The modern news cycle has been fundamentally reshaped by the rapid exchange of information online. As a result, media framing shifts dynamically as new information, political responses, and social reactions emerge. Understanding how these narratives form, propagate, and evolve is essential for interpreting public discourse during moments of crisis. In this study, we examine the temporal and semantic dynamics of reporting for violent and catastrophic events using a large-scale corpus of 126,602 news articles collected from online publishers. We quantify narrative change through publication volume, semantic drift, semantic dispersion, and term relevance. Our results show that sudden events of impact exhibit structured and predictable news-cycle patterns characterized by rapid surges in coverage, early semantic drift, and gradual declines toward the baseline. In addition, our results indicate the terms that are driving the temporal patterns.

翻译：现代新闻周期已因在线信息的快速交换而从根本上发生了重塑。因此，随着新信息、政治回应和社会反应的涌现，媒体框架动态变化。理解这些叙事如何形成、传播和演变，对于解读危机时期的公众话语至关重要。本研究利用从在线媒体收集的126,602篇新闻文章构成的大规模语料库，考察了暴力和灾难事件报道的时间与语义动态。通过发文量、语义漂移、语义离散度以及术语相关性，我们量化了叙事变化。结果表明，突发冲击事件呈现出结构化且可预测的新闻周期模式，其特点为报道量迅速激增、早期语义漂移，以及逐渐回归基线水平。此外，我们的结果揭示了驱动这些时间模式的关键术语。