[Paper Review] An example of regional seismicity recovery on June 22, 2020, using waveform cross-correlation

Ivan Kitov|arXiv (Cornell University)|Feb 17, 2026

High-pressure geophysics and materials0 citations

TL;DR

The paper demonstrates using waveform cross-correlation to recover regional seismicity on June 22, 2020 and revisits events potentially missed or below detection thresholds by IDC in the context of nuclear test monitoring.

ABSTRACT

June 22nd, 2020 was an important day for nuclear test monitoring. The US undersecretary, Thomas DiNanno, made an official claim that a secret nuclear test was conducted at the Lop Nor testing site on that day. However, the Provisional Technical Secretariat (PTS) of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) reported that there were no seismic events consistent with a nuclear explosion on that date. This means that the event was either hidden under the threshold of the international monitoring system (IMS), or it was missed by the international data center (IDC). Alternatively, no event occurred. All scenarios are of interest to the scientific community. The routine processing of seismic data by the IDC is well documented in open sources. The threshold for detection is not uniform across the globe, especially in continental areas. Additionally, it is not low enough to detect weapon-sized explosions using the cavity decoupling method. There are methods to lower this threshold using waveform cross-correlation (WCC) techniques. On June 22th, 2020, the IDC ran a preliminary pipeline for processing seismic data from the IMS. This was done in a testing mode. Since 2020, the development of WCC methods has allowed for revisiting cases and obtaining high-quality reports on events that were not reported five years ago.

Motivation & Objective

• Assess whether a seismic event on June 22, 2020 could be detected or missed by the IDC thresholds.
• Show how waveform cross-correlation (WCC) can lower regional detection thresholds for seismic monitoring.
• Revisit cases not reported by IDC to evaluate the potential of WCC methods since 2020.
• Discuss implications of WCC-based recovery for IMS data processing and event reporting.

Proposed method

• Describe the IDC preliminary processing pipeline run in testing mode for 2020 data.
• Apply waveform cross-correlation (WCC) techniques to explore recovery of regional seismicity.
• Argue that WCC methods developed since 2020 enable high-quality reports on previously unreported events.
• Contextualize findings within nuclear test monitoring and detection threshold challenges.

Experimental results

Research questions

• RQ1 Can waveform cross-correlation reveal seismic events on 22 June 2020 that were not reported by IDC or were below its threshold?
• RQ2 To what extent can WCC lower regional detection thresholds in continental areas relevant to IMS monitoring?
• RQ3 How has the development of WCC since 2020 changed the ability to revisit and confirm potential events in historical monitoring data?

Key findings

• WCC methods developed since 2020 allow revisiting cases and obtaining high-quality reports on events not reported five years ago.
• There is potential for WCC to lower detection thresholds regionally, improving sensitivity in continental areas.
• The IDC pipeline run in testing mode in 2020 highlights ongoing opportunities to reassess past events with improved techniques.