practice, readings from all observing stations are averaged after adjustment with station-specific corrections to obtain the M_L value.

Because of the logarithmic basis of the scale, each whole number increase in magnitude represents a tenfold increase in measured amplitude; in terms of energy, each whole number increase corresponds to an increase of about 31.6 times the amount of energy released, and each increase of 0.2 corresponds to a doubling of the energy released.

Events with magnitudes greater than about 4.6 are strong enough to be recorded by a seismograph anywhere in the world, so long as its sensors are not located in the earthquake's shadow.

The following describes the typical effects of earthquakes of various magnitudes near the epicenter. The values are typical only and should be taken with extreme caution, since intensity and thus ground effects depend not only on the magnitude, but also on the distance to the epicenter, the depth of the earthquake's focus beneath the epicenter, and geological conditions (certain terrains can amplify seismic signals).

(Based on U.S. Geological Survey documents.)^[16]

Great earthquakes occur once a year, on average. The largest recorded earthquake was the Great Chilean Earthquake of May 22, 1960, which had a magnitude of 9.5 on the moment magnitude scale.^[17]

Examples[link]

The following table lists the approximate energy equivalents in terms of TNT explosive force – though note that the earthquake energy is released underground rather than overground.^[18] Most energy from an earthquake is not transmitted to and through the surface; instead, it dissipates into the crust and other subsurface structures. In contrast, a small atomic bomb blast (see nuclear weapon yield) will not simply cause light shaking of indoor items, since its energy is released above ground.

Following, 31.623 to the power of 0 equals 1, 31.623 to the power of 1 equals 31.623 and 31.623 to the power of 2 equals 1000. Therefore, an 8.0 on the Richter scale releases 31.623 times more energy than a 7.0 and a 9.0 on the Richter scale releases 1000 times more energy than a 7.0.

• Quakes using the more modern magnitude scales will denote their abbreviations: Failed to parse (Missing texvc executable; please see math/README to configure.): M_W and Failed to parse (Missing texvc executable; please see math/README to configure.): M_S . Those that have no denoted prefix are Failed to parse (Missing texvc executable; please see math/README to configure.): M_L . Please be advised that the magnitude "number" (example 7.0) displayed for those quakes on this table may represent a significantly greater or lesser release in energy than by the correctly given magnitude (example Failed to parse (Missing texvc executable; please see math/README to configure.): M_W ).

Magnitude empirical formulae[link]

These formulae are an alternative method to calculate Richter magnitude instead of using Richter correlation tables based on Richter standard seismic event (Failed to parse (Missing texvc executable; please see math/README to configure.): M_\mathrm{L} =0, A=0.001mm, D=100km).

The Lillie empirical formula:

Failed to parse (Missing texvc executable; please see math/README to configure.): M_\mathrm{L} = \log_{10}A - 2.48+ 2.76\log_{10}\Delta

Where:

• A is the amplitude (maximum ground displacement) of the P-wave, in micrometers, measured at 0.8 Hz.
• Failed to parse (Missing texvc executable; please see math/README to configure.): \Delta

is the epicentral distance, in km.

For distance less than 200km:

Failed to parse (Missing texvc executable; please see math/README to configure.): M_\mathrm{L} = \log_{10} A + 1.6\log_{10} D - 0.15

For distance between 200km and 600km:

Failed to parse (Missing texvc executable; please see math/README to configure.): M_\mathrm{L} = \log_{10} A + 3.0\log_{10} D - 3.38

where A is seismograph signal amplitude in mm, D distance in km.

The Bisztricsany (1958) empirical formula for epicentral distances between 4˚ to 160˚:

Failed to parse (Missing texvc executable; please see math/README to configure.): M_\mathrm{L} = 2.92 + 2.25 \log_{10} (\tau) - 0.001 \Delta^{\circ}

Where:

• Failed to parse (Missing texvc executable; please see math/README to configure.): M_\mathrm{L}

is magnitude (mainly in the range of 5 to 8)

• Failed to parse (Missing texvc executable; please see math/README to configure.): \tau

is the duration of the surface wave in seconds

• Failed to parse (Missing texvc executable; please see math/README to configure.): \Delta

is the epicentral distance in degrees.

The Tsumura empirical formula:

Failed to parse (Missing texvc executable; please see math/README to configure.): M_\mathrm{L} = -2.53 + 2.85 \log_{10} (F-P) + 0.0014 \Delta^{\circ}

Where:

• Failed to parse (Missing texvc executable; please see math/README to configure.): M_\mathrm{L}

is the magnitude (mainly in the range of 3 to 5).

• Failed to parse (Missing texvc executable; please see math/README to configure.): F-P

is the total duration of oscillation in seconds.

• Failed to parse (Missing texvc executable; please see math/README to configure.): \Delta

is the epicentral distance in kilometers.

The Tsuboi, University of Tokio, empirical formula:

Failed to parse (Missing texvc executable; please see math/README to configure.): M_\mathrm{L} = \log_{10}A + 1.73\log_{10}\Delta - 0.83

Where:

• Failed to parse (Missing texvc executable; please see math/README to configure.): M_\mathrm{L}

is the magnitude.

• Failed to parse (Missing texvc executable; please see math/README to configure.): A

is the amplitude in um.

• Failed to parse (Missing texvc executable; please see math/README to configure.): \Delta

is the epicentral distance in kilometers.

See also[link]

• Earthquake
• Largest earthquakes by magnitude
• Seismic scale
• Seismite
• Mercalli intensity scale
• Moment magnitude scale
• Japan Meteorological Agency seismic intensity scale
• Order of magnitude
• Rohn Emergency Scale for measuring the magnitude (intensity) of any emergency

References[link]

External links[link]

• IRIS Real-time Seismic Monitor of the Earth
• USGS: magnitude and intensity comparison
• USGS: Earthquake Magnitude Policy
• USGS: 2000–2006 Earthquakes worldwide
• USGS: 1990–1999 Earthquakes worldwide
• Alaska Railroad Earthquake with a table of yield-to-magnitude relations.

Look up magnitude in Wiktionary, the free dictionary.

Magnitude may refer to:

In mathematics:

• Magnitude (mathematics), the relative size of a mathematical object
• Magnitude (vector), a term for the size or length of a vector
• Scalar (mathematics), a quantity defined only by its magnitude
• Euclidean vector, a quantity defined by both its magnitude and its direction
• Order of magnitude, the class of scale having a fixed value ratio to the preceding class

In astronomy:

• Magnitude (astronomy), a measure of brightness and brightness differences used in astronomy
  • Apparent magnitude, the apparent brightness of a celestial object as observed from Earth
  • Absolute magnitude, the brightness of a celestial object corrected to a standard luminosity distance
  • Photographic magnitude, the brightness of a celestial object corrected for photographic sensitivity, symbol m_pg
• Magnitude of eclipse or geometric magnitude, the size of the eclipsed part of the Sun during a solar eclipse or the Moon during a lunar eclipse

As an earthquake unit of measure:

• Richter magnitude scale, a measure of the energy of an earthquake
• Moment magnitude scale, an alternative to the Richter scale for measuring earthquakes
• Surface wave magnitude

In popular culture:

• Magnitude, a recurring character from the television series Community

This disambiguation page lists articles associated with the same title. If an internal link led you here, you may wish to change the link to point directly to the intended article.

This biographical article needs additional citations for verification. Please help by adding reliable sources. Contentious material about living persons that is unsourced or poorly sourced must be removed immediately, especially if potentially libelous or harmful. (May 2010)

The Basics
The Basics at the Oxford Art Factory, 2010
Background information
Origin	Melbourne, Australia
Genres	Rock
Years active	2002–present
Labels	Independent, Albert Records
Associated acts	Gotye, Down Hills Home, Dog With Wheels, Blood Red Bird
Website	The Basics Official Website
Members
Wally De Backer Kris Schroeder Tim Heath
Past members
Michael Hubbard
Notable instruments
Lead guitar, drums, bass guitar.

The Basics ( /ˈbæzɪtʃ/ BAZZ-ich) are a three-piece band from Melbourne, Australia, formed by Wally De Backer and Kris Schroeder in 2002. Their style has been described as anything from 'indie-pop' to 'rock'n'roll' to 'pop-rock', though their records show they span a wide range of genres, including reggae, ska, country, and electro-pop. They are "recognised as one of Australia's hardest-working bands".^[1]

With close to 1000 shows in their ten-year career, their live performances are well-known for their sense of humour and energy.^[2]

Formation[link]

The Basics were formed after Kris met Wally at a party in Melbourne.^[3] The event was to see off the young aspiring producer, who was about to depart for Los Angeles, and together with a number of musician friends, the two jammed on some blues-rock standards. Later that night, they bonded over a mutual love of The Beatles, 70s and 80s cartoon theme songs and old Sierra adventure games.

Initially, they played around Melbourne as an acoustic guitar/drums combo, starting at The Opposition in Frankston and the House of Fools in Footscray, where in late 2002 they met Michael Hubbard and later invited him to join them on electric guitar.^[4] Though lacking any real experience with the instrument, Kris willingly purchased his first bass guitar, and the trio was born. During this time, the group start performing songs with more complicated three-part harmony.

During late 2002 and early 2003, The Basics recorded and released an album called Get Back through MGM Distribution. They began what was to become regular tours of the East and West coasts of Australia.

2004-2005: Current lineup[link]

Tim Heath joined the group in June 2004, after Michael decided to pursue his solo career, which has included being one half of Down Hills Home.^[4] Tim was reportedly the only person to reply to an advertisement in Melbourne's Beat Magazine looking for a new guitarist. Tim apparently answered the advertisement - which said the applicant "must have a love of 50s and 60s rock'n'roll" - thinking that he would be meeting "a couple of old guys to play with on the weekends over some beers". They soon recorded For Girls Like You.

The Basics in 2005 continued to tour and play small festivals, and after releasing For Girls Like You through MGM Distribution, they departed for a national tour of Australia, which lasted for two months and took them to every Australian state and territory. Stuart Padbury, a young Melbourne sound engineer, joined them on much of this tour. On returning, the band began demonstrating songs for a new album.

2006-2009: Touring and soundtracks[link]

In 2006, The Basics began recording what was to become known as Stand Out/Fit In. Taking several months, it was not completed until the end of the year, despite intentions to have it released in June. Instead, they held a successful 'album preview', where each of the tracks was demonstrated in 'rough form' accompanied by a music video for each (produced by Melbourne photographic artist James Bryans). The band also talked about the origins of the songs. This event brought a lot of attention to the band for the idea's originality. They pre-released a radio single 'Just Hold On' from the album. The band were invited to play the hugely popular Homebake Festival in Sydney, where they received a great response, after being introduced onto the stage by a short stocky Asian guy with big calves ("one of the highlights" wrote The Daily Telegraph).

In 2007, the band departed on a tri-state residency which saw them play Melbourne, Sydney and Brisbane every week for the month of April - a bold move which brought further attention to the band for its original idea.^[5] Riding on the wave of this tour, Schroeder, De Backer and Heath departed on their first overseas tour which saw them performing 26 shows around Japan, Norway and the United Kingdom.^[6] They also toured twice more up the East Coast, one of which was with popular Japanese band The Bawdies. Their song 'Rattle My Chain' was used in a series of commercials for Volvo Australia. The song 'Hey There!' featured in the British film The Bank Job - starring Jason Statham - and was used as the backing for a February 2007 short film directed by Tim Longhurst called The Rip. Their song 'Better' was featured in a surfing documentary about the invention of the shortboard in 1967.

In 2008, the band appeared on Australia's Channel 9 for Australia Day celebrations, performing two of their songs - 'Just Hold On' and 'Hey There!' - to an estimated audience of 2 million. Securing an Australian Government grant, they embarked on a two-month tour of Australia, specifically targeting "culturally underprivileged groups" in rural and regional schoolchildren and Indigenous communities. The programme had them holding masterclasses and performing alongside Indigenous groups in the remote Northern Territory and Queensland.^[7][8] Their initiative also had them raising money for the charity Lifeline^{[disambiguation needed ]}, their contribution to which was recognised with a plaque at the end of the tour. Season two of Californication starring David Duchovny featured their cover of the classic 'Have Love, Will Travel', most famously covered by 'The Sonics'.

In 2009, The Basics for the first time enjoyed the support of Australian radio network Triple J, which had reportedly snubbed the band's previous material.^[9] The singles 'With This Ship' and 'Like A Brother' were added to the station's playlist, and momentum carried The Basics overseas for a second tour of the United Kingdom and Norway, and also a series of shows in Dublin, Ireland. They were joined by the longtime front-of-house engineer Stuart Padbury, who had been mixing them since 2005. The band was often seen in the Grafton Street Mall in Dublin, busking to promote their concerts there. Their second show in Oslo, Norway, saw the band perform with Hot Tub, one of the members of the Norwegian boy band "Boyzvoice", in his first performance for several years. Season Eight of Scrubs featured the song 'Lookin' Over My Shoulder'.

Despite all this promise, the band's album Keep Your Friends Close - produced and part-recorded by Peter Cobbin at London's Abbey Road Studios - though enjoying many favourable reviews,^{[10][11][12][13]} failed to impress Richard Kingsmill, music director of Triple J. This effectively ended the band's apparent upward spiral and the resulting album launch tour was reportedly "trying".

2010: Hiatus and live album[link]

In 2010, following the band's fourth stint at the Tamworth Country Music Festival, and the recording of a yet-unreleased live album, an indefinite hiatus was announced on the band's websites. This was in part due to the impending release of a new album produced by Wally for his Gotye project, and also to reported tensions within the band following the previous year's disappointments.

However, this hiatus was soon broken with a two-month residency at the Northcote Social Club in Melbourne, which saw an apparent return to form.^[14] The band's EP "Wait For You" enjoys airplay on Triple J.^[15] The Basics also played a one-off show at Sydney's Oxford Art Factory.^[16]

On 20 August 2010, The Basics released their fourth LP /ðəˈbæzɪtʃ/, available free and exclusively from their website for digital download^[17]. The band had reportedly moved to expand their listenership through this free giveaway, though 300 "Deluxe" CD/vinyl versions have been printed. /ðəˈbæzɪtʃ/ was recorded at the Northcote Social Club on 6 February, "in front of a live studio audience", and like the previous record, was mixed by Peter Cobbin at Abbey Road Studios. Technically a self-titled album, the phonetics spell out the accurate pronunciation of the band’s name. Kris Schroeder: "For years we’ve worked at bringing our live energy into the studio and thus far it’s been a bit hit-and-miss. Our trick this time was to pull a switcheroo and bring the studio to us instead; the result is the best and closest to us we’ve sounded yet."

Melbourne thespian and Dog With Wheels bassist David Bramble - friends with Heath from university days - has occasionally joined the band on tour, playing keys, often while sporting a large moustache. Other guests have included Jake Mason (saxophone), also of Cookin' on 3 Burners and The Bamboos^{[disambiguation needed ]}, Gideon Brazil (saxophone, flute), Simon Imrei (guitar and vocals) and Monty MacKenzie (saxophone).

Covers have often made an appearance from various sources: to date, some of the bands covered have been Cream, The Kinks, The Rolling Stones, The Police, Neil Young, Bob Dylan, New Kids on the Block, Richard Berry, Sonny Curtis and The Crickets, JJ Cale, Harry Nilsson, Bill Scott, Ryan Adams and The Coasters (via The Beatles for their cover of Three Cool Cats).

Members[link]

Current

• Wally De Backer - drums, vocals (2002-present)
• Kris Schroeder - bass, vocals (2002-present)
• Tim Heath - guitar, vocals (2004-present)

Former

• Michael Hubbard - guitar, vocals (2002-2004)

Discography[link]

Albums[link]

• Get Back (15 January 2004)
• Stand Out/Fit In (5 May 2007)
• Keep Your Friends Close (25 September 2009)
• /ðəˈbæzɪtʃ/ (20 August 2010)

EP[link]

• For Girls Like You (11 July 2005)
• Lookin' Over My Shoulder (10 February 2007)
• Like A Brother (5 June 2009)
• Wait For You (21 May 2010)

Singles[link]

• Call It Rhythm & Blues (20 August 2004)
• Just Hold On
• With This Ship (22 February 2009)

Upcoming projects[link]

The band is taking a three year hiatus, with an announced return to the stage together in early 2014. Wally De Backer launched Making Mirrors under his Gotye act in August 2011, Tim Heath will be touring and recording with Blood Red Bird, and Kris Schroeder recorded a solo EP titled, Patience in the Face of Control, before leaving Australia to work with the Red Cross in Kenya for a two year sabbatical.

References[link]

External links[link]

• Official Website
• Myspace Website