قالب:M

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  • For the "small letter m with dot below" please use the HTML encoding "&7747;", or the Unicode "1E43" code.

Given a valid code (see table), outputs an earthquake magnitude scale label, either the generic M, or a subtype (such as Mw  or mbLg ), conformable with the labels most commonly used by the major seismological authorities. The article is automatically added to a tracking category. Optionally adds a value or relation, identifies a source, or links to explanatory text at Seismic scale.

Usage

  • {{ M | <code> | <value or relation> | src = <source> | link=y }}

A valid "code" is required (see table), other parameters are optional.

Examples

Label only:

  • {{M|w}} → Mw

Label with wikilink to explanatory text (useful for first mention):

  • {{M|jma|link=y}} → MJMA
  • {{M|t|link=y}} → Mt

With a value or range:

  • {{M|b|5.1}} → mb   5.1.
  • {{M|w|6.2 – 6.5}} → Mw   6.2 – 6.5

To show that a magnitude is from a particular catalog or source use |src=:

  • {{M|w|8.1|src=ISC}}, {{M|e|8.8|src=USGS}} → Mw(ISC)  8.1,   Me(USGS)  8.8


There are multiple magnitude scales. To maintain accuracy and avoid error please use the proper code. If you are uncertain, use the special maintenance code "?":

  • {{M|?}} → M

The special code "mag" produces a suitably wikilinked caption for use in tables:

قالب:Hl just because a newspaper or other popular media says "Richter". That is usually incorrect. Earthquake magnitudes reported by the U.S. Geological Survey (USGS) and other seismological authorities now generally use the moment magnitude scale for magnitudes greater than 4.0. While most newspapers and other popular media refer to this as the "Richter" magnitude, this is usually not correct. Richter's original scale, explicitly denoted with the symbol "ML" or "ML" (where "L" indicates "Local"), was developed for measuring the magnitude of earthquakes in the vicinity of southern California. While the "Richter" and moment magnitude scales are similar, they do differ, particularly for larger earthquakes.

In general: where any source specifies magnitude on a scale other than "Richter", or uses "M" (or "m") with one or more other letters (such as ML, Mw, Ms, or mb), that can be relied on; use the table below to match the label and determine the proper code.

Where a newspaper or other popular media refers to the "Richter" scale or magnitude of a recent earthquake it is probably the popular mis-identification of the moment magnitude scale. Best practice is to check with an authoritative source, such as the USGS or the International Seismic Centre (see below). USGS policy is that magnitudes in press releases, indicated as "M", are implicitly moment magnitude. But: if an authoritative source does not actually say "Mw" or "moment magnitude scale", do not use "Mw". If you have a strong basis for believing that is meant, use the "dot" code to indicate an implicit Mw. E.g.: {{M|.|5.7}}.

If you are not sure of the scale, use {{M|?}}.

Data sources

Newspapers and other mass media are not reliable sources for earthquake magnitudes. It is preferable that earthquake magnitudes always be obtained from authoritative sources, such as the following.

  • Latest Earthquakes. In most cases there is an initial report within 30 minutes of all magnitude 5.0+ earthquakes globally, and magnitude 4.0+ earthquakes within the contiguous U.S.
  • Significant Earthquakes, Past 30 Days. This information is updated as more data becomes available.
  • Significant Earthquakes Archive. Includes criterion for "significant".
  • The Preliminary Determination of Epicenters (PDE) Bulletin. A weekly archive of earthquakes. Note: these are NOT updated. Use the ISC catalog (below) for the best data of non-recent events. (Source id: PDE.)
  • The Centennial Catalog (Engdahl and Villaseñor, 2002): A definitive list of significant earthquakes recorded from 1900 to 2008, with some earlier historical and pre-historical events, and the best estimate of their magnitude. This includes most magnitude 5.5+ events since 1964. (Source id: E&V.)

Other authoritative sources may be found through the USGS lists of catalogs and Geophysics Institutions Throughout the World. When using such a source please identify it in a note.

An earthquake's magnitude may be given on different scales because what they actually measure is affected differently. Estimates of magnitude may differ between networks and across time because of differences or changes in how the seismograms are read and the data processed. For details see the NMSOP-2 documentation (below).

It is recommended that the first use or mention of a magnitude scale in an article use the |link=y parameter to wikilink it to a suitable explanation.

Table of codes

These are the most commonly found scales of earthquake magnitude. Any scale not found in this table is mostly likely one of the following:

  • An intensity scale. See Seismic scale for explanation. This template does not cover intensity scales.
  • A regional (or "local") scale used by some particular seismic network (or country). In general it is preferable to use one of the better known scales from the table. Exceptions are for historical reports; you will need to explicitly format as appropriate. If the scale has been properly calibrated (see MNSOP-2, Chapter 3, §3.2.4.3, p. 65) then "L" may be appropriate, along with the |src= parameter.
  • A technical scale. While these might come up in an article related to seismology, they are not appropriate for general description of earthquakes. If needed, please format appropriately. On first use be sure to add a footnote explaining the scale.

Be careful to distinguish upper- and lower-case "M/m", "B/b", "L/l", and "I/i". Other than that case is generally not significant, nor italicization or subscripting.

The following examples are representative, not comprehensive.

Labels and codes for various earthquake magnitude scales
As seen in sources WP Code Mag. scale Cat. # Comments
IASPEI NMSOP USGS ISC BSSA
-- -- -- -- -- M ? Unspecified M_? 1 WP: scale is unspecified or indeterminate.
-- -- -- -- -- M ?? Needs verification M_?? 0 WP: the scale and/or magnitude needs verification.
-- -- -- -- -- M R? Dubious "Richter" M_R? 0 WP: "Richter" scale is asserted, but dubious.
UK Muk uk Unknown M_uk 0 Source says "unknown" scale. Might be 1954 MGR mag.; see link.
ML Ml ML ML ML ML l Local ("Richter") M_L 0 §4.1 "Local" to Southern Calif. Adapted for other regions, but not necessarily comparable.
MJMA Mj MJMA MJMA jma JMA "Local" mag. M_jma 0 §3.2.4.7 Japanese Meteorological Agency. Also MJ, but not Mw(JMA).
M0 [[Seismic magnitude scales#M0|Mقالب:Ssub]] 0 seismic moment M_0 0 "M zero". Basis of Mw. In Newton-meters (Joules) or dyne-centimeters
M M M . moment mag. M_w. 0 dot: implicit Mw.
Mw Mw Mw Mw w moment mag. M_w 44 §4.7 Preferred when available.
Mwb Mwb wb M_wb 0 Mw calculated from body-waves
Mwc Mwc wc M_wc 0 Mw from centroid moment
Mww Mww ww M_ww 0 Mw from W-phase centroid
Mwr Mwr wr M_wr 0 Mw at regional distance
Mwp Mwp wp M_wp 0 Mw from broadband P-waves §3.2.8.2
Mwpd Mwpd wpd M_wpd 0 Mwpd w/ duration §3.2.8.3
Mi Mi i USGS synonym for Mwp M_i 0 Lower-case "i" only.
mb mb mb Mb mb mb b body-wave, short-period M_b 0 §4.3 Case sensitive: use "b"
mB mB -- M Mb(BB) mB B body-wave, broadband M_B 0 §4.2 Case sensitive: use "B"
mB_BB mB -- M Mb(BB) mBBB bbb body-wave, broadband M_Bbb 0 §4.2
mb_Lg mbLg mb_Lg, MLg mb(Lg) mbLg blg mb from Lg wave M_bLg 0 §3.2.4.4; §4.6 North America east of the Rocky Mountains, and other cratons
Mn MN mN n Nuttli (1973) M_N 0 §3.2.4.4; §4.6 Same as mbLg
mBc mBc bc Cumulative body-wave M_Bc 0 §3.2.8.1
MS Ms s surface wave M_s 5 §4.4 Generic
Ms_20 Ms Ms Ms Ms(20) Ms20 s20 surface-wave 20s M_s20 0 §4.4 Short period (20 sec.) surface waves
Ms_BB Ms -- Ms Ms(BB) MsBB sbb broadband surface wave M_sbb 0 §4.5
Mz z surface wave, vertical M_z 0
MS7 Ms7 s7 surface wave (Chinese) M_s7 0
MGR MGR MGR gr Gutenberg-Richter M_gr 0 1954 G-R version of Ms
MR MR r Rothe M_r 0 Not "Richter"! Ms per Rothe 1969
Mc Mc Mc c coda length M_c 0 §3.2.4.5
Md MD MD Md d duration M_d 0 §3.2.4.5 Many variants
Mt t tsunami mag. M_t 0 §3.2.6.7 Used by PTWC
Mm Mm m mantle mag. M_m 0 §3.2.8.5 Used by PTWC
Me e energy mag. M_e 0 §3.2.7.2
K M(K) k K-class mag. M_K 0 §3.2.4.5; IS 3.7 Former Soviet Union, Cuba, etc. Several regional variants.
Mms ms macroseismic M_ms 0 §3.2.6.6 Generic mag. estimated from macroseismic effects
FA Mfa Mfa fa mb from felt-area M_fa 1 Multiple methods.
MLa Mla la ML from felt-area M_la 0 ML estimated from intensity reports; Calif. and Hawaii
MI MI I ML from intensity M_I 0 Upper-case "I" only.

Examples of use are from the International Association of Earth Physics and Interior (IASPEI), the first edition of the New Manual of Seismological Practice (NMSOP)(the second edition follows the IASPEI), the United States Geological Survey (USGS) National Earthquake Information Center (NEIC), the International Seismological Centre (ISC), and the Bulletin of the Seismological Society of America (BSSA), as summarized in table 3 of the IASPEI/MNSOP-2 Information Sheet 3.3. Additional magnitude scales from Chapter 3 of MNSOP-2, ISC documentation, the USGS, and a review of the literature. Section numbers under "Comments" are for either Chapter 3, or Information Sheet 3.3

The nomenclature style implemented here is adapted from IASPEI/MNSOP-2 Information Sheet 3.3. This style differs from IASPEI style mainly in using subscripts rather than underscores, and from BSSA style mainly in not using parentheses.

"Cat.": the Categories for tracking use of these various scales. "#" is the number of pages in that category (when last checked).

Principal references on usage are:

These sources also have extensive discussion and references on the derivation and comparison of the various scales.

See also