Publications Prospective and retrospective evaluation of five-year earthquake forecast models for California Share Facebook LinkedIn Download 2017 | Peer-reviewed Using a score to generalize the model performance into one numeric value has been one of the most popular approaches to empirically evaluate ground‐motion models (GMMs). This approach has an advantage of simplifying model comparison. We study the effects of data correlation and score variability on the evaluation of GMMs. Most modern GMMs are hierarchical, in which ground motions from the same earthquake are modeled as correlated. We demonstrate, with examples, that incorrect results could occur if such hierarchical GMMs are evaluated by a score that does not duly address the data correlation. We propose to use the multivariate logarithmic score, a natural extension of the widely used univariate logarithmic score (referred to as LLH in the seismological literature), to correctly score hierarchical GMMs. The score variability affects the interpretation of model ranking. We demonstrate that the cluster bootstrap is a better bootstrap strategy, compared with other strategies proposed in the literature, to study the score variability. The bootstrap allows computing two useful quantities: the distinctness index that indicates if two models are truly different given the score variability and the frequency weight, a data‐driven weighting scheme that represents the frequentist’s interpretation of the weight of a logic‐tree branch. The frequency weight has a direct link to the current practice of using multiple GMMs in a probabilistic seismic hazard assessment.

License Request Form You have chosen to get more information about: Türkiye Hazard Hazard Please check the link below to see if this product already meets your your requirements before submitting your request for a license. Thank you. DOWNLOAD THE OPEN VERSION Summary of steps to obtain a license for the requested product. Fill in the application form below. Click Submit. Please check your email Inbox or Spam folder for the summary of your request. You will then be contacted by the GEM Product Manager with either a request for more information, or a request to sign the license. If you do not hear from us within 2 weeks, please send an email to product@globalquakemodel.org . REQUEST DETAILS A. Requesting party information First Name Last Name Role/Job Email Business type Business type Other business Sector Sector Other sector B. License agreement signatory information The signatory must be someone who is authorised to sign license agreements on your behalf such as your immediate supervisor, manager or legal officer. If you’re a PhD student, the signatory must be your adviser or a university officer in charge of license agreements or similar legal documents. Full Name of Signatory Position Company Email of Signatory Organisation name Complete Address C. Purpose of request GEM is able to offer products for free because of the support of our project partners, national collaborators and institutional sponsors. All of GEM’s products are freely available for public good, non-commercial use, but with different license restrictions. In most cases we release products under an open license (e.g., CC BY-SA or CC BY-NC-SA), which permits (re)distribution. In this case, we are granting access under a more restricted license that forbids distribution or disclosure and requires signing by GEM and the licensee in order to better assure accountability for the confidentiality of the information. In order for GEM to properly assess your request, please answer the following questions below. 1. Explain briefly how will the GEM product be used e.g. project, research including the expected results and the foreseen public benefit. Minimum 60 words. 2. Will you be able to share the results of your work with GEM? YES NO 3. Will you be able to provide feedback to GEM on the quality and usefulness of this product via a survey? YES NO D. Privacy Policy By submitting this form, you consent to the processing of your personal data in accordance with our Privacy Policy and the EU General Data Protection Regulation (GDPR). We are committed to safeguarding your information and ensuring it is only used for the purpose outlined in this form. You have the right to access, rectify, or delete your data at any time. For more information, please refer to our Privacy Policy. I agree Words: 0 Email us at product@globalquakemodel.org if you're experiencing problems submitting your application. Thank you. Submit Thanks for submitting! You will be contacted as soon as possible Incomplete data. Please fill in all required fields. Thank you.

News Media update: New global earthquake hazard, risk, liquefaction and carbon resources now available By: Jun 30, 2026 Jun 30, 2026 Share Facebook LinkedIn The Global Earthquake Model (GEM) Foundation has released four new global resources on earthquake hazard, risk, infrastructure exposure and the carbon consequences of earthquake damage. Presented at GEM Conference 2026 in Zagreb on 23 June, the resources combine global, regional and national scientific models to help researchers, public authorities, infrastructure planners, insurers and other users understand where earthquake impacts may be greatest - and how those impacts may change in the future. Global Seismic Hazard Map GEM’s updated Global Seismic Hazard Map is GEM's first probabilistic seismic hazard map to cover the entire globe, including the oceans. It brings together 31 inland seismic hazard models, three ocean models and two polar models. Around 200 million people live in areas where there is a 10% chance in 50 years of earthquake shaking strong enough to accelerate the ground sideways at more than half the force of gravity. This is a level of shaking that can cause severe damage to vulnerable buildings. Global Seismic Risk Map The updated Global Seismic Risk Model represents 1.7 billion buildings , home to around 8.2 billion people , and assesses potential earthquake impacts including economic losses, buildings destroyed, fatalities, homelessness and embodied-carbon loss. More than three in five people worldwide live in buildings with no seismic provisions. For the first time, the model also examines how earthquake risk could evolve by 2045 and 2065 under different development scenarios. These are not forecasts of future earthquakes; they show how changing populations, building stock and construction practices could affect future earthquake risk. Global Liquefaction Map GEM has assessed 17.5 million km of roads worldwide. Nearly one in every eight kilometres of the mapped road network is exposed to high earthquake shaking, while around 135,000 km are located in areas with severe liquefaction hazard. Liquefaction occurs when water-saturated ground loses strength during an earthquake. It can damage roads, bridges and underground services, disrupt evacuation and emergency routes, and delay recovery. In Japan, more than one quarter of the road network is located in areas with severe liquefaction hazard; in the Philippines, the figure is 16%. Global Seismic Embodied-Carbon Risk Map This new resource estimates the carbon footprint of earthquake damage and reconstruction. It does not refer to the energy buildings use in daily operation. Instead, it estimates the emissions associated with producing, transporting and installing materials needed to repair or rebuild damaged buildings. GEM estimates that earthquakes result in an average annual reconstruction footprint of around 17 million metric tonnes of CO₂e worldwide - roughly comparable to 85,000 transatlantic passenger flights . The findings show that earthquake resilience and climate objectives are closely linked: reducing building damage can also avoid substantial future reconstruction emissions. FOR JOURNALISTS Media resources: Product maps, posters, technical documentation and access details are available through the hyperlinked maps above. High-resolution map images and additional background can be arranged on request. Media contact: communication@globalquakemodel.org No images found. GALLERY GEM_Global_Seismic_Risk_Map_2026-1_losses.png GEM_Global_Seismic_Hazard_Map_2026-1.png GEM_Global_Exposure_Map_2026-1_occupants.png GEM_Global_Seismic_Risk_Map_2026-1_losses.png 1/10 VIDEO RELATED CONTENTS

News SERA European Building Exposure Workshop: From European Hazard to Risk By: Apr 26, 2018 Share Facebook LinkedIn The EUCENTRE organized and hosted the European Building Exposure Workshop from 1st – 2nd March in Pavia as part of the Horizon 2020-funded SERA project, with the aim to review initial exposure models and their underlying assumptions for a number of countries in Europe. The workshop brought together experts with knowledge on the residential, commercial and industrial buildings in Europe, or who had developed country-wide building inventories for public or private seismic risk applications. The 2-day workshop facilitated by Helen Crowley - EUCENTRE-SERA, produced the following: - revised classification scheme that could be used for building types in Europe, insights into building practices and design codes from the participants’ respective countries, - mapping schemes for the distribution of building types across each country (residential, commercial and industrial), - identified assumptions on replacement costs and - areas of buildings and list of available sources of data on buildings from the participants’ countries. About 30 professional from various parts of Europe including GEM’s Vitor Silva - Seismic Risk Coordinator and Venetia Despotaki - Physical Risk Engineer participated in the workshop. The 2-day event covered a wide range of topics including filling out a comprehensive online questionnaire on building classification; and presentations on: - GEM’s Risk modelling framework by Vitor Silva;- Development of residential and non-residential exposure models in SERA and- Explanation of SERA preliminary mapping schemes by Venetia Despotaki. Other participants presented insights into building stock in Bulgaria, Croatia, Slovenia, Iceland, and France. The SERA project is collaborating closely with the GEM Foundation (Global Earthquake Model) to: develop a European Risk Modelling framework that brings together the strengths of previous projects such as SHARE, NERA and fills in the research gaps; integrate knowledge and data from other SERA working packages; and build on the risk assessment framework and software developed by GEM. No images found. GALLERY 1/0 VIDEO RELATED CONTENTS

News Scientific Collaboration a vital element for productivity By: May 21, 2020 Share Facebook LinkedIn In this story, GEM interviewed Phil Cummins of Geoscience Australia to get to know how he got started with earthquake hazard and risk modelling, his insights, perspectives on the impact of GEM on earthquake hazard model development, the importance of supporting GEM initiatives and the importance of its work especially in places in the world where earthquake risk is very much underappreciated. Here’s an excerpt from his interview entitled: Scientific Collaboration a vital element for productivity. “GEM impacted the way we do work at Geoscience Australia because our partnership with GEM allowed us to focus more on the quality of our data and our data analysis rather than the software development. And this really resulted in a dramatic improvement in the Australian earthquake hazard model.” - Phil Cummins The full story is available at https://www.globalquakemodel.org/gemstories/scientific-collaboration-a-vital-element-for-productivity . If you're a GEM partner and have a story to share that leverages GEM products and expert advice; or concretely showcases GEM impact or use of GEM products in your organization, email us at communication@globalquakemodel.org. We would love to feature your success stories! No images found. GALLERY 1/3 Gallery VIDEO RELATED CONTENTS

News GEM and Aon to Collaborate on the Development of a New Earthquake Model for Canada By: Mar 6, 2019 Share Facebook LinkedIn GEM and Aon’s Impact Forecasting catastrophe model development team have signed a partnership agreement to develop a new earthquake model for Canada based on global collaborative science and the latest publicly available data and information from Natural Resources Canada (NRCan). The new model is expected to be available towards the end of 2019. The partnership will help gain deeper understanding of earthquake risk in Canada. The new model will allow insurance underwriters to more accurate pricing of their insurance products as well as effectively manage their portfolios. Consumers will also benefit because the model is based on openly available data and assumptions that are fully transparent to everyone. The model will be implemented in Impact Forecasting’s risk modeling platform – ELEMENTS – as well as Oasis-based platforms. Impact Forecasting will support the use of the model in the Canadian market, which includes deployment, training and ongoing support. “GEM and Aon both value the importance of transparent and open hazard and risk modeling. We believe that this approach is key to better technical understanding of risk, and directly supports GEM’s initiative to promote the sharing of high quality open risk information globally,” said John Schneider, GEM Secretary General. “We have chosen to partner with GEM because of its global reputation for open and high-quality science and engineering-based risk modelling, combined with their close collaboration with Natural Resources Canada. In addition we are excited to bring enhanced understanding of this earthquake risk to the insurance industry with a goal of ultimately increasing resilience across Canada,” added Adam Podlaha, Head of Aon’s Impact Forecasting team. The model is being developed in phases starting with earthquake shaking including liquefaction, tsunami and other secondary perils. Tsunami modeling will be implemented in collaboration with University College London (UCL). The proposed modeling solution from Impact Forecasting will be based on GEM’s earthquake risk model for Canada, developed in collaboration with NRCan, which officially joined GEM as a public sponsor last year. NRCan leads a consortium of Canadian organizations including Public Safety Canada, Insurance Bureau of Canada, Defence Research and Development Canada, as well as academic and planning professionals. Phil Hill, Director, Geological Survey of Canada-Pacific (NRCan), and GEM Governing Board member for Canada, commented, “The GEM-IF Canada earthquake risk model is an important step in making credible and open disaster risk information available and accessible in Canada.” No images found. GALLERY 1/0 VIDEO RELATED CONTENTS

News Inception of DRR-pathways project in Vancouver, Canada By: Mar 21, 2019 Share Facebook LinkedIn On 15 February in Vancouver, Canada, GEM sponsor Natural Resources Canada held the project inception meeting for “DR Pathways: Incentives for mitigation & adaptation investments”. The three-year project, funded by the Canadian Safety and Security Program, aims to re-frame the risk assessment process around risk reduction strategies (planning scenarios) that will lead to proactive investment in mitigation and adaptation. Specific project objectives are to: Increase capabilities to model systemic risk and disaster recovery; Enable an evidence-based approach to disaster resilience planning; and Strengthen risk governance through knowledge exchange and community engagement. Present at the meeting were project participants from Natural Resources Canada (notably Phil Hill, GEM GB representative and Project Champion, and Murray Journeay, GEM Outstanding Award recipient), City of Vancouver, Emergency Management British Columbia, Fraser Basin Council, University of Victoria, and other local, regional and national organizations involved in risk assessment and resilience planning. The main purpose of the meeting was to introduce all of the project partners, establish the project governance structure, and to clarify the scope and timeline. Key outcomes of the meeting were: agreement on the guiding principles, adapted from GEM’s platform: open, collaborative, public good and credible; establishment of the Steering Committee (with Chair, Kathryn Forge, Emergency Management British Columbia); and results of brainstorming amongst participants regarding the selection of flood and earthquake impact scenarios for 1) post disaster response and recovery and 2) risk reduction and resilience planning. According to Murray Journeay, who led the development of the proposal, “This project will benefit from GEM’s global leadership in developing the methodology and tools for integrated risk assessment and using this approach to develop a more holistic and empowering view of systemic risk.” The meeting was an excellent forum for exchanging ideas among scientists/engineers, emergency managers and policy makers, on how to develop and integrate risk information to inform the emergency management and planning process through a systemic and holistic approach. GEM looks forward to working with all of the local, regional, provincial and national organizations to make this project an outstanding success. No images found. GALLERY 1/4 VIDEO RELATED CONTENTS

Publications ISC-GEM Global instrumental earthquake catalogue (1900-2009) Share Facebook LinkedIn Download 2012 | Report Here we describe the work of collecting, reviewing, digitizing and interpreting data from a multitude of historical sources: paper-based global earthquake catalogues as well as the individual observatory and network bulletins containing parameters of large earthquakes of the past. The preliminary earthquake selection was done using available magnitude estimates from different sources.

News Mapping Seismic Design in South America: New Study Highlights Gaps and Progress By: Oct 6, 2025 Sep 24, 2025 Share Facebook LinkedIn How many buildings in South America were constructed under seismic codes? A recent analysis led by Daniela González, GEM Exposure Analyst, and Vitor Silva, Head of Risk Engineering at GEM Foundation, provides an answer. The study examines the state of seismic design regulations across seven South American countries, providing crucial insights for earthquake risk reduction efforts. Tracking Building Codes and Seismic Safety The paper, Model of Seismic Design Regulations and Lateral Force Coefficients for Buildings in South America, published in Bulletin of Earthquake Engineering, investigates the evolution of seismic design standards in Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, and Venezuela. Using a methodology previously applied in Europe, the study offers a comparative analysis of how building codes have developed, the regions in which they were applied over time, and the extent to which they are applied in practice. A simplified method was introduced to estimate the proportion of buildings constructed under four seismic code levels – no code, low code, moderate code, and high code. The approach also determines lateral force coefficients for a typical mid-rise reinforced concrete structure under each category, providing a way to connect regulation levels with structural performance. Key Findings The study found that about 20% of the total building stock in the region, and 55% of reinforced concrete buildings, were constructed under regulations that include some form of seismic provisions. This indicates progress but also highlights the large share of buildings that remain outside modern standards. These results are particularly significant for improving seismic risk assessment models. By linking building practices to code levels, researchers and decision-makers can better estimate potential vulnerabilities in the built environment. The study also supports the ongoing work of the Global Earthquake Model (GEM) Foundation to improve access to information on seismic regulations and hazard design demand maps worldwide, with expansion of the study to other regions of the world expected over the next 12 months. Progress to Date GEM’s Global Seismic Regulation Database includes dedicated country pages that detail the current regulatory landscape in South America. For example, Chile is classified under high code, reflecting its long history of strong seismic standards, while countries such as Bolivia and Venezuela still have large portions of building stock without modern provisions. Summaries for Argentina, Colombia, Ecuador, and Peru also provide a clearer picture of the differences in adoption and enforcement across the region. View GEM’s country pages here. https://www.globalquakemodel.org/national-seismic-regulations Implications for Risk Reduction According to Daniela, the work has implications that go beyond the region: “By clarifying how many buildings were actually designed with seismic safety in mind, we can improve the accuracy of risk models and better inform preparedness strategies. This type of evidence helps bridge the gap between engineering practice and disaster risk reduction.” The study’s methodology is designed to evolve as new data and local expertise become available. Its adaptable framework allows integration of technological advancements and updated exposure information, making it a valuable tool not only for South America but for global initiatives to strengthen earthquake resilience. Link to the study: https://link.springer.com/article/10.1007/s10518-025-02287-7 No images found. GALLERY dgonzales study.jpeg dgonzales study.jpeg 1/1 VIDEO RELATED CONTENTS

License Request Form You have chosen to get more information about: Global Liquefaction Hazard Hazard Please check the link below to see if this product already meets your your requirements before submitting your request for a license. Thank you. DOWNLOAD THE OPEN VERSION Summary of steps to obtain a license for the requested product. Fill in the application form below. Click Submit. Please check your email Inbox or Spam folder for the summary of your request. You will then be contacted by the GEM Product Manager with either a request for more information, or a request to sign the license. If you do not hear from us within 2 weeks, please send an email to product@globalquakemodel.org . REQUEST DETAILS A. Requesting party information First Name Last Name Role/Job Email Business type Business type Other business Sector Sector Other sector B. License agreement signatory information The signatory must be someone who is authorised to sign license agreements on your behalf such as your immediate supervisor, manager or legal officer. If you’re a PhD student, the signatory must be your adviser or a university officer in charge of license agreements or similar legal documents. Full Name of Signatory Position Company Email of Signatory Organisation name Complete Address C. Purpose of request GEM is able to offer products for free because of the support of our project partners, national collaborators and institutional sponsors. All of GEM’s products are freely available for public good, non-commercial use, but with different license restrictions. In most cases we release products under an open license (e.g., CC BY-SA or CC BY-NC-SA), which permits (re)distribution. In this case, we are granting access under a more restricted license that forbids distribution or disclosure and requires signing by GEM and the licensee in order to better assure accountability for the confidentiality of the information. In order for GEM to properly assess your request, please answer the following questions below. 1. Explain briefly how will the GEM product be used e.g. project, research including the expected results and the foreseen public benefit. Minimum 60 words. 2. Will you be able to share the results of your work with GEM? YES NO 3. Will you be able to provide feedback to GEM on the quality and usefulness of this product via a survey? YES NO D. Privacy Policy By submitting this form, you consent to the processing of your personal data in accordance with our Privacy Policy and the EU General Data Protection Regulation (GDPR). We are committed to safeguarding your information and ensuring it is only used for the purpose outlined in this form. You have the right to access, rectify, or delete your data at any time. For more information, please refer to our Privacy Policy. I agree Words: 0 Email us at product@globalquakemodel.org if you're experiencing problems submitting your application. Thank you. Submit Thanks for submitting! You will be contacted as soon as possible Incomplete data. Please fill in all required fields. Thank you.