Earthquake early warning systems are very important in mitigating more severe damage from earthquake events. Therefore, the analysis of earthquake signals is essential to obtain precise and accurate timing from earthquake stations in Indonesia. In this work, we have systematically investigated the time arrival of the P-wave from the earthquake signal accelerometer in the West Java region, which measured from 2009 to 2023 with magnitudes varied from M 4.0- to M 7.3. We have carefully filtered the raw data by using a Butterworth highpass filter with a cut-off frequency of 0.075 Hz to produce good data before analyzing the time of arrival of the signal. Then, the Initial Power of the P-wave (IPP) method was applied to the filtered signal data with various longtime and short-time window widths, including various SNRs. Interestingly, the results showed the average deviation of IPP was around 0.053 seconds compared with the conventional method, such as Short Time/Long Time Average (STA/LTA) was around 0.328 seconds. This means the IPP method was better accuracy than the conventional method and its potential for analysing signal in earthquake early warning system. © 2025 Institute of Physics Publishing. All rights reserved.