Dataset for "Thermal Stressing of Volcanic Rock: Microcracking and Crack Closure Monitored through Acoustic Emission, Ultrasonic Velocity, and Thermal Expansion."

This README describes the contents of the dataset, split into P-wave velocity data (travel times, velocities, and raw signal waveforms), thermal expansion measurements, and acoustic emission monitoring data.Wave velocity dataCalculated velocitiesIn the folder /Acoustic velocity.For each experiment and heating/cooling cycle, the wave velocities are given in excel spreadsheets (e.g. EB_p_wave_data_cycle_1.xlsx). The columns contain the following data:* time: the time at which the measurement was made* TEMP: the furnace temperature* vp_cross_correlation: The P-wave velocity calculated using the cross-correlation method.Raw waveform dataThe raw waveform data is also provided for each heating/cooling cycle (e.g. EB_waveforms_cycle_1.csv). The CSV contains the text version of an array with shape (4001, N), where N is the number of measurements during a heating/cooling cycle. The first row of the file contains the times at which the measurement was made. The remaining 4000 rows of a column are the measured voltage values recorded at a 2 MHz sampling frequency.Thermal expansion dataIn the folder /Thermal expansionFor each of the three samples, there is an excel spreadsheet containing the following columns (e.g., Elongation_EB.xlsx).The sample elongation is measured over three heating and cooling cycles and the columns contain the following data:* Temp [°C]: sample temperature in degrees Celsius* Time/min: time elapsed in minutes* dL/Lo: change in length relative to initial lengthAcoustic emission (AE) monitoring dataIn the folder /Acoustic emissionsFor each experiment and heating/cooling cycle, the time and characteristics of each AE hit are given in excel spreadsheets (e.g. EB_AE_cycle_1.xlsx). The columns contain the following data:TIME: The time of the AE hit from the start of the experiment in seconds.RISE: The rise time from an AE signal’s first threshold crossing to its peak.COUN: The number of counts, or number of times the AE signal crosses the AE threshold.ENER: A measure of energy released during the AE event, equal to the integral of the voltagesignal over the duration of the AE hitDURATION: AE Duration is defined as the time from the first threshold crossing to the end of the last.AMP: The AE Amplitude is the maximum voltage (negative or posotive) during an AE hit (in dB).A-FRQ: The average frequency, equal to COUN / DURATION.RMS: The root mean square of the recorded voltage signal.ABS-ENERGY: The absolute energy of the AE signal, calculated as integral of the squared voltage waveform divided by the reference resistance (10 kohm).TEMP: The temperature at the time of the AE hitCUMABS-ENERGY: The cumulative absolute energy.CUMHITS: The cumulative number of AE hits本说明文档用于介绍本数据集的构成，数据集涵盖P波速度数据（包含走时、速度及原始信号波形）、热膨胀测量数据与声发射（Acoustic emission, AE）监测数据三大类。 ### 波速数据 #### 计算波速数据 相关文件存储于/Acoustic velocity文件夹中。针对每次实验及每个升降温循环，波速数据均以Excel电子表格形式存储（示例文件：EB_p_wave_data_cycle_1.xlsx）。表格列包含以下数据： * time：测量时刻 * TEMP：炉内温度 * vp_cross_correlation：采用互相关方法计算得到的P波速度。 #### 原始波形数据 每个升降温循环均配套提供原始波形数据（示例文件：EB_waveforms_cycle_1.csv）。该CSV文件存储形状为(4001, N)的数组的文本格式，其中N为单次升降温循环期间的总测量次数。文件首行记录各测量时刻，其余4000行对应2 MHz采样频率下采集的实测电压值。 ### 热膨胀数据 相关文件存储于/Thermal expansion文件夹中。针对三个试样分别设有对应的Excel电子表格（示例文件：Elongation_EB.xlsx），表格列包含以下数据： * Temp [°C]：试样温度，单位为摄氏度 * Time/min：已流逝时长，单位为分钟 * dL/Lo：相对于初始长度的相对长度变化量。 ### 声发射监测数据 相关文件存储于/Acoustic emissions文件夹中。针对每次实验及每个升降温循环，声发射事件的时刻与特征参数均存储于Excel电子表格中（示例文件：EB_AE_cycle_1.xlsx）。表格列包含以下数据： * TIME：声发射事件距实验起始时刻的时长，单位为秒 * RISE：声发射信号从首次越过阈值至达到峰值的上升时间 * COUN：计数次数，即声发射信号越过声发射阈值的总次数 * ENER：声发射事件释放能量的量度，等于声发射事件持续期间电压信号的积分值 * DURATION：声发射时长，定义为从首次越过阈值至最后一次信号衰减结束的总时长 * AMP：声发射幅值，为声发射事件期间的最大电压（正或负），单位为dB * A-FRQ：平均频率，等于COUN与DURATION的比值 * RMS：记录的电压信号的均方根值 * ABS-ENERGY：声发射信号的绝对能量，通过将电压波形平方后的积分值除以参考电阻（10 kΩ）计算得到 * TEMP：声发射事件发生时刻的试样温度 * CUMABS-ENERGY：累积绝对能量 * CUMHITS：累积声发射事件总次数