Earth sciences

Seismic stratigraphy

Seismic stratigraphy is a geophysical method that interprets patterns and terminations of seismic reflections in sedimentary strata to build depositional sequences and reconstruct sea-level history.

Seismic surface wave

A seismic surface wave is an elastic wave traveling along the Earth's surface, chiefly Rayleigh and Love waves, which arrive last from earthquakes and do the most damage.

Seismic survey

A seismic survey is a geophysical exploration method that generates seismic waves and records reflected returns, imaging subsurface rock layers for oil, gas, and mineral exploration.

Seismic survey vessel

A seismic survey vessel is a specialized ship that tows acoustic sources and hydrophone streamers to image rock layers beneath the seabed, mainly for offshore oil and gas exploration.

Seismic tomography is an imaging method that reconstructs three-dimensional maps of Earth's interior from seismic wave travel times recorded by seismometer networks, adapted from medical imaging in the 1970s.

Seismic wave

A seismic wave, also called an earthquake wave, is an elastic wave carrying energy from an earthquake or explosion through the Earth or along its surface.

Seismology (σεισμολογία)

Seismology, the study of earthquakes and the Earth's structure through seismic waves, is the principal means of imaging the Earth's interior and underpins earthquake monitoring, hazard assessment, early warning, and nuclear test ban verification.

Seismometer

A seismometer is an instrument that detects ground motion, most commonly the shaking produced by earthquakes, and is the sensing part of a seismograph, first developed in 1890.

Self-potential

Self-potential (SP), also called spontaneous potential, is a passive geophysical survey method measuring natural voltage differences at the Earth's surface, first observed by Robert W. Fox in 1830.

Semi-arid climate

The semi-arid climate, or steppe climate (Köppen BS), is a dry climate intermediate between humid and arid, with aridity index 0.2 to 0.5, supporting grassland and scrub.

Sentinel-6 Michael Freilich

Sentinel-6 Michael Freilich, also known as Jason-CS, is a European-American radar-altimetry satellite launched in November 2020 as the official reference mission for global sea-surface height measurement.

Sequence boundary

A sequence boundary is a surface in sequence stratigraphy separating older from younger depositional sequences, usually an unconformity formed by erosion during falling sea level.

Sequence stratigraphy

Sequence stratigraphy is a stratigraphic method that subdivides sedimentary successions into genetically related units bounded by unconformities and their correlative surfaces, reconstructing depositional history and underpinning petroleum exploration.

Sernageomin

Sernageomin (Servicio Nacional de Geología y Minería) is Chile's national geology and mining service, created in 1980 to map the country's geology, monitor its volcanoes, and regulate mining safety.

Serpentinite

Serpentinite, also called serpentine rock, is a metamorphic rock of serpentine-group minerals formed when water reacts with olivine and pyroxene, named for its mottled green, serpent-like texture.

Serravallian

The Serravallian is a Middle Miocene stage, the fourth of six Miocene stages, spanning roughly 13.82 to 11.62 million years ago between the Langhian and Tortonian.

Servicio Meteorológico Nacional (Argentina)

The Servicio Meteorológico Nacional (SMN) is Argentina's national weather service, founded on 4 October 1872 under President Domingo Sarmiento as the first meteorological service in South America.

Severe tropical storm

A severe tropical storm is a tropical cyclone in the western North Pacific with 10-minute winds of 48 to 64 knots, as classified by Japan.

Severe weather

Severe weather, also called bad weather, is any hazardous atmospheric event threatening life or property, most commonly a thunderstorm with a tornado, large hail, or 58 mph winds.

Severe weather terminology (United States)

Severe weather terminology in the United States is the National Weather Service's tiered system of outlooks, watches, advisories, and warnings, with warnings issued when hazardous weather is imminent.

Severn Cullis-Suzuki

Severn Cullis-Suzuki, also known as Severn Suzuki, is a Canadian environmental activist and author, born in 1979, who spoke at the 1992 Rio Earth Summit at age 12.

Oct 21, 2026

Severny

Severny (volcano 300700) is a late Quaternary shield volcano, 1,936 m, in the northern Sredinny Range of central Kamchatka, Russia; last confirmed eruption 1550 BCE from the Tobeltsen cinder cone on its WSW flank.

SEVIRI

SEVIRI is the primary imaging radiometer on Europe's four Meteosat Second Generation weather satellites, imaging the full Earth disc in 12 channels every 15 minutes.

ShakeAlert

ShakeAlert is the USGS earthquake early warning system for the West Coast, detecting quakes that have already started and alerting people in California, Oregon, and Washington since 2019.

Shale

Shale, also known as shale rock, is a fine-grained laminated sedimentary rock that splits along bedding planes and makes up two thirds of the sedimentary record.

Shamal

The Shamal, Arabic for "north," is a hot, dry, dusty northwesterly wind over Iraq, Kuwait, and the Persian Gulf, lasting one to five days and rarely exceeding 30 mph.

Shared Socioeconomic Pathways

The Shared Socioeconomic Pathways are five scenarios of 21st-century societal, economic, and demographic development created by climate researchers for the IPCC Sixth Assessment Report and CMIP6.

Shear wave splitting

Shear wave splitting is a seismological technique in which anisotropic rock splits a passing shear wave into two waves of different speed and polarization, revealing mantle deformation.