Earthquakes

Earthquakes on TerraPulse are organized into the eq Eventdex and its four magnitude-band siblings — one slot per event, each a measured record of a quake that actually happened, sourced from the U.S. Geological Survey. No estimates, no forecasts.

The dexes

The data lives across five parallel Eventdexes, split by magnitude so a study can pull exactly the population it needs. Counts are live and grow with every fetch:

Dex	Holds	Events
`eq`	Notable events (the headline seismicity feed)	13,870
`eq_mag_3_45`	Light quakes, magnitude 3–4.5	65,643
`eq_mag_1_2`	Minor quakes, magnitude 1–2	13,186
`eq_mag_lt1`	Micro quakes, below magnitude 1	4,936
`eq_mag_2_3`	Small quakes, magnitude 2–3	4,269

Together, about 102,000 measured earthquakes, the record reaching back to 1973 and updating continuously as new events are reported.

Provenance

Every event traces to the USGS Earthquake Hazards Program, which monitors seismic activity worldwide through a network of more than 2,000 stations and publishes each event within minutes. That single source is registered against all five dexes, so any record on TerraPulse carries a direct line back to the originating USGS observation.

What's in a record

Each event slot carries:

Magnitude — on the moment/Richter scale
Location — latitude, longitude, and depth in kilometers
Time — origin time, UTC
PAGER alert level — green, yellow, orange, or red, by estimated impact
Tsunami flag — whether the event could generate a tsunami
Felt reports — the count of "Did You Feel It?" responses

Magnitude, briefly

Range	Class	Effects
< 2.0	Micro	Not felt; recorded by instruments
2.0–3.9	Minor	Often felt, rarely damaging
4.0–4.9	Light	Noticeable shaking, minor damage
5.0–5.9	Moderate	Can damage weak structures
6.0–6.9	Strong	Destructive in populated areas
7.0+	Major/Great	Serious damage over large areas

Explored in

These dexes are the measured backbone of several TerraPulse investigations:

Does the Moon Trigger Strong Earthquakes? — 53 years of the world's largest quakes
The Cascadia Swarm
The Reno Earthquake Swarm
The Kermadec Doublet