Geology
Geology calculators for earthquake magnitude, rock density, ore grade, and groundwater flow.
Covers seismic energy, sediment size, and slope stability.
Earthquakes, rock properties, groundwater flow and slope stability. 15 calculators spanning field geology and the applied side that engineers use.
Earthquake magnitude is the page most worth running once, because the scale is logarithmic in amplitude and a different power in energy, and almost nobody holds both in mind. One step up the scale is 10 times the ground motion but about 32 times the energy released. So a magnitude 7 is not “a bit worse” than a 6, it releases roughly 32 times more energy, and a magnitude 8 releases about 1,000 times more than a 6. Seismic energy puts that in joules alongside familiar comparisons, which is the only way the numbers land.
Rock density matters more for practical work than it sounds. Granite runs about 2,700 kg per cubic metre and basalt closer to 3,000, so a truckload of the second is over 10% heavier than the first at the same volume. Anyone ordering stone by volume and hauling it by weight needs both numbers.
Darcy flow and transmissivity pages use SI units internally and convert on the way in and out, because hydrogeology is a field where three different unit conventions are in daily use and mixing them is the classic error.
Earthquake Epicenter Intensity Calculator
Estimate Modified Mercalli Intensity (MMI) from earthquake magnitude, epicenter distance and focal depth. Shows felt radius and damage radius.
Plate Tectonic Motion Distance Calculator
Calculate distance moved by a tectonic plate over geologic time. Enter rate and time span to see kilometers, miles, and equivalent landmark distances on Earth.
Aquifer Transmissivity and Hydraulic Conductivity Calculator
Calculate aquifer transmissivity T = K × b, Darcy velocity, and groundwater discharge using standard hydrogeology formulas and pumping test inputs.
Earthquake Magnitude Calculator
Calculate moment magnitude Mw from seismic moment or Richter scale. Returns energy in joules, TNT equivalent in kilotons, and Mercalli intensity description.
Geologic Time Scale Calculator
Look up geologic eon, era, period, and epoch for any age in years, Ma, or Ga. Returns ICS classification and life forms from the Hadean to the Holocene.
Mineral Hardness Identification Guide
Identify minerals by Mohs hardness (1-10), streak color, and luster. Includes household scratch tests for each hardness level and a table of 30 minerals.
Sediment Particle Size Classifier (Wentworth Scale)
Classify sediment by the Wentworth scale from diameter in mm or micrometers. Returns phi (φ) value, class from clay to boulders, and Stokes settling velocity.
Slope Stability Factor of Safety Calculator
Calculate slope factor of safety (FS) via the infinite slope method. Enter angle, cohesion, friction angle, and groundwater depth. FS above 1.5 is stable.
Soil Bearing Capacity Calculator
Calculate ultimate and allowable soil bearing capacity using the Terzaghi method. Enter cohesion, friction angle, and depth to get safe foundation loads.
Darcy's Law Groundwater Flow Calculator
Calculate groundwater flow rate using Darcy's Law. Find seepage velocity, hydraulic gradient, and transmissivity for aquifers and porous media.
Lava Flow Volume Estimator
Calculate lava flow volume in m³ and km³ from length, width, and thickness. Includes effusion rate mode and mass calculation for basalt, andesite, or rhyolite.
Ore Grade and Contained Metal Calculator
Calculate contained metal tonnage from ore grade and ore tonnage. Convert between g/t, ppm, and percent for gold, silver, copper, and other metals in mining.
Rock and Mineral Density Calculator
Look up density of common rocks and minerals. Calculate mass from volume or volume from mass. Compare granite, limestone, basalt, sandstone, and ore densities.
Seismic Energy Calculator
Calculate earthquake energy in joules from magnitude (Mw). See TNT equivalent, Hiroshima bomb equivalents, and comparison to historical earthquakes.
Volcano Eruption Energy Calculator
Calculate the energy released by volcanic eruptions. Convert between Volcanic Explosivity Index (VEI), erupted volume, and equivalent TNT or nuclear bomb yield.