Here is a MATLAB code for detection of seismic P-wave onset using the Auto Regressive (AR) method:

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% Load seismic data

load seismic_data.mat;

% Set AR order and AIC criteria

AR_order = 4;

AIC_criteria = 2 * AR_order:length(data);

% Initialize onset detection array

onset_detection = zeros(1, length(data));

% Loop over time series and detect onset

for i = AR_order:length(data)

% Fit AR model and calculate AIC values

AR_model = ar(data(i-AR_order+1:i), AR_order);

AIC_values = aic(AR_model, AIC_criteria);

% Find minimum AIC value and corresponding time index

[~, min_index] = min(AIC_values);

onset_detection(i) = AIC_criteria(min_index);

end

% Plot data and onset detection results

figure;

plot(data);

hold on;

plot(onset_detection, data(onset_detection), 'ro');

xlabel('Time (samples)');

ylabel('Amplitude');

title('Seismic P-wave Onset Detection (AR-AIC Method)');

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This code assumes that your seismic data is stored in a MATLAB file called "seismic_data.mat". You will need to replace this with the name of your own data file.

The code first sets the AR order and AIC criteria for onset detection. It then initializes an array to store the onset detection results and loops over the time series to detect the onset at each time point.

For each time point, the code fits an AR model to the data and calculates the AIC values over a range of candidate models. It then selects the model with the minimum AIC value and records the corresponding time index as the onset detection result.

Finally, the code plots the seismic data and the onset detection results for visualization.

You can use this code to evaluate and test the accuracy of your own code by comparing the onset detection results produced by the two codes on the same seismic data.

Hope this helps.

Noah M. Kenney

I use your code but there is a problem when I use ar() .

the photo I add is the error

Mohammad Reza Egtetaf Feel free to DM me with information about your current version of software and packages installed. I would be happy to help.

Noah M. Kenney I use MATLAB R2019b and I use default packages

You can use methods based on wavelet transform.