#magnitude

Earthquake-magnitude seismology as an API, computed locally and deterministically. The energy endpoint computes the radiated seismic energy released by an earthquake of a given magnitude using the Gutenberg-Richter relation, log10(E) = 1.5·M + 4.8 with E in joules, and converts it to a TNT equivalent in tons and kilotons (one ton of TNT ≈ 4.184×10⁹ J), with a felt/damage classification. The compare endpoint quantifies how much bigger one quake is than another: each magnitude unit means about ten times the ground-motion amplitude on a seismograph and about 31.6 times (10^1.5) the energy, so it returns both the amplitude ratio and the energy ratio between two magnitudes. The moment-magnitude endpoint converts between the seismic moment M0 (in newton-metres, M0 = rigidity × rupture area × slip) and the moment magnitude with the Hanks-Kanamori relation Mw = (2/3)·log10(M0) − 6.07, in either direction. Magnitudes are dimensionless, energy is in joules and seismic moment in newton-metres. Everything is computed locally and deterministically, so it is instant and private. Ideal for seismology-education, disaster-modelling, insurance, structural-risk and science app developers, earthquake-energy and magnitude tools, and STEM teaching. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is the earthquake-magnitude calculator; for real-time and historical earthquake event feeds use an earthquake data API.

api.oanor.com/richter-api

Stellar magnitude and distance maths as an API, computed locally and deterministically. The magnitude endpoint works the distance modulus, m − M = 5·log₁₀(d/pc) − 5 — give any two of the apparent magnitude m, the absolute magnitude M and the distance and it returns the third, with the distance in parsecs, light-years and astronomical units (the absolute magnitude is the apparent magnitude a star would have at 10 parsecs). The flux endpoint applies Pogson's relation to turn a magnitude difference into a brightness ratio, F₁/F₂ = 10^(0.4·(m₂ − m₁)), where five magnitudes is exactly a hundredfold change in brightness — from two magnitudes, a magnitude difference or a ratio. The parallax endpoint converts a parallax angle into a distance, d(pc) = 1 ÷ p(arcseconds), and back, the geometric method behind the parsec itself. Everything is computed locally and deterministically, so it is instant and private. Ideal for astronomy-education, planetarium, stargazing and science app developers, observing and astrophysics tools, and STEM teaching. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is stellar magnitude and distance; for orbital mechanics use an orbital API and for great-circle distances on Earth a geo-distance API.

api.oanor.com/starmagnitude-api