| IASPEI | NMSOP | USGS | ISC | BSSA | WP | Code | Magnitude scale | Cat. | Comments and references | |
|---|---|---|---|---|---|---|---|---|---|---|
| M | ? | Unspecified mag. scale | M_? | |||||||
| ML | Ml | ML | ML | ML | → | ML | l | Local ("Richter") | M_L | §4.1 "Local" to Southern Calif.; adapted for other localities |
| M | → | M | . | moment | M_w | dot: implicit w | ||||
| Mw | Mw | → | Mw | w | moment | M_w | §4.7 Preferred when available. | |||
| M0 | 0 | scalar moment | M_0 | "M sub zero". Basis of Mw | ||||||
| Ms | s | surface-wave (generic) | M_s | §4.4 | ||||||
| Ms_20 | Ms | Ms | Ms | Ms(20) | → | M20 | 20 | surface-wave 20s | M_20 | §4.4 surface waves with 20 sec. period. Identical to NEIC Ms
since 1975 |
| Ms_BB | Ms | -- | Ms | Ms(BB) | → | mB | bb | broad-band body-wave | M_bb | §4.2 |
| mb | mb | mb | Mb | mb | → | Mb | b | short-period body-wave | M_b | §4.3 subset of Ms |
| Mz | z | surface wave (vertical) | M_sz | |||||||
| mb_Lg | mbLg | Lg | MN | mb(Lg) | → | Mb(Lg) | lg | Lg wave | M_Lg, M_N | §4.6 Nuttli. Used in the CEUS catalog for central and eastern U.S. |
| Mc | c | coda length | M_c | |||||||
| Md | d | duration | M_d | |||||||
| Mk | k | Russian "Energy Class" | M_k |
** Forms used by various agencies is incomplete. **
Nomenlature of the IASPEI.International Association of Earth Physics and Interior (2012), the New Manual of Seismological Practice (NMSOP, 2002), the United States Geological Survey National Earthqauke Information Center, the International Seismological Centre, and the Bulletin of the Seismological Society of America, summarized in table 3 of the IASPEI's Information Sheet 3]. Section numbers refer to the Information Sheet.
The nomenclature implemented here is adapted from IASPEI Information Sheet 3. It differs from IASPEI style in using subscripts, and from BSSA style in not using parentheses. Additional magnitude scales from ISC documentation.
"Cat." are the Categories for tracking use of these various scales.