Science for Planet Earth

braile@purdue.eduwww.eas.purdue.edu/~braile

April 2010

A Decade of Earthquake Monitoring with an Educational Seismograph

Larry BrailePurdue University

SSA Meeting 2010

The AS-1 Seismometer

The AS-1 Seismometer

• Inexpensive (~$600); easy to set up and use• Demonstrate how a seismograph works• “Make your own earthquake”• Monitor earthquakes – local (~M3+), regional

(~M5+), worldwide (~M6.5+)• Connects to IRIS data archiving and analysis

software (written by Alan Jones) on Windows computer; maintain EQ catalog

• Display, filter and analyze seismograms• Calculate epicenter-to-station distance from S-P

times; calculate magnitude

Oil Damping Mechanism

Mass (plus magnet)

Magnet and Coil

Boom

SpringHinge

Magnetic Damping

MechanismMagnetic Damping

Mechanism

The WLIN AS-1 seismometer was installed in basement of home in West Lafayette, Indiana on January 1, 2000 and immediately recorded an earthquake (~M5) from Quebec.

Objectives:

Support the IRIS Seismographs in Schools (SIS) program and use of the seismograph by educators.

Monitor earthquakes and provide sample and comparison data.

Experience with AS-1 and software; test and evaluate seismograph, software and recordings and suggest improvements.

The AmaSeis software to operate the AS-1 was written by Alan Jones. AmaSeis provides display, filtering, analysis and archival.

Calibrated the AS-1 (for calculating magnitudes) with assistance of Bob Hutt (USGS), Tim Long (GT), Alan Jones (Binghamton), John Lahr (USGS).

Ten Years of Recording with the AS-1 Seismometer

Experience with the AS-1 seismograph - Noise Levels

Low NoiseJune 6, 2008

Sept. 6, 2008 - Microseisms

Tropical Storm Hanna off coast of N and S Carolina

AS-1 Seismograph - Approximate Maximum Distance of Recording versus Magnitude

25

55

110

140

180

105

75

020406080

100120140160180

3.5 - 4.0

4.1 - 4.5

4.6 - 5.0

5.1 - 5.5

5.6 - 6.0

6.1 - 6.5

6.6 - 7.0

>7.0

Magnitude Range (Mw)

Ap

pro

xim

ate

Max

imu

m

Dis

tan

ce (

Deg

rees

)

AS-1 Seismograph – Approximate Distance of Recording versus Magnitude

Comparison of WLIN AS-1 seismogram with SFIN (about 10 km from WLIN) STS 2 seismogram for 2010 Haiti earthquake

WLIN AS-1 vertical component, low pass filtered twice with 10 s period cutoff

EarthScope SFIN vertical component, low pass filtered with 10 s period cutoff

Example of WLIN Station Earthquake List

WLIN AS-1 Seismograph 24-hour screen display for August 15-16, 2007

Example seismograms (local, regional, global, phases, recent, significant events)

AmaSeis 24-hour seismograph display – M8.1 Samoa Islands earthquake, September 29, 2009

AmaSeis seismogram display – M8.1 Samoa Islands earthquake, September 29, 2009

AmaSeis seismogram display, ~20 s period surface waves – M8.1 Samoa Islands earthquake, September 29, 2009

AmaSeis 24-hour seismograph display – M4.0 Mt. Carmel, Illinois earthquake, April 21, 2008

AmaSeis seismogram display – M4.0 Mt. Carmel, Illinois earthquake, April 21, 2008

AmaSeis seismogram display – M7.9 Kuril Islands earthquake, November 15, 2006

AmaSeis seismogram display – M7.9 Kuril Islands earthquake, November 15, 2006 – High pass filtered with 2 s period cutoff to see aftershocks

M6.3 Argentina deep focus (570 km) earthquake, Sept. 3, 2008

PpP P

PS

M6.3 Argentina deep focus (570 km) earthquake, Sept. 3, 2008

M6.3 Argentina deep focus (570 km) earthquake, Sept. 3,

2008 – AmaSeis Travel Time curve display

P pP

PP

S

AmaSeis seismogram display – M4.9 N. Utah earthquake, April 16, 2010

AmaSeis seismogram display – M6.0 Wells, Nevada earthquake, Feb. 21, 2008

M6.0 Wells Nevada earthquake, Feb. 21, 2008 – AmaSeis Travel Time curve

display

P S

AmaSeis seismogram display – M4.6 Evansville, Indiana earthquake, June 18, 2002

M4.6 Evansville, Indiana earthquake, June 18, 2002, AmaSeis Travel Time curve display

Actual epicentral distance = 2.59 degrees

Time (minutes)

AmaSeis seismogram display – M8.8 Chile earthquake, February 27, 2010

AmaSeis seismogram display – M7.2 N. Baja earthquake, April 4, 2010

Comparison of calculated earthquake to station distance and distance estimated from S – P times

N = 169; Standard Deviation = 1.89 degrees

MS Magnitudes: N = 270; Standard Deviation = 0.25 magnitude units.mb Magnitudes: N = 520; Standard Deviation = 0.26 magnitude units.mbLg Magnitudes: N = 34; Standard Deviation = 0.35 magnitude units.

Comparison of AS-1 and USGS Magnitudes

Comparison of AS-1 and USGS Mw Magnitudes

AS-1 mb, MS and mbLg magnitudes correlate well with M (Mw, moment magnitude) except for the largest earthquakes

Use of real and relevant scientific data, observing in real time

Students and teachers operate seismograph and record their own data

Real time monitoring – display in classroom

Analyze and interpret seismograms and obtain accurate information about earthquakes from the seismograms – phases, epicentral distance, earthquake magnitude

Connect to other discovery and learning activities (seismic waves, Earth structure, plate tectonics, seismicity, earthquake hazards)

WLIN data online – can be used with AmaSeis on any Windows computer (does not need to be connected to a seismometer) – Data files:http://web.ics.purdue.edu/~braile/edumod/as1lessons/as1lessons.htm (see #13), EQ List: http://web.ics.purdue.edu/~braile/edumod/as1lessons/InterpSeis/EqList.xls

Key aspects of earthquake recording with an educational seismograph and the Seismographs in Schools program

Thanks to John Lahrfor assistance, innovations

and insights for the educational seismology

program, his many other contributions to Earth

science education, and for being a great friend and

colleague!

Science for Planet Earth

braile@purdue.eduweb.ics.purdue.edu/~braile

April 2010

References and Resources

This PPT: http://web.ics.purdue.edu/~braile/ppt/ssa.ppt

IRIS Seismographs in Schools: http://www.iris.edu/hq/sis Using AmaSeis Tutorial:

http://web.ics.purdue.edu/~braile/edumod/as1lessons/UsingAmaSeis/UsingAmaSeis.htm

AS-1 Reosurces (See Number 13 for link to WLIN AS-1 continuous data and Excel spreadsheet earthquake list): http://web.ics.purdue.edu/~braile/edumod/as1lessons/as1lessons.htm

Interpreting Seismograms Tutorial: http://web.ics.purdue.edu/~braile/edumod/as1lessons/InterpSeis/InterpSeis.htm