Earthquake Science Timeline

An earthquake and accompanying tsunami destroys and submerges the city of Helice, Greece.

First seismoscope in Chang Hêng, China.

830,000 deaths are reported in Shaanxi, China earthquake.

Great Japanese Earthquake with a destructive tsunami and more than 5000 deaths.

Great Lisbon Earthquake and tsunami on November 1 almost completely destroys the city.

Five strong earthquakes on and after February 5 in Calibria, Italy. Scientific field investigation.

Observed faulting after earthquake in Cutch, India on June 16 (Allah Bund).

First edition of Principles of Geology written by Charles Lyell.

Robert Mallet published his first general paper on earthquakes.

Early seismograph made by Karl Kreil. Faulting is observed after an earthquake in New Zealand on January 24.

Strike-slip offset is observed after M7.9 Fort Tejon, California earthquake on January 9. After an earthquake on December 16 in the Kingdom of Naples, Robert Mallet, an Irish engineer, coins the term “seismology” during his field investigation of the earthquake.

Seismological observations begun at Manila with seismoscopes, seismographs installed 1881-1889.

Scarps and strike-slip offset observed after earthquake in Owens Valley, California on March 26.

A seismograph is developed in Japan by Alfre Ewing using a 7-meter long pendulum.

Seismological Society of Japan organized.

Explosion of Krakatoa volcano on August 27.

Rossi-Forel intensity scale is set up. Seismological service established in Manila.

Lord Rayleigh publishes a paper on the theory of "Rayleigh waves."

Voigt investigates the elasticity of crystals, tensors are named and defined. Rudolph publishes the first paper on seaquakes. Seismological stations are established in California at Berkeley and Lick Observatory.

Amuri, New Zealand earthquake occurs on September 1, and strike-slip at the surface offsets fences.

First seismogram of a teleseism is identified by Ernst von Rebeur-Paschwitz from a recording of seismic waves on pendulums in Potsdam and Wilhemshaven, Germany.

Mino-Owari earthquake occurs in Japan with large strike-slip and dip slip.

Japanese Imperial Earthquake Investigation Committee established. Sumatra earthquake on May 17, strike-slip shown by triangulation survey.

New seismographs developed by Vincentini in Padua, Italy and by Milne in England.

Seismology Committee of the British Association for the Advancement of Science is organized.

Great earthquake of Assam, India on June 12, investigation by Oldham.

Seismograph developed by Omori at Tokyo. Stations with Milne instruments initiated at Wellington, New Zealand and Batavia, Java.

Knott's equations for reflection and refraction coefficients of elastic waves. Great Alaskan earthquakes occur on September 3 and 10 with uplifts reaching 47 feet.

A global network of 40 seismic stations is operational, sponsored by the British Association for the Advancement of Science and equipped with instruments designed by mining engineer John Milne.

Inverted pendulum seismograph is developed by Wiechert. Geophysical Institute founded at Gottingen.

International Seismological Association is organized.

Seismological station initiated at Uppsala, Sweden.

E.M. Anderson develops a theory that relates the direction of stress in the crust to three basic fault types – normal, strike-slip, and reverse faults.

Galitzin electromagnetic seismograph developed in Russia. Vertical-component seismograph set up by Straubel and Eppenstein at Jena, Germany. R.D. Oldham identifies three basic types of seismic waves: P waves, S waves, and L waves. A major deep-focus earthquake occurs under Japan on January 21. A Great earthquake occurs in Columbia and Ecuador on January 31. The Great 1906 San Francisco earthquake occurs on April 18, with a great extent of strike-slip faulting. A re-triangulation survey leads to elastic-rebound theory of earthquakes (see 1910).

A seismograph is developed by Mainka at Strassburg.

The Great Siberian meteorite fall occurs on June 30.

Andrija Mohorovicič, a Serbian seismologist, identifies the boundary between the Earth’s crust and mantle layers by the different velocities of seismic waves through each layer after an earthquake near Zagreb, Croatia on October 8. It is called the "Moho". A seismological station is established at Riverview near Sydney, Australia.

Henry Fielding Reid proposes the elastic rebound hypothesis to explain how earthquakes release accumulated energy when the fault slips, driven by plate tectonics. New instruments are installed at Berkeley.

Seismological Society of America is founded, and it begins publishing the Bulletin. New instruments are installed at Lick Observatory Station. The Galitzin vertical-component seismograph is developed in Russia. Theory of Love waves is introduced.

The radius of the core is determined by Gutenberg at Gottingen. Station established at La Paz, Bolivia.

Beno Gutenberg obtains the depth of the boundary between the Earth’s mantle and core.

Milne-Shaw seismograph is developed by J.J. Shaw in England.

First year covered by International Seismological Summary.

Zoeppritz equations for coefficients of reflection and refraction of elastic waves is published (posthumously).

Carnegie Institution of Washington, Advisory Committee in Seismology appointed. Explosion at Oppau, Germany on September 21.

Changes in the variation of latitude and in other geophysical elements.

The first global earthquake bulletins are made from internationally-shared seismic data. Wood-Anderson torsion seismometers began regular recording in Pasadena, California.

In response to the M7.9 1923 Kanto, earthquake, Japan establishes building codes for construction so that buildings can withstand shaking from large earthquakes. Nikiforov torsion seismographs in the service in the USSR.

Jesuit Seismological Association is organized with headquarters at St. Louis. Seismological work transferred from U.S. Weather Bureau to Coast and Geodetic Survey.

Geophysical Magazine (Tokyo) begins publication. Earthquake department of Pacific Board of Fire Underwriters established.

Seismological Laboratory at Pasadena occupied. The Tango earthquake in Japan occurs on March 7, is thoroughly investigated and found to have two fault traces.

K. Wadati publishes a paper on shallow and deep earthquakes.

New electromagnetic seismograph developed by Wenner. A New Zealand earthquake on June 17 sparks expansion of New Zealand seismology.

Variable-reluctance seismometer developed by Benioff in Pasadena, California. Permanent seismic stations are established around the world, and strong-motion seismometers (best at measuring seismic waves that damage buildings) are installed in some urban areas.

Benioff strain seismometer developed. U.S. Coast and Geodetic Survey initiates a program of strong-motion recording in California.

Great Sanriku earthquake and tsunami occurs on March 3. Permanent seismic stations are established around the world, and strong-motion seismometers (best at measuring seismic waves that damage buildings) are installed in some urban areas.

P'P' (P-prime P-prime) and related waves discovered at Pasadena.

Charles Richter develops the Richter Scale to measure earthquake size.

Inge Lehmann, a Danish seismologist, discovers the Earth’s inner core.

Istituto Nazionale di Geofisica established with headquarters at Rome.

On December 27 a destructive earthquake occurs in Turkey, the first of a series of extended and connected faulting.

T wave described and named by Linehan in Weston, Massachusetts. Harold Jeffreys and Keith Bullen create a model of the Earth’s interior based on seismic waves recorded around the world. The seismic travel-time tables are then used to locate earthquakes for the next 50 years.

Seismicity of the Earth is published by Richter and Gutenberg, a classic book that documents that earthquakes are concentrated in narrow zones throughout the globe. These narrow zones are later recognized as the plate boundaries.

Annals de Geophysics begins publication.

On April 1, an M7.1 Aleutian Island earthquake generates a deadly tsunami that causes destruction on Hawaii. A seismic sea warning service is organized as a consequence. On July 24, an atomic bomb test at Bikini produces P waves that are recorded at distant stations.

Hegelian demolition on April 18.

The U.S. Coast and Geodetic Survey distributes the first earthquake probability map for the U.S. with 4 different hazard zones. C. A. Whitten, of the U.S. Coast and Geodetic Survey, publishes a paper on continuing horizontal displacements in California.

Annali di Geofisicia begins publication. A large quarry blast in Corona, California is recorded on August 6.

Japan deploys a warning system to stop trains when an earthquake is detected. On August 15, a Great earthquake occurs that affects Tibet and Assam.

Strain-release curves are developed by Benioff in Pasadena, California.

Lg waves are discovered by Ewing and Press at Columbia University, New York.

Pa and Sa waves are discovered by Caloi at Rome, and independently by Ewing and Press.

An earthquake occurs on March 29 at a very deep 640 kilometers under Spain.

On December 16, a major earthquake occurs in Nevada with large and extensive faulting.

Richter and Gutenberg develop formulas for calculating seismic energy, which were also used to determine the size of nuclear explosions.

The World Wide Standardized Seismographic Network (WWSSN) is started. It has high quality instruments able to record smaller earthquakes than before and able to get more accurate locations. The U.S. Uniform Building Code is modified to account for different building types and the level of seismic hazard in the region.

The M9.2 Alaskan earthquake is the second largest in the 20th century, causing a tsunami 9 meters high and causing the planet to “ring like a bell”, enabling measurements of the Earth’s free oscillations, and providing definitive evidence of the subduction of the Pacific Plate beneath the North American plate beneath the continental margin of southern Alaska. The ground shaking in the M7.5 earthquake near Niigata, Japan causes liquefaction of the loose, water-saturated sediments, resulting in the tilting of some large apartment buildings.

Plate tectonics becomes a unified theory that brings together all the earthquake science up to that point and provides a basis upon which to build moving forward. New information shows that the amount of crust being subducted is balanced by the amount being produced at the mid-ocean ridges. A computer-generated map of earthquake locations around the world is used to delineate the major plate boundaries.

W.F. Brace and J.D. Byerlee demonstrate that an engineering phenomenon known as stick-slip also applies to geological materials, providing explanation for Reid’s elastic rebound theory. The National Earthquake Information Center (NEIC) is established in the U.S.

The M6.6 San Fernando earthquake near Los Angeles is recorded by 200+ strong-motion seismometers, showing for the first time a detailed picture of how ground shaking varies with time during an earthquake, and also varies greatly from place to place.

California passes the Alquist-Priolo Special Studies Act in 1972 that restricts the construction of new buildings for human occupancy across active fault zones. Land remote sensing imagery (Landsat) becomes available, allowing researchers to map faults in inaccessible areas.

An M7.3 earthquake near Haicheng, China is predicted about 24 hours in advance based on local increased seismic activity and changes in local water wells, and results in an evacuation of thousands unsafe buildings. T he earthquake destroys 90% of the city but with very few casualties, so the prediction is declared a success. A year later an M?.? earthquake happens near Tangshan, China with no prediction, killing more than 240,000 people, one of the highest death tolls from an earthquake.

Congress establishes the National Earthquake Hazard Reduction Program (NEHRP) to reduce the risks to life and property from future earthquakes in the U.S. and its territories. The Program is still in existence today.

Paleoseismology (the study of ancient earthquakes in the geologic record) is used to look at past earthquakes on the San Andreas Fault.

The Global Seismographic Network (GSN) of broadband seismic stations is initiated with the founding of IRIS (Incorporated Research Institutes for Seismology). This network replaces the older WWSSN stations.

Japan installs continuously-recording GPS (Global Positioning System) stations for measuring tectonic deformation. With GPS satellites, these can be used for very precise locations of any point on Earth’s surface.

M6.9 Loma Prieta, California earthquake on October 17 causes $10.7 billion in losses.

InSAR (interferomatic synthetic aperture radar) technology is used to image earthquake faulting with more detail than ever possible before. InSAR measures deformation by comparing reflected radar waves recorded on successive passes of a satellite from nearly identical positions.

M6.7 Northridge, California earthquake on January 17 causes $64.0 billion in losses.

An M6.9 directly under Kobe, Japan kills more than 5500 people and destroys more than 100,000 buildings, causing roughly $200 billion in direct economic losses.

The USGS publishes a new series of national seismic hazard maps with contours showing 3 hazard levels for 4 different types of shaking (different frequencies).

Computer simulations and denser seismic networks provide the ability to simulate pictures of how the rupture occurs on the faults during the earthquakes. The first global seismic hazard map is produced.

The M9.1 Great Sumatra earthquake and tsunami occurs, Congress increases earthquake funding.

The National Earthquake Information Center (NEIC) becomes a 24x7 operation.

The Advanced National Seismic System (ANSS) network completes installment of 100th station.

QuakeML is released as the international standard for earthquake metadata exchange.