Low velocity layer

{
  "id": "MLC-T-OAG-002226",
  "term": "Low velocity layer",
  "field": "Oil and gas",
  "definitions": [
    "A zone of unconsolidated material near the Earth's surface, such as soil and weathered rock, characterized by a significantly lower seismic velocity than the underlying bedrock. This layer, also called the weathering layer, causes distortions and time delays in seismic waves that must be corrected during data processing. The thickness and velocity of this layer are determined using refraction surveys or uphole surveys to calculate static corrections.",
    "A near-surface layer of unconsolidated or weathered material, such as soil or alluvium, through which seismic waves travel at a significantly reduced speed compared to underlying rock formations. This layer can attenuate seismic energy and distort reflections, requiring careful processing to obtain accurate subsurface images. Its thickness and velocity are determined by refraction seismic surveys."
  ],
  "subject": [
    "Geophysics",
    "Geology"
  ],
  "url": "https://mlchart.com/terminology/oil-and-gas/low-velocity-layer/"
}