Links to

These are some links to additional information.  
Some of these links are also found in other pages on this site, and are collected here 
with links to other sources of information about seismology, earthquakes and seismic activity, 
and seismometer descriptions and construction.

USGS - Alabama Earthquake Information, including history, institutions, maps, notable and 
recent earthquakes, special topics, and other USGS information.

USGS Seismology and earthquakes education, FAQs, and knowledgebase

University of Nevada Seismological Laboratory

USGS realtime earthquakes report and location map

CERI Southeastern USA realtime earthquakes location map

IRIS (Incorporated Research Institutions for Seismology) realtime worldwide seismic monitor 
and links to additional information on plate tectonics, earthquake headlines, special events, 
and more educational topics

The IRIS USArray Ground Motion Visualization (GMV)
 This illustrates how seismic waves travel away from the earthquake location
by depicting the recorded wave amplitudes at each EarthScope/USArray station location
using colored symbols.  The Vertical-component GMV is produced for USA events 
of magnitude 5.5 or larger and global events of magnitude 6 or larger.
The symbol colors represent the amplitude of the vertical ground motion, as detected by the station's seismometer.
The 3-Component GMV is produced only for events with magnitude 7 and larger use 'tailed' symbols
to show direction and amplitude of the normalized horizontal motion. Symbol colors also represent
the amplitude of the vertical ground motion, as detected by the station's seismometer.

A good collection of information, articles, animations, and facts
about the New Madrid Seismic Zone (NMSZ) origin and history

Seismograph information, construction plans, equipment, and software

Construction article for a Lehman seismometer design

July 1979 Scientific American magazine Lehman seismometer construction article

A brief history and overview of the Inyo Force-Balance Broadband (FBV) seismometer
and two successor instrument designs

Circuit description of the FBV electronics

Calibration procedure for the Inyo FBV seismometer

FBV information including mechanical and electronic drawings, calibration plots,
photographs, and other design details