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The time history is the sequence of values of any time-varying quantity (such as a ground motion measurement) measured at a set of fixed times. Also termed time series.

The slip rate is how fast the two sides of a fault are slipping relative to one another, as determined from geodetic measurements, from offset man-made structures, or from offset geologic features whose age can be estimated. It is measured parallel to the predominant slip direction or estimated from the vertical or horizontal offset of geologic markers.

Soil profile in hills of Manisa Province, Turkey, showing a distinct horizon of accumulated red-purple metallic (manganese and/or iron?) oxides.

The source is the term for the released forces that generate acoustic or seismic waves, also called the earthquake source.

A P wave, or compressional wave, is a seismic body wave that shakes the ground back and forth in the same direction and the opposite direction as the direction the wave is moving.

Person sitting and overlooking valley of snow-topped mountains with clouds in between mountains 

Diagram of period.  The period is the time interval required for one full cycle of a wave.

Plate Tectonics is the theory supported by a wide range of evidence that considers the earth's crust and upper mantle to be composed of several large, thin, relatively rigid plates that move relative to one another. Slip on faults that define the plate boundaries commonly results in earthquakes.

Ripples on a pond are attenuated as they move away from the source. Q is the inverse of attenuation. A high Q means a low attenuation.

Geologic time scale showing eras, periods, and notable events in terms of millions of years ago.

A stress vs time graph showing fault strength and an offset across fault vs time graph 

The reflection is the energy or wave from an earthquake that has been returned (reflected) from an boundary between two different materials within the earth, just as a mirror reflects light.

Refraction is (1) the deflection, or bending, of the ray path of a seismic wave caused by its passage from one material to another having different elastic properties. (2) bending of a tsunami wave front owing to variations in the water depth along a coastline.

Seismicity of Hawaii: earthquakes M>5 from the 1840-1899, 1900-1959, 1960-2019 catalogs shown separately. While earthquake activity remains high today, it seems to have decreased over the past 60 years, which could be related to less volcanic activity at Mauna Loa. 

Figure 2.

Figure 1. Chance of minor or greater damaging earthquake shaking in the next 100 years. Population exposure estimates are rounded to the nearest 1000. 

Debris flow caused by intense rainfall from Tropical Storm Fred in August 2021. Haywood County, NC. 

2018 Long-term National Seismic Hazard Map. Earthquake hazard map showing peak ground accelerations having a 2 percent probability of being exceeded in 50 years, for a firm rock site.  The map is based on the most recent USGS models for the conterminous U.S.

Debris flow deposits caused by intense rainfall in April 2020 block a highway in Macon County, NC. 

Debris flow caused by intense rainfall in April 2020 in Macon County, NC. 

Damage from a major post-wildfire landslide that occurred on 25 December 2003 near Devore, San Bernardino County as a result of the Old/Grand Prix fires that ran through the San Bernardino Mountains.