What is the primary mission of the International Seismological Centre (ISC)?

The International Seismological Centre (ISC) is primarily charged with the final collection, definitive analysis, and publication of global seismicity data. This means it gathers comprehensive information about earthquakes from around the world, processes it thoroughly, and makes it available to the scientific community and the public.

When was the International Seismological Centre established, and what prompted its formation?

The International Seismological Centre (ISC) was formed in 1964 as an international organization, independent of national governments. Its establishment was prompted by the need to continue the work of the International Seismological Summary (ISS) and to handle the increased flow of seismic data resulting from the creation of the World-Wide Standard Seismograph Network (WWSSN) in the same year.

How is the ISC's earthquake catalog recognized within the global seismological community?

The ISC's earthquake catalog is recognized as 'the most complete and authoritative final depository of global earthquake parameter data.' This highlights its status as a definitive and comprehensive source for worldwide earthquake information.

What is the main scientific objective that guides the ISC's operations?

The main scientific objective of the International Seismological Centre is the definitive compilation of earthquake information and the seismic readings upon which these events are based. This involves meticulously gathering and processing all relevant data to create a precise and complete record of seismic activity.

Besides instrumental readings, what other crucial information does the ISC collect regarding earthquakes?

Beyond instrumental seismic readings, the ISC also collects reports detailing the effects of earthquakes. This collection is an important part of its operations, contributing to a more holistic understanding of seismic events and their impact.

How does the ISC ensure accuracy when determining earthquake locations and times globally?

The ISC ensures accuracy by recomputing the location and occurrence time of earthquakes worldwide, making use of all available information. This comprehensive approach helps to refine and standardize earthquake parameters across its database.

What significant technological shift occurred in the ISC's data manipulation process after 1957?

After 1957, a significant technological shift occurred in the ISC's data manipulation process, with the large volume of data being mainly handled by computer. Prior to this, locations for the International Seismological Summary (ISS) were determined manually with the aid of a large globe.

What kind of database and computing resources does the ISC currently utilize for its operations?

The ISC currently utilizes a network of workstations that access a relational database containing nearly 50 gigabytes of online data. A relational database is a structured collection of information that organizes data points with defined relationships for efficient storage and retrieval.

Describe the typical timeline and batching process for the ISC's earthquake data analysis.

The ISC undertakes the analysis of earthquake data in monthly batches, beginning after at least 18 months have passed since the events occurred. This extended waiting period allows for the information used to be as complete as possible, ensuring a thorough and definitive analysis.

What is the role of human seismologists in the ISC's data analysis, despite extensive computerization?

Despite extensive computerization, human seismologists play a critical role in the final editing of large earthquake events detected by multiple independent networks. They scrutinize the computer output for unlikely events and potential misassociations of readings, ensuring the quality and accuracy of the data.

How does the ISC's computer program initially process and associate station readings with seismic events?

During analysis, the ISC's computer program first groups origin estimates received from various agencies. It then proceeds to associate individual station readings with the most probable seismic event, forming the initial basis for earthquake identification.

What is the typical monthly volume of station readings analyzed and events identified by the ISC?

In a typical month, the ISC analyzes more than 200,000 station readings, which leads to the identification of an average of 10,000 events. Of these identified events, approximately 4,000 usually require manual review by seismologists.

How does the ISC ensure its list of earthquake events is fully comprehensive, surpassing other services?

To ensure a fully comprehensive list, the ISC rectifies any misassociations and discrepancies found in the data. Furthermore, it actively searches unassociated readings for new events and adds previously unreported earthquakes to its database, resulting in a total number of listed events that is several times greater than those provided by other worldwide location services.

What is the ISC Bulletin, and why is its Reviewed Bulletin considered particularly important?

The ISC Bulletin is the primary collection of ISC data, organized by seismic events, and is available online, with a printed summary offered for a fee. Its Reviewed Bulletin is considered particularly important because, after approximately two years, all data for an event is reviewed, and its hypocenters and magnitudes are recalculated, making it 'the definitive record of the Earth's seismicity.'

What is the relationship between the original EHB Bulletin and the current ISC-EHB Bulletin?

The original EHB Bulletin contained events from 1960 to 2008, with hypocenters recalculated using a specific algorithm by Engdahl, van der Hilst & Buland (1998). The ISC-EHB Bulletin is an updated version that has replaced the original, extending the catalog to include events up to 2013.

For what specific purpose was the ISC-GEM Global Instrumental Earthquake Catalogue created?

The ISC-GEM Global Instrumental Earthquake Catalogue (1900-2013) was created at the request of the Global Earthquake Model (GEM Foundation) specifically to catalog earthquakes of magnitude 5.5 or greater. These events are deemed suitable for modeling and assessing seismic hazard and risk, providing a standardized dataset for such analyses.

How are epicentral locations and hypocentral depths determined for the ISC-GEM Catalogue?

For the ISC-GEM Catalogue, epicentral locations and hypocentral depths are meticulously recalculated from original travel time data. This recalculation is performed using a consistent velocity model to ensure accuracy and uniformity across the catalogue. An epicenter is the point on the Earth's surface directly above an earthquake's origin, while the hypocenter is the actual point within the Earth where the earthquake originates.

Which magnitude scale is predominantly used in the ISC-GEM Catalogue, and how are its values derived?

The moment magnitude scale (Mw) is predominantly used in the ISC-GEM Catalogue. The values are derived either from reliable published seismic moment values or from recalculated surface wave or body wave magnitudes, which are then converted to Mw using established empirical relationships.

What types of events are included in the IASPEI Ground Truth (GT) reference events database?

The IASPEI Ground Truth (GT) reference events database includes 9280 earthquakes and explosions. These events are characterized by their hypocenters being located with high precision, typically within 10 kilometers or less, often confirmed through on-site studies referred to as 'ground truth.'

What is the primary significance of the IASPEI Ground Truth (GT) reference events database?

The primary significance of the IASPEI Ground Truth (GT) reference events database is that these events have been selected to improve the understanding of the Earth's internal structure. They also serve as crucial references for more accurately calibrating seismic networks, thereby enhancing the precision of global earthquake monitoring.

What is the purpose and benefit of the ISC's Event Bibliography?

The ISC's Event Bibliography serves to catalog scientific papers, primarily in English, that specifically discuss over 14,000 seismic events. Its benefit lies in avoiding common search problems encountered with general search services, such as variant place names, spellings, or trivial mentions, making it a valuable resource for researchers.

Who is the current Director of the International Seismological Centre, as of the latest information provided?

D.A. Storchak has been the Director of the International Seismological Centre from 2008 to the present, according to the provided information.

Who was the first individual to serve as Director of the International Seismological Centre after its formation?

P.L. Willmore was the first individual to serve as Director of the International Seismological Centre, holding the position from 1964 to 1970.

Who was responsible for publishing the 'Shide Circular Reports on Earthquakes' between 1900 and 1912?

J. Milne was responsible for publishing the 'Shide Circular Reports on Earthquakes' during the period from 1900 to 1912.

Which individual held the directorship of the International Seismological Summary (ISS) for the longest continuous period listed?

H.H. Turner held the directorship of the International Seismological Summary (ISS) for the longest continuous period listed, serving from 1918 to 1931.

What was the staff count of the International Seismological Centre in 2018?

In 2018, the International Seismological Centre had a staff count of 20 individuals.

What is the official web address for the International Seismological Centre?

The official web address for the International Seismological Centre is http://www.isc.ac.uk/.

What was the name of the publication that H.H. Turner published from 1912 to 1917?

H.H. Turner was the publisher of 'Reports on Large Earthquakes' from 1912 to 1917.

Who served as the Director of the International Seismological Summary (ISS) immediately prior to P.L. Willmore's tenure?

R. Stoneley served as the Director of the International Seismological Summary (ISS) from 1952 to 1960, immediately preceding P.L. Willmore's tenure in that role.

What is the significance of the logo displayed for the International Seismological Centre?

The logo displayed for the International Seismological Centre serves as its official identifier, visually representing the organization.

Why does the U.S. Geological Survey (USGS) refer to the ISC's final bulletin as 'preliminary'?

The U.S. Geological Survey (USGS) refers to the ISC's final bulletin publication as 'preliminary' because of the ISC's authoritative role as the definitive record of global earthquake parameter data. This implies that the USGS's own initial reports are considered preliminary until the ISC's comprehensive and final analysis is available.

What is the organizational structure of the International Seismological Centre in terms of governance and funding?

The International Seismological Centre is structured as a non-governmental, nonprofit organization. This means it operates independently of direct government control and focuses its resources on its scientific mission rather than on generating financial profit.

Which director served the longest continuous term for the International Seismological Centre itself?

A.A. Hughes served the longest continuous term as Director of the International Seismological Centre, from 1977 to 1997.

What is the purpose of converting various magnitude scales to Moment Magnitude (Mw) in the ISC-GEM Catalogue?

The purpose of converting various magnitude scales, such as surface wave or body wave magnitudes, to Moment Magnitude (Mw) in the ISC-GEM Catalogue is to ensure consistency and provide a uniform measure of earthquake size. This standardization, achieved through empirical relationships, is crucial for accurate seismic hazard and risk modeling.

How does the ISC's data collection and analysis contribute to global seismicity understanding?

The ISC's comprehensive data collection and definitive analysis of global seismicity contribute to a deeper understanding of earthquake phenomena worldwide. By compiling and re-analyzing all available seismic data, it provides an authoritative record that informs scientific research, hazard assessment, and seismic network calibration.

What was the role of Sir Harold Jeffreys in the history of seismological data compilation?

Sir Harold Jeffreys served as the Director of the International Seismological Summary (ISS) from 1939 to 1952, playing a significant role in the compilation and analysis of seismological data during that period.

What is the minimum magnitude threshold for earthquakes included in the ISC-GEM Global Instrumental Earthquake Catalogue?

The minimum magnitude threshold for earthquakes included in the ISC-GEM Global Instrumental Earthquake Catalogue is magnitude 5.5 or greater.

How does the ISC's approach to identifying events, including manual review, ensure data quality?

The ISC's approach to identifying events, which includes analyzing over 200,000 station readings monthly and subjecting approximately 4,000 identified events to manual review by seismologists, ensures data quality. This combination of automated processing and expert human scrutiny helps to rectify misassociations and identify previously unreported earthquakes, leading to a highly accurate and comprehensive catalog.

What is the primary benefit of the ISC being an international organization independent of national governments?

The primary benefit of the ISC being an international organization independent of national governments is that it can provide an unbiased and globally consistent collection, analysis, and publication of seismicity data. This independence fosters trust and ensures a neutral, scientific approach to earthquake monitoring.

International Seismological Centre Wiki: Seismic Sentinels: The International Seismological Centre's Global Mission

Dive in with Flashcard Learning!

When you are ready...
🎮 Play the Wiki2Web Clarity Challenge Game🎮

Overview ISC?

Global Seismicity Authority

The International Seismological Centre (ISC) stands as a pivotal non-governmental, non-profit organization dedicated to the definitive collection, rigorous analysis, and comprehensive publication of global seismicity data.^[1] Established in 1964, its inception marked a crucial step in advancing global seismic monitoring, particularly in response to the increased data flow from the newly formed World-Wide Standard Seismograph Network (WWSSN).^[2]

Core Mission: Definitive Data

The ISC's primary objective is to meticulously collect and re-analyze all available seismic data worldwide to produce the most authoritative and complete record of earthquake parameters.^[3] Its catalog is globally recognized as "the most complete and authoritative final depository of global earthquake parameter data," serving as a fundamental resource for seismologists and researchers alike.^[4]

Institutional Evolution

The ISC inherited and expanded upon the vital work of its predecessor, the International Seismological Summary (ISS). This continuity ensured a seamless transition in the global effort to systematically document and understand seismic events, adapting to technological advancements and the growing complexity of seismic data acquisition.^[2]

Purpose

Comprehensive Earthquake Information

The main scientific goal of the ISC is the definitive compilation of earthquake information, including the precise readings upon which these determinations are based. This encompasses not only instrumental data but also reports of earthquake effects, which are crucial for a holistic understanding of seismic events.

Recalculating Global Events

A core function involves the recomputation of the location and occurrence time of earthquakes across the globe. This process leverages all available information, ensuring the highest possible accuracy for each seismic event recorded. This meticulous re-analysis is what distinguishes the ISC's data as definitive.

Data Management Evolution

Since 1957, the sheer volume of seismic data has necessitated the use of computers for manipulation and analysis, a significant leap from the manual methods (like using a large globe) employed by the ISS. Today, the ISC operates with a sophisticated network of workstations accessing a relational database containing nearly 50 gigabytes of online data, enabling efficient processing of vast datasets.

Method

Batch Processing & Delay

The analysis of earthquake data at the ISC is undertaken in monthly batches. A deliberate delay of at least 18 months is implemented before final processing begins. This critical waiting period ensures that the information used is as complete as possible, allowing for the inclusion of late-arriving data from various seismic stations worldwide, thereby enhancing the accuracy and comprehensiveness of the final catalog.

Automated Analysis & Human Expertise

While extensive computer programs are indispensable for handling the massive data volume, the final editing of significant events—those detectable by multiple independent networks—is always performed by experienced seismologists. These experts scrutinize the automated output for any unlikely events or potential misassociations of readings, ensuring the integrity and reliability of the data.

Data Volume & Review

In a typical month, the ISC processes over 200,000 station readings. This rigorous analysis leads to the identification of approximately 10,000 events, of which about 4,000 require manual review by seismologists. Discrepancies and misassociations are rectified, and unassociated readings are carefully examined to identify new events or previously unreported earthquakes, which are then added to the database. This comprehensive approach results in a total number of listed events several times greater than those provided by any other global location service.

Products

ISC Bulletin

The On-line Bulletin serves as the primary repository of ISC data, meticulously organized by individual seismic events. After approximately two years, all collected data for an event undergoes a thorough review, leading to the recalculation of hypocenters and magnitudes. This Reviewed Bulletin is widely regarded as the definitive record of the Earth's seismicity.^[5] Most other ISC data products are derived subsets of this comprehensive bulletin.

ISC-EHB Bulletin

The original EHB Bulletin, covering events from 1960 to 2008, featured hypocenters recalculated using the algorithm developed by Engdahl, van der Hilst & Buland (1998). This has since been superseded by the ISC-EHB Bulletin, which extends this catalog to 2013, incorporating advancements in location algorithms to provide refined earthquake parameters.

ISC-GEM Catalogue

Prepared at the behest of the Global Earthquake Model (GEM) Foundation, the ISC-GEM Global Instrumental Earthquake Catalogue (1900-2013) is a specialized catalog focusing on earthquakes of magnitude 5.5 or greater. It is specifically designed for modeling and assessing seismic hazard and risk. Epicentral locations and hypocentral depths are recalculated from original travel time data using a consistent velocity model, and magnitudes are expressed as moment magnitude scale (M_w), derived from reliable published values or converted from surface wave or body wave magnitudes.^[6]

IASPEI GT Events

The IASPEI Ground Truth (GT) reference events database comprises 9280 earthquakes and explosions. A distinguishing feature of these events is that their hypocenters have been located with exceptional precision, typically within 10 kilometers or less, often corroborated by on-site studies. These events are strategically selected to enhance our understanding of Earth's internal structure and to provide robust reference points for the accurate calibration of seismic networks globally.

Event Bibliography

The Event Bibliography is a valuable resource that catalogs scientific papers, predominantly in English, which specifically discuss over 14,000 seismic events. This curated listing circumvents common challenges encountered with general search services, such as variations in place names, spellings, or trivial mentions, providing a focused and reliable guide to event-specific research.

History

Evolution of Global Seismology

The International Seismological Centre's lineage traces back to early 20th-century efforts to systematically record and analyze global earthquake data. This historical progression highlights the continuous commitment to advancing seismological understanding and data dissemination.

1900–1912: Publication of the "Shide Circular Reports on Earthquakes" under J. Milne.
1912–1917: Publication of "Reports on Large Earthquakes" under H.H. Turner.
1918–1963: Era of the International Seismological Summary (ISS), with various directors overseeing its operations.
1964: Formation of the International Seismological Centre (ISC), building upon the foundation laid by the ISS and adapting to the demands of new global seismic networks like WWSSN.

Leadership Through the Decades

The ISC and its predecessors have been guided by a series of distinguished directors, each contributing to the organization's enduring legacy in global seismology.

Publishers of "Shide Circular Reports on Earthquakes"

1900–1912: J. Milne

Publishers of "Reports on Large Earthquakes"

1912–1917: H.H. Turner

Directors of the International Seismological Summary

1918–1931: H.H. Turner
1931–1939: H. Plaskett
1939–1952: Sir Harold Jeffreys
1952–1960: R. Stoneley
1960–1963: P.L. Willmore

Directors of the International Seismological Centre

1964–1970: P.L. Willmore
1970–1977: E.P. Arnold
1977–1997: A.A. Hughes
1998–2003: R.J. Willeman
2004–2007: A. Shapira
2008–present: D.A. Storchak

Teacher's Corner

Edit and Print this course in the Wiki2Web Teacher Studio

Edit and Print Materials from this study in the wiki2web studio

Click here to open the "International Seismological Centre" Wiki2Web Studio curriculum kit

Use the free Wiki2web Studio to generate printable flashcards, worksheets, exams, and export your materials as a web page or an interactive game.

True or False?

Test Your Knowledge!

Gamer's Corner

Are you ready for the Wiki2Web Clarity Challenge?

Learn about international_seismological_centre while playing the wiki2web Clarity Challenge game.

Unlock the mystery image and prove your knowledge by earning trophies. This simple game is addictively fun and is a great way to learn!

Play now

Explore More Topics

Discover other topics to study!

indiana university press

References

Di Giacomo et al. 2014, p. 354; Johnston & Halchuk 1993, p. 134.

Adams 2010; Musson 2013, pp. 831â833.

A full list of references for this article are available at the International Seismological Centre Wikipedia page

Feedback & Support

To report an issue with this page, or to find out ways to support the mission, please click here.

Disclaimer

Important Notice

This page was generated by an Artificial Intelligence and is intended for informational and educational purposes only. The content is based on a snapshot of publicly available data from Wikipedia and may not be entirely accurate, complete, or up-to-date.

This is not official data or professional advice. The information provided on this website is not a substitute for consulting the official International Seismological Centre (ISC) publications, databases, or seeking expert advice from qualified seismologists or geological professionals. Always refer to the primary sources and consult with specialists for any critical research, hazard assessment, or professional applications of seismological data. Never disregard official data or professional guidance because of information presented here.

The creators of this page are not responsible for any errors or omissions, or for any actions taken based on the information provided herein.

Seismic Sentinels

💡 Dive in with Flashcard Learning! 💡

Overview ISC? ℹ️

🌐 Global Seismicity Authority

🎯 Core Mission: Definitive Data

🏛️ Institutional Evolution

Purpose 🔍

📈 Comprehensive Earthquake Information

📍 Recalculating Global Events

💻 Data Management Evolution

Method ⚙️

🗓️ Batch Processing & Delay

🧠 Automated Analysis & Human Expertise

📊 Data Volume & Review

Products 📦

📜 ISC Bulletin

🔄 ISC-EHB Bulletin

💎 ISC-GEM Catalogue

📍 IASPEI GT Events

📚 Event Bibliography

History 🕰️

📜 Evolution of Global Seismology

👨‍🏫 Leadership Through the Decades

Publishers of "Shide Circular Reports on Earthquakes"

Publishers of "Reports on Large Earthquakes"

Directors of the International Seismological Summary

Directors of the International Seismological Centre

Teacher's Corner 🧑‍🏫

Edit and Print this course in the Wiki2Web Teacher Studio

True or False? 🤔

❓ Test Your Knowledge! ❓

Gamer's Corner 🎮

Are you ready for the Wiki2Web Clarity Challenge?

Explore More Topics

📜 Discover other topics to study!

References

📜 References

Feedback & Support 👍

To report an issue with this page, or to find out ways to support the mission, please click here.

Disclaimer ⚠️

📜 Important Notice

Dive in with Flashcard Learning!

Overview ISC?

Global Seismicity Authority

Core Mission: Definitive Data

Institutional Evolution

Purpose

Comprehensive Earthquake Information

Recalculating Global Events

Data Management Evolution

Method

Batch Processing & Delay

Automated Analysis & Human Expertise

Data Volume & Review

Products

ISC Bulletin

ISC-EHB Bulletin

ISC-GEM Catalogue

IASPEI GT Events

Event Bibliography

History

Evolution of Global Seismology

Leadership Through the Decades

Teacher's Corner

True or False?

Test Your Knowledge!

Gamer's Corner

Discover other topics to study!

References

Feedback & Support

Disclaimer

Important Notice