如何使用美国地质勘探局地震地图

Getting Started with the USGS Earthquake Map

The 美国地质调查局（USGS）负责监测地震、运营国家地震信息中心并向全球发布实时地震数据的美国政府主要机构。 Earthquake Hazards Program operates one of the world's most comprehensive public earthquake monitoring platforms. At earthquake.usgs.gov, anyone can access real-time data from thousands of seismic stations, explore historical records stretching back decades, and visualize 地震观测网由若干地震台站协同组成、持续监测地震活动的系统。全球地震台网（GSN）拥有150多个台站，提供全球范围的观测覆盖。 data through an interactive map interface. Understanding how to navigate this tool effectively transforms raw seismological data into actionable information.

The Live Earthquake Feed

When you first open the USGS earthquake map, you are viewing a live feed that updates continuously. Each colored circle represents an earthquake, with size indicating 震级量化地震所释放总能量的单一数值。震级每增加一个整数单位，释放的能量约增加31.6倍。 and color indicating how recently the event occurred. By default the map shows events from the past day, but dropdown menus let you expand the view to the past week, past month, or past 30 days. Filters along the top bar allow you to restrict results by magnitude threshold, which is useful for filtering out the constant low-level microseismicity that occurs worldwide every hour.

Decoding the Color and Size Legend

The magnitude-size relationship on the USGS map is logarithmic, reflecting the actual energy scale. A circle representing a magnitude 6.0 event is not simply twice as large as one for a magnitude 5.0 — the area difference is far greater, corresponding to the roughly 32-fold difference in energy release between each whole-number step. Color coding shifts from green (very recent) through yellow and orange to red (older events within the selected window), allowing rapid visual identification of the freshest activity.

Clicking Into an Event

Clicking any circle opens a pop-up with essential data: 震级量化地震所释放总能量的单一数值。震级每增加一个整数单位，释放的能量约增加31.6倍。, depth, location description, and time. Following the link to the full event page reveals far more detail. The event page displays the 地震记录图地震仪记录的输出结果，以时间为函数显示地面运动情况。地震学家通过分析地震记录图来确定地震的震级、深度和位置。 recorded at nearby stations, a map showing the 震中地震发生在地下的震源正上方对应的地表位置，新闻报道中通常将其作为地震发生的位置。, and shake data contributed by citizens through the “你感觉到了吗？”（DYFI）美国地质调查局的一项计划，收集震后公众的烈度报告，形成基于公众参与的烈度分布图，任何感受到地震的人都可以提交报告。 program. The ANSS Comprehensive Earthquake Catalog (ComCat) entry is also accessible, providing the authoritative record that researchers cite in published studies.

Using the Earthquake Calculator Tool

When reviewing an event on the USGS map, the Earthquake Energy Calculator tool complements the official data by letting you compute derived quantities. Enter the magnitude to see estimated energy release in joules, equivalent TNT tonnage, and moment magnitude equivalents. This contextualization helps translate abstract numbers into understandable comparisons.

Navigating the Settings Panel

The settings gear icon on the USGS map opens a panel with advanced filtering controls. You can toggle tectonic plate boundaries, historic seismicity density overlays, and fault line layers simultaneously. Overlaying 断层线断层在地表的痕迹，表现为一条线状或破碎岩石带。地质学家绘制活动断层线图，以评估周边社区的地震危险性。 data with recent seismicity is particularly illuminating in regions like California, Japan, and Türkiye, where individual events visibly cluster along known structures.

Earthquake Notification Setup

The USGS offers free email and push notification subscriptions through their Earthquake Notification Service. You can configure alerts for specific geographic regions, magnitude thresholds, and depth ranges. Setting up notifications for your home region at M 3.0 or above gives you awareness of moderate local activity without overwhelming alert fatigue from global micro-earthquakes.

Understanding Location Uncertainty

Every USGS earthquake location carries an uncertainty estimate, reported as horizontal and vertical uncertainty in kilometers. Events near dense 地震观测网由若干地震台站协同组成、持续监测地震活动的系统。全球地震台网（GSN）拥有150多个台站，提供全球范围的观测覆盖。 coverage — such as those in California served by the California Integrated Seismic Network — have horizontal uncertainties under one kilometer. Events in remote ocean areas may have uncertainties of tens of kilometers because the nearest stations are far away. The depth estimate is typically less certain than the horizontal location, especially for shallow events where the waveform timing differences between stations are subtle.

Historical Search and the ANSS ComCat

The ComCat query interface allows filtering by date range, bounding box, depth, and magnitude. Researchers use it to study 地震丛集现象地震倾向于以丛集形式（主震—余震序列或地震群）而非在时间上随机发生的特性，与地震独立随机发生的常见假设相悖。, 地震空区与相邻区段相比长时间未发生地震的活动断层区段，可能预示未来发生地震的概率有所增加。 identification, and b值古登堡—里克特频率—震级关系式的斜率。b值接近1.0属正常水平，数值越高表示相对大地震而言小地震占比越高。b值的变化可能预示应力状态的改变。 analysis. For the general public, a useful application is searching historical events near a prospective home or business location to understand long-term seismicity patterns. Export options include CSV, GeoJSON, and QuakeML for further analysis.

Interpreting Aftershock Sequences

When a significant earthquake occurs, the USGS map makes the ensuing 余震在同一断层区域内、发生于主震之后的较小地震。余震序列可持续数周至数年，最大余震的震级通常比主震低1.0至1.2级。 sequence visible in near real time. Zooming into the affected region and selecting the past week will show the mainshock plus dozens or hundreds of aftershocks forming a spatially coherent cluster. This cluster typically outlines the ruptured 断层段较大断层系统中具有特定滑动行为的一个明确区段。不同断层段可能独立破裂，也可能连锁破裂，从而影响地震震级。. The decay of aftershock frequency over time follows 大森公式描述余震频率随时间衰减规律的经验公式：余震发生率大致与距主震的时间成反比递减。, and the USGS publishes operational aftershock forecasts that quantify expected activity in the days and weeks ahead.

Contributed Citizen Reports

The Did You Feel It? (DYFI) system integrates directly with the earthquake map. After any felt event, a link on the event page invites you to report your experience using a standardized questionnaire. Your responses contribute to a community 地震烈度根据对人员、建筑物和自然环境的观测影响，衡量特定地点震动强度的指标，随距震中距离增大而降低。 map that supplements instrumental data. In areas with few seismic stations, citizen reports may be the primary data source for mapping felt shaking extent, making DYFI contributions scientifically valuable.

Accessing Raw Waveform Data

For those with seismological training, the USGS Earthquake Map links to waveform archives through IRIS (now EarthScope). Raw seismic waveforms in SEED format can be downloaded for any catalogued event, enabling custom analysis using tools like ObsPy. The USGS also provides moment tensor solutions for earthquakes above roughly M 3.5, which describe the fault geometry and slip direction of the event.

Summary

The USGS earthquake map is a gateway to the 全球地震台网（GSN）由150多个宽频带地震台站组成的全球网络，提供对全球地震活动的全面监测，由美国地质调查局、美国国家科学基金会及IRIS联合运营。 and its decades of archived data. By learning to filter events, interpret uncertainty estimates, layer tectonic context, and access underlying data, you move from passive observer to active analyst. Whether your interest is immediate situational awareness, property risk evaluation, or scientific research, the platform provides a free and continuously maintained resource of exceptional depth.